05 Appendix 2a
Appendix 2
Transportation Impact Analysis
CITY OF FEDERAL WAY
CITY CENTER PLANNED ACTION EIS
Federal Way City Center Transportation Impact Analysis
6/20/2006 i Mirai Transportation
Planning & Engineering
Table of Contents
INTRODUCTION.........................................................................................................................1
Outline of Study........................................................................................................................1
Project Description...................................................................................................................1
Site Location..............................................................................................................................2
Existing Land Use.....................................................................................................................4
Proposed Land Use...................................................................................................................4
Approved Projects in the Vicinity...........................................................................................6
SCOPE OF IMPACT ANALYSIS..............................................................................................6
Study Intersections...................................................................................................................6
Definition of Impact..................................................................................................................7
INVENTORY OF EXISTING AND PLANNED TRANSPORTATION SYSTEM...............8
Roadway Facilities....................................................................................................................8
Functional Classification........................................................................................................9
System Description.................................................................................................................9
Right-of-Way........................................................................................................................11
Base Year (2004) Volumes...................................................................................................12
Base Year (2004) Volumes...................................................................................................13
Existing Traffic Operations...................................................................................................20
Parking..................................................................................................................................21
Collision Data.......................................................................................................................22
Future Conditions Analysis...................................................................................................24
Transit Services.......................................................................................................................28
Pedestrian Facilities................................................................................................................30
Pedestrian Facilities................................................................................................................31
Bicycle Facilities......................................................................................................................31
IMPACTS OF ALTERNATIVES - 2009..................................................................................35
Trip Generation.....................................................................................................................35
Modal Split............................................................................................................................36
No Action (Alternative 3).......................................................................................................36
Traffic Growth......................................................................................................................36
Traffic Volumes....................................................................................................................37
2009 No Action Traffic Operations......................................................................................44
2009 No Action Deficiencies................................................................................................45
Parking Requirement............................................................................................................45
Traffic Safety Impact............................................................................................................46
Transit Service Impact..........................................................................................................46
Pedestrian Accessibility........................................................................................................46
Bicycle Mobility Impact.......................................................................................................46
Proposed Mitigation..............................................................................................................46
Alternative 1............................................................................................................................48
Trip Generation, Distribution, and Assignment....................................................................48
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Traffic Volumes....................................................................................................................48
2009 Alternative 1 Traffic Operations..................................................................................48
2009 Alternative 1 Deficiencies............................................................................................58
Parking Requirements...........................................................................................................59
Traffic Safety Impact............................................................................................................60
Transit Service Impact..........................................................................................................60
Pedestrian Accessibility........................................................................................................60
Bicycle Mobility Impact.......................................................................................................60
Proposed Mitigation..............................................................................................................60
Alternative 2............................................................................................................................62
Trip Generation, Distribution, and Assignment....................................................................62
Traffic Volumes....................................................................................................................62
2009 Alternative 2 Traffic Operations..................................................................................62
2009 Alternative 2 Deficiencies............................................................................................72
Parking Requirement............................................................................................................73
Traffic Safety Impact............................................................................................................73
Transit Service Impact..........................................................................................................74
Pedestrian Accessibility........................................................................................................74
Bicycle Mobility Impact.......................................................................................................74
Proposed Mitigation..............................................................................................................74
2014 FORECASTS.....................................................................................................................76
Forecast Methodology............................................................................................................76
Roadway Improvement Assumptions...................................................................................76
Trip Generation......................................................................................................................76
Trip Distribution and Assignment........................................................................................77
2014 No Action Traffic Volumes...........................................................................................77
2014 Alternative 1 Traffic Volumes......................................................................................81
PM Peak Hour.......................................................................................................................81
AM Peak Hour......................................................................................................................81
Saturday Peak Hour..............................................................................................................81
2014 Alternative 2 Traffic Volumes......................................................................................85
PM Peak Hour.......................................................................................................................85
AM Peak Hour......................................................................................................................85
Saturday Peak Hour..............................................................................................................85
MITIGATION.............................................................................................................................89
Mitigation Cost Assumptions.................................................................................................89
Mitigation Improvements.......................................................................................................90
Comparison of Alternatives...................................................................................................90
Timing of Implementation.....................................................................................................93
Additional Mitigation.............................................................................................................94
ALTERNATIVE MODE SUPPORT MEASURES .........................................................97
EMPLOYER-BASED TDM MEASURES .......................................................................97
OTHER STRATEGIES ......................................................................................................98
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Tables
Table 1. FWCC Land Uses – January 2002....................................................................................4
Table 2. Proposed Development 2004-2009...................................................................................5
Table 3. Proposed Development 2010-2014...................................................................................5
Table 4. Study Intersections............................................................................................................7
Table 5. Level of Service Definitions.............................................................................................8
Table 6. Characteristics of Functional Classifications of Streets...................................................9
Table 7. Right-of-Way for Major Area Streets.............................................................................11
Table 8. 2004 Intersection Operations PM Peak, AM Peak, and Saturday Peak........................20
Table 9. Existing Parking Supply by Block..................................................................................21
Table 10. Existing Parking Requirements....................................................................................22
Table 11. 2000-2002 Intersection Collision Rates........................................................................23
Table 12. 2000-2002 Corridor Collision Rates.............................................................................24
Table 13. Assumed Annual Traffic Growth Rates 2004-2009.....................................................24
Table 14. 2005-2010 Transportation Improvement Program.......................................................26
Table 15: ITE Trip Generation Rates for Federal Way City Center.............................................35
Table 16: Summary of Peak Hour Trip Generation for Federal Way City Center (2004-2009)..36
Table 17. 2009 Traffic Operations No Action (Alternative 3).....................................................44
Table 18. Additional Parking Required for Alternative 3 at Buildout..........................................45
Table 19. No Action Proposed Mitigation....................................................................................47
Table 20. 2009 Alternative 1 Intersection Operations.................................................................58
Table 21. Additional Parking Required for Alternative 1 at Buildout..........................................59
Table 22. Alternative 1 Mitigation................................................................................................61
Table 23. 2009 Alternative 2 Intersection Operations.................................................................72
Table 24. Additional Parking Required for Alternative 2 at Buildout..........................................73
Table 25. Alternative 2 Mitigation................................................................................................75
Table 26: Summary of Trip Generation for Federal Way City Center (2010-2014)....................77
Table 27. Mitigation Cost Assumptions......................................................................................89
Table 28. PM Peak Hour 2009 Mitigation....................................................................................91
Table 29. AM Peak Hour 2009 Mitigation...................................................................................92
Table 30. Saturday Peak Hour 2009 Mitigation...........................................................................93
Table 31. Intersection Operations by Peak Hour with Mitigation................................................94
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Figures
Figure 1. Location Map................................................................................................................3
Figure 2. Functional Classification............................................................................................10
Figure 3. Proposed FWCC Street Network................................................................................12
Figure 4. Existing PM Volumes...........................................................................................14-15
Figure 5. Existing AM Volumes..........................................................................................16-17
Figure 6. Existing Saturday Volumes..................................................................................18-19
Figure 7. 2005-2010 TIP............................................................................................................27
Figure 8. Existing Transit Services............................................................................................29
Figure 9. Existing Park and Ride Lots.......................................................................................30
Figure 10. Existing Pedestrian Facilities....................................................................................32
Figure 11. Existing Bicycle Facilities........................................................................................33
Figure 12. Future Pedestrian and Bicycle Facilities...................................................................34
Figure 13. 2009 No Action PM Peak Turning Volumes......................................................38-39
Figure 14. 2009 No Action AM Peak Turning Volumes.....................................................40-41
Figure 15. 2009 No Action Saturday Peak Turning Volumes.............................................42-43
Figure 16. 2009 Alternative 1 PM Peak Trip Distribution.........................................................49
Figure 17. 2009 Alternative 1 AM Peak Trip Distribution........................................................50
Figure 18. 2009 Alternative 1 Saturday Peak Trip Distribution................................................51
Figure 19. 2009 Alternative 1 PM Peak Turning Volumes..................................................52-53
Figure 20. 2009 Alternative 1 AM Peak Turning Volumes.................................................54-55
Figure 21. 2009 Alternative 1 Saturday Peak Turning Volumes.........................................56-57
Figure 22. 2009 Alternative 2 PM Peak Trip Distribution Volumes.........................................63
Figure 23. 2009 Alternative 2 AM Peak Trip Distribution Volumes.........................................64
Figure 24. 2009 Alternative 2 Saturday Peak Trip Distribution................................................65
Figure 25. 2009 Alternative 2 PM Peak Turning Volumes..................................................66-67
Figure 26. 2009 Alternative 2 AM Peak Turning Volumes.................................................68-69
Figure 27. 2009 Alternative 2 Saturday Peak Turning Volumes.........................................70-71
Figure 28. 2014 Volumes – PM Peak Hour – No Action..........................................................78
Figure 29. 2014 Volumes – AM Peak Hour – No Action..........................................................79
Figure 30. 2014 Volumes – Saturday Peak Hour – No Action..................................................80
Figure 31. 2014 Volumes – PM Peak Hour – Alternative 1......................................................82
Figure 32. 2014 Volumes – AM Peak Hour – Alternative 1......................................................83
Figure 33. 2014 Volumes – Saturday Peak Hour – Alternative 1..............................................84
Figure 34. 2014 Volumes – PM Peak Hour – Alternative 2......................................................86
Figure 35. 2014 Volumes – AM Peak Hour – Alternative 2......................................................87
Figure 36. 2014 Volumes – Saturday Peak Hour – Alternative 2..............................................88
Federal Way City Center Transportation Impact Analysis
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Introduction
This study describes the transportation impacts associated with the development of the
Federal Way City Center (FWCC) project located in Federal Way, WA. This study
assesses the expected impact of the proposed land use changes in the City Center
planning area on the City’s transportation systems, including roadways and
intersections, transit, bicycles, and pedestrian facilities, and identifies actions and
improvements to mitigate the impacts. The study follows the Transportation Impact
Analysis (TIA) guidelines from the City of Federal Way Public Works Department dated
June 2004. Individual development projects proposed within the FWCC planning area
may be required to provide additional analysis of the specific impact of their project on
the transportation system as directed by the Director of Public Works.
Outline of Study
This study analyzes existing conditions (2004) and the short-term (2009) and longer-
term (2014) impacts of the three FWCC project alternatives. The existing traffic
operations (Base Year) and transportation systems are described for the AM peak, PM
peak, and Saturday peak hour periods. Future traffic operations are described for two
action (Alternatives 1 and 2) and one no-action (Alternative 3) alternative for 2009 and
2014 for the AM peak, PM peak, and Saturday peak hour periods. The year 2009 was
selected to correspond to the City’s 6-yearTransportation Improvement Program (TIP)1
and to Phase 1 of the Federal Way City Center’s development (see the City Center
Planned Action Environmental Impact Statement, Jones and Stokes, Incorporated,
2005, for further details). The year 2014 represents the completion of proposed
development based on the City of Federal Way’s City Center Market Analysis (Eco
Northwest 2002). The 2009 analysis provides a detailed description of the expected
transportation impacts and proposed mitigation of the proposed alternatives. The 2014
analysis provides a more generalized description of future transportation impacts
associated with the FWCC plan. A technical appendix to this document provides details
about the scope of work, assumptions, and analysis results for this study. Additional
technical information is available on compact disc from the City of Federal Way.
Project Description
The proposed FWCC will develop an urbanized central core within Federal Way
containing a mix of land uses including housing, retail, and civic uses. Chapter 7 (Page
vii-1) of the City of Federal Way Comprehensive Plan (2002) describes the principal
purposes of the FWCC as to:
Create an identifiable downtown that is the social and economic focus of the City;
Strengthen the City as a whole by providing for long-term growth in employment
and housing;
Promote housing opportunities close to employment;
1 Projects from the updated 2005-2010 TIP were applied to the 2009 model year.
Federal Way City Center Transportation Impact Analysis
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Support development of an extensive regional transportation system;
Reduce dependency on automobiles;
Consume less land with urban development;
Maximize the benefit of public investment in infrastructure and services;
Reduce costs of and time required for permitting;
Provide a central gathering place for the community; and
Improve the quality of urban design for all developments.
This vision will be carried out by encouraging a compact form of development that will
mix retail, commercial, and residential land uses. The FWCC transit center and the
FWCC Park & Ride will be a key component of the planning area, supported by a high
level of non-motorized facilities, amenities, and transit services that will reduce
dependency on the automobile and provide transportation choices. Further information
on the FWCC and its role in the City’s development plans are found in Chapter 7 of the
City of Federal Way Comprehensive Plan (2002) and the City Center Planned Action
EIS (Jones and Stokes, Incorporated, 2005).
Site Location
Figure 1 illustrates the FWCC planning area for this analysis. The planning area, the
subject of this analysis, is a subset of the area designated in the City Center Core and
Frame (2002 City of Federal Way Comprehensive Plan Chapter 7), which included
areas west and east of the planning area. The study area analyzed represents the area
surrounding the new FWCC transit center, the focal point of the area’s development.
The planning area is centered along both sides of S 320 Street and 20 Avenue S,
forming three distinct blocks areas that include the Hillside Plaza shopping area and
school district offices, SeaTac Plaza and SeaTac Village, and the Commons at Federal
Way (formerly the SeaTac Mall). The boundaries of the planning area are S 312 Street
(north), S 324 Street (south), Pacific Highway S/SR-99 (west) and 23 Avenue S (east).
The area is divided into three blocks to allow the detailed analysis of land uses and
future development.
Block 1 consists of the northern portion of the project area and is bounded on the
north by S 312 Street, on the west by Pacific Highway South, on the south by
South 316 Street and on the east by 23 Avenue S.
Block 2 is located in the central portion of the project area and is bounded on the
north by S 316 Street, on the west by Pacific Highway South, on the south by S
320 Street and on the east by 23 Avenue S.
Block 3 is located in the southern portion of the project area and consists mainly
of The Commons at Federal Way (formerly SeaTac Mall). Block 3 is bounded on
the north by S 320 Street, on the west by Pacific Highway South, on the south by
S 324 Street and on the east by 23 Avenue S.
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Source: Federal Way City Center Planned Action EIS, 2005
Figure 1. Location Map
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Existing Land Use
The existing land uses are primarily retail and service businesses. As the principal retail
center of Federal Way, the area includes many of the City’s main shopping areas
including: The Commons at Federal Way (SeaTac Mall), SeaTac Village, Center Plaza,
SeaTac Plaza, and Hillside Plaza. Principal retailers in the area include Sears, Bon-
Macy’s, Target, and Wal-Mart. Other activities in the area include hotels, office space,
and a variety restaurants and eateries.
Table 1 describes the make up of the FWCC. The existing land uses within the City
Center include a mix of office, retail, and other uses, with little residential development.
Much of the remaining area is devoted to surface parking.
Table 1. FWCC Land Uses – January 2002
Commercial
(retail, office, restaurant,
services)
Residential Hotel
Block 1 538,224 sf 190 units --
Block 2 500,221 sf N/A 230 rooms
Block 3 850,469 sf N/A --
Total 1,888,914 sf 190 units 230 rooms
Source: Federal Way City Center Planned Action EIS, Jones and Stokes, Inc. 2005. Referencing King
County, WA. Parcel Viewer, Accessed 12-18-2003.
Proposed Land Use
The FWCC is proposed as a mixed-use development that will provide the variety of land
uses needed to create an urban center within the City of Federal Way. Table 2
describes the assumed mix of land uses applied in this analysis for each of the three
block areas. The two action alternatives assume the same amount of intensified
development within the FWCC area, but differ in the location of growth throughout the
planning area. Alternative 1 would concentrate development near S 320 Street (Blocks
2 and 3), while Alternative 2 would distribute the growth throughout FWCC plan area.
The No Action alternative (Alternative 3) assumes only the future growth identified in the
Chapter 7 of the City of Federal Way Comprehensive Plan (2002).
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Table 2. Proposed Development 2004-2009
No Action Alternative 1 Alternative 2
Block
1
Block
2
Block
3
Block
1 Block 2 Block 3 Block 1 Block 2 Block 3
Retail (sf) 34,395 41,697 34,041 67,500 202,500 180,000 153,000 153,000 144,000
Office (sf) 20,554 17,128 6,859 37,500 112,500 60,000 81,000 81,000 48,000
Lodging
(rooms) 0 0 0 60 180 120 132 132 96
Residential
(units) 23 31 31 75 225 150 165 165 120
Civic (sf) 0 0 0 0 0 0 0 0 0
Other (sf) 3,664 3,022 1,210 0 0 0 0 0 0
Structured
Parking
(stalls)
0 0 0 0 150 300 175 0 240
Source: Federal Way City Center Planned Action EIS, Jones & Stokes, Incorporated, 2005.
Table 3 lists the amount of expected development for each alternative within the FWCC
between 2010 and 2014. Overall growth for the action alternatives (Alternative 1 and 2)
is identical with Alternative 1 concentrating the growth in Blocks 1 and 2 and Alternative
2 balancing the growth between the three blocks.
Table 3. Proposed Development 2010-2014
No Action Alternative 1 Alternative 2
Block 1 Block 2 Block 3 Block 1 Block 2 Block 3 Block 1 Block 2 Block 3
Retail (sf) 22,602 27,400 22,371 45,000 135,000 120,000 102,000 102,000 96,000
Office (sf) 23,962 19,982 8,002 25,000 75,000 40,000 54,000 54,000 32,000
Lodging
(rooms) 0 0 0 40 120 80 88 88 64
Residential
(units) 28 39 34 50 150 100 110 110 80
Civic (sf) 0 0 0 0 50,000 50,000 50,000 50,000 0
Other (sf) 4,275 3,526 1,412 0 0 0 0 0 0
Structured
Parking
(stalls)
0 0 0 0 100 200 0 175 160
Source: Federal Way City Center Planned Action EIS, Jones & Stokes, Incorporated, 2005.
Each of these land use alternatives were assigned to the City of Federal Way’s
Transportation Analysis Zone (TAZs) for the development of the traffic forecasting
model in EMME/2. The land use, zone structure map, and the assumptions used in the
traffic modeling are located in the Technical Appendix B.
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Approved Projects in the Vicinity
The TIA includes the expected impacts of approved projects in the vicinity of the FWCC
area as part of the baseline assumptions to the traffic model. Three projects were
identified for inclusion in the scope of work:
The Christian Faith Center, a recently approved development of a church and
school on S 336th Street between Highway 99 and Interstate 5, will include a
4,500-seat sanctuary/auditorium, with meeting spaces, a bookstore, and offices;
and a school building with recreation facilities and play fields.
The Federal Way Transit Center was assumed as part of the baseline model
assumptions along with the S 317 Street transit/HOV ramps that connect to I-5.
The final project, the “Triangle Study” was not complete at the time of this report.
The study is primarily designed to improve safety and efficiency of the area
where of Interstate-5, SR-18, SR 161 interact with S 348 Street in Federal Way.
Scope of Impact Analysis
The TIA describes the impacts of the existing and future transportation system. The
existing analysis describes area traffic volumes, traffic operations, traffic safety, and
transit service for the AM, PM and Saturday peak hours. The future conditions analysis
includes the cumulative impacts of traffic increases associated with the each alternative,
general traffic growth (background traffic) and traffic associated with other development
projects and improvements. The future year analysis also assumes the completion of
projects within the City of Federal Way’s 2005-2010 6-year TIP. Appendix A includes
the scope of work for the project.
Study Intersections
Under the City’s direction a two-tier process was used to identify the scope of the study
intersections for the FWCC analysis. The first tier of this analysis followed the procedure
described in the City of Federal Way’s Guidelines for the Preparation of Transportation
Impact Analyses (June 2004). The first tier includes existing and future transportation
facilities affected by 10 or more trips in both directions during the evening PM peak hour
and 100 or more trips during other the AM and Saturday peak hours. Appendix C
provides the results of this analysis. The second tier reviewed the results from the level
of service and the volume-to-capacity ratio analyses conducted for the intersections
identified in the first tier to identify the existing and future locations likely to exceed the
City’s minimum acceptable level of service standard (LOS E or better with a
volume/capacity ratio of less than 1.00 for signalized intersections). Additional
intersections were added by the consultant as a result of refinements to the traffic model
and at the direction of the City staff.
Table 4 lists the study intersections within the area. A total of 27 intersections analyzed
for existing (2004) and future (2009). The AM peak hour analyzed 10 intersections, the
PM peak hour analyzed 22 intersections, and the Saturday peak hour analyzed 14
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intersections. These intersections were analyzed for existing and future conditions to
describe the impact of the FWCC plan on the transportation system. Throughout this
document the results of the PM peak hour analysis are reported first, the AM peak hour
second, and Saturday peak hour last.
Table 4. Study Intersections
PM Peak AM Peak SAT Peak
S 272 St & Pacific Hwy S (City of Kent) X X X
S 272 St & I-5 SB southbound Ramp (WSDOT) X X X
S 272 St & I-5 NB northbound Ramp (WSDOT) X X X
S 272 St & Military Rd S (City of Kent) X X X
S 288th St & Pacific Hwy S X
S 288th St & Military Rd S X
S Dash Point Rd & Pacific Hwy S X
S 312 St & Pacific Hwy S X X
S 312 St & 28 Av S X
S 316 St & Pacific Hwy S X
SW 320 St & 21 Av SW X
S 320 St & 1 Av S X X X
S 320 St & Pacific Hwy S X X
S 320 St & 20 Av S X
S 320 St & 23 Av S X X
S 320 St & I-5 SB southbound Ramp (WSDOT) X X X
S 320 St & I-5 NB northbound Ramp (WSDOT) X
S 320 St & Military Rd S (Unincorporated King County) X
S 324 St & Pacific Hwy S X X
SW 336 St & 21 Av SW X
S 336 St & Pacific Hwy S X X
SW 340 St & Hoyt Rd SW X X X
SW Campus Dr & 1 Av S X
S 348 St & Pacific Hwy S X
SW 356 St & 21 Av SW X
S 356 St & Pacific Hwy S X
S 356 St & Enchanted Pkwy S X
Number of Intersections Analyzed 22 10 14
Definition of Impact
The City of Federal Way follows the Highway Capacity Manual (HCM) methodology to
calculate the impact of a project on area intersections. Level of Service (LOS) is a
measure of the quality of traffic operations at an intersection. LOS uses an A to F scale,
with LOS A representing minimal traffic delays and LOS F representing severe
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congestion and long delays. The LOS is measured using the average control delay of
the intersection and is reported for the overall intersection for signalized intersections
and all-way stops, and for the worst movement of unsignalized intersections. Table 5
describes the LOS for signalized and unsignalized intersections.
Table 5. Level of Service Definitions
LOS Signalized Delay per Vehicle
(sec/veh)
Unsignalized Delay per Vehicle
(sec/veh)
A 0-10 0-10
B >10-20 >10-15
C >20-35 >15-25
D >35-55 >25-35
E >55-80 >35-50
F >80 >50
Source: Highway Capacity Manual (HCM 2000, Transportation Research Board)
The HCM methodology also calculates volume to capacity ratio to express the extent an
intersection is below or above its theoretic capacity. The HCM methodology uses the
volume to capacity of the critical movements of the intersection to provide an overall v/c
measure (Xc).
The City of Federal Way’s Guidelines for the Preparation of Transportation Impact
Analyses establishes analysis thresholds to define an impact requiring mitigation. The
City uses a combined threshold that defines an impact as: (1) intersections operating at
worse than LOS E for signalized and all-way stop controlled intersections and/or (2) an
overall volume/capacity ratio (Xc) of equal to or greater than 1.0, as calculated by the
Highway Capacity Manual methodology. For unsignalized intersections other than all-
way stops, an impact occurs when the lane volume/capacity ratio for any lane group
must is equal to or greater than the 1.0 standard.
Inventory of Existing and Planned Transportation System
This section describes the existing and planned major transportation systems within the
planning area, including the roadway system, traffic volumes, intersection operations,
collision data, transit services, and bicycle and pedestrian facilities.
Roadway Facilities
The main component of the transportation system is the roadway system. This section
describes the base year (2004) roadway system including the functional classification,
system description, right-of-way, traffic volumes, intersection operations (level of
service), and collision history.
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Functional Classification
Figure 2 shows the functional classification of the Federal Way arterial system within the
planning area. Table 6 describes the general definition of the functional classification
found in Chapter 3 of the City of Federal Way Comprehensive Plan (2003 revision).
Table 6. Characteristics of Functional Classifications of Streets
Source: Federal Way City Center Comprehensive Plan 2003 revision (Chapter 3), page III-30.
System Description
The City of Federal Way roadway system serves both local and regional roles providing
access to residents and businesses as well as connections to adjacent and regional
destinations. Primary roadways and intersections within the planning area are described
below:
Interstate 5 is the primary north-south interstate freeway in western Washington.
I-5 has five travel lanes north of S 320 Street and four lanes south of S 320
Street, with a posted speed limit of 60 mph. Study intersections connecting with
the I-5 ramps include the northbound and southbound ramps at S 320 Street, the
S 317 Street direct access ramps and at S 272 Street.
Pacific Highway S. (SR-99) is a five to seven lane principal arterial connecting
Federal Way with the City of Tacoma to the south and the City of Kent to the
north. The posted speed limit is 40 mph. Study intersections along SR-99
include S 272 Street, S Dash Point Rd, S 312 Street, S 316 Street, S 320 Street,
S 324 Street, S 336 Street, S 348 Street, and S 356 Street.
Right-of-way Width7
Road Classification Number of
Lanes Existing Code Posted Speed
Expected Daily
Traffic
Interstate/Freeways 4+ (varies) Varies 60 mph 30,000+
Principal Arterial 2 to 7 68' to 124' 35-50 mph 5,000+
Minor Arterial 2 to 5 68' to 106' 30-40 mph 5,000-35,000
Principal Collector 2 to 5 68' to 100' 25-35 mph 5,000-25,000
Minor Collector 2 to 3 60' to 80' 25-35 mph 1,000-5,000
Local Street 2 36' to 66' 25-35 mph up to 1,000
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S 272 Street a principal arterial that connects Pacific Highway S to Interstate 5
and SR-516. Study intersections along S 272 include Pacific Highway S, I-5
ramps, and Military Road S.
S 320 Street is a principal arterial with 5 to 7 travel lanes. The roadway connects
I-5 with SR-99 to the west and Military Road/Peasley Canyon Road to the east.
Study intersections along S 320 Street include 1 Avenue S, Pacific Highway S,
21 Avenue S, 23 Avenue S, I-5 ramps, and Military Road.
S 356th Street is a principal arterial that provides a connection between the City
of Tacoma and I-5 and SR-18. Study intersection on S 356th Street includes 21st
Avenue SW, Pacific Highway S, and Enchanted Parkway S.
Right-of-Way
The Federal Way Municipal Code (Section 13-161.11) describes right-of-way as
“…dedicated or conveyed to the public or a unit of government, the primary purpose of
which is the movement of vehicles and/or pedestrians and providing for access to
adjacent parcels, with the secondary purpose of providing space for utility lines and
appurtenances and other devices and facilities benefiting the public.”
The Chapter 3 (Figure III-3) of the City of Federal Way Comprehensive Plan (2003
revision) develops a network of “City Center” roadways that meet the higher level of
amenities for the FWCC planning area (Figure 3). The need for wider sidewalks,
bicycle lanes, street lighting, and street trees resulted in the City designating specific
standards for FWCC roadways. Table 7 lists the required and the typical amounts of
right-of-way found on major roadways within the FWCC planning area.
Table 7. Right-of-Way for Major Area Streets
Roadway Required FWCC
right-of-way Existing right-of-way
Pacific Highway S. (SR-99) 120 feet 100-140 feet
S 324 Street 96 feet 66 feet
S 320 Street 100 feet 100-140 feet
S 316 Street 74 feet 60 feet
S 312 Street 85 feet 60-85 feet
20 Avenue S 60 feet 60 feet
23 Avenue S 85 feet 80-82 feet
Source: King County Assessor 2003
As seen in the table, Pacific Highway S, S 324 Street, S 316 Street, S 312 Street and
23 Avenue S all have inadequate right-of-way. In addition, the FWCC Pan calls for a
number of internal roadways (see Figure 10) to create smaller blocks that will improve
the grid network and improve the access for pedestrians and vehicles. These internal
grid roads noted as Q in Figure 3 require 70 feet of Right of Way with two vehicle lanes,
12 feet of sidewalks, and on street parking. Right-of-way dedication and street
improvements shall be a component of the development submittal phase of a proposed
project within the FWCC.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 12 6/20/2006
Planning & Engineering
Figure 3. Proposed FWCC Street
Network
B
A
Q
One-way
transit road
FWCC Planned Street Section Code
A = 4 lanes + HOV
B = 4 lanes + HOV (City Center)
G = 5 lanes + Bike (City Center)
J = 5 lanes (City Center)
L = 3 lanes + Bike (City Center)
Q = 2 lanes + Parking (City Center Grid Roads)
B
L
G
J
Federal Way City Center Transportation Impact Analysis
6/20/2006 13 Mirai Transportation
Planning & Engineering
Base Year (2004) Volumes
Recent traffic counts were used to establish the 2003-04 base year traffic volumes for
the study (for purposes of the study, 2004 and 2003 volumes were assumed to be
identical since the city performed the 2003 counts in November and December of
2003.). Traffic counts from the City’s database were supplemented by additional counts
conducted in late-2003 through the summer of 2004. For all counts, the reported peak
hour represents the highest single peak hour traffic count taken over a two-hour period.
Appendix D summarizes the traffic counts used in this study. Based on observations of
historical traffic volumes and discussions with City Staff, traffic counts that were older
than 2003, were factored using a historical rate to approximate 2004 count levels. For
PM counts, a TGR of 2.5% per year for 2001 counts and a TGR of 1.1% per year for
2002 counts were used to factor counts to 2004. For AM and Saturday counts, a 2%
per year TGR was used.
The observed peak hour for the three time periods occur between the following hours:
PM peak hour between 4 and 6 p.m.
AM peak hour between 7 and 9 a.m.
Saturday peak hour between 11 a.m. and 1 p.m.
Figures 4 to 6 display the 2004 PM, AM and Saturday peak hour traffic counts.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 14 6/20/2006
Planning & Engineering
Figure 4. Existing PM Volumes
1 2
6
8
21
9
12
20
1615
22
18
2423
25 26 27
5
13
19
3
StudyIntersectionsPMPeakHour 4
Federal Way City Center Transportation Impact Analysis
6/20/2006 15 Mirai Transportation
Planning & Engineering
Figure 4. Existing PM Volumes
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
18 16
1
1
36
2
66
0
21 63
1
0 0 0 10
2
49
3
74 42 18
7
8
26
8
9355004124621786834182
35840679847912705696509562520
1096042482410045026725364
21
5
79
7
41
4
52 0 0 0 57 21
8
48 20
8
59 18
5
20
8
93 6060 39 92
2
26
3
1050
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
17
7
57
5
28
5
31
4
12
0
1
21
0
29
8
15
0
1
1031162711433250
21533037841600
124242119154230
13
3
30
5
13
4
1056 30
1
81
5 88 2550 29
15
3 0 2557
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
21
9
56
0
18
4
36
2
86
8
29
8
58 14
3
43
9
11916241329490245
6621048884102211061465
1293009532435303
26
1
48
9
30
5
3040 18
9
79
6
17
4
3050 72
15
5
42
1
3055
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
80
1
20 41
1
18
9
25
5
17
9
49 10
6
0
13
4
13
9
54
6
23
8
001871787257249235
153014241056931186199572919
653163208216208340116264
0 0 0 3057 92
10
5
88 3064 20
7
92
7
21
3
3350 21
8
50
0
12
4
4028
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
28
6
12
6
5
10
0
13
5
17
7
71 31
0
49
2
18
4
14
3
63
7
99 33
2
0 17
9
3901263678162183113114430205
435415333620725130910061445400639
41715010026610322218342600
20
6
99
1
55 4050 22
0
18
9
16
9
4218 86 27
2
48 4840 83 25
7
19
7
4848 0 0 0 5228
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
24
6
93
0
33 0 11
2
1
15
1402120516
2293021317
28511122726
20
7
37
2
53 5246 28
0
77
1
13 5251
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 16 6/20/2006
Planning & Engineering
Figure 5. Existing AM Volumes
AMPeakHourStudyIntersections 1 2
3
4
21
12 16
22
7
11
Federal Way City Center Transportation Impact Analysis
6/20/2006 17 Mirai Transportation
Planning & Engineering
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
50 32
2
16
7
20
7
7 17
6
0 0 0 78 12
0
54
15314700595788394110
2642111097384631377584681
2619323422800109109
10
0
11
5
6
55
1
52 0 0 0 57 17
4
10 37
0
59 47
6
57
8
15
9
60
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
20
7
38
9
0
8130
00
1450
13
8
52
1 0
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
15
3
24
6
80 61 33
4
10
5
3342324167
7092331006247
11488204123
19
4
52
7
33
8
3028 52
38
0
24
2
3040
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
59
9
8 19
0
00
1350946
444183
0 0 0 3057
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
19
0
30
6
51 9 15
7
60
100617551
335327563142
1695517475
35
1
58
4 69 4050 65 98
16
9
4218
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Figure 5. Existing AM Volumes
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 18 6/20/2006
Planning & Engineering
SaturdayPeakHourStudyIntersections 1 2
8
12 1615
22
13
19
10
14 17
3
4
Figure 6. Existing Saturday Volumes
Federal Way City Center Transportation Impact Analysis
6/20/2006 19 Mirai Transportation
Planning & Engineering
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
57 98
1
31
0
35
3
9 29
2
0 0 0 10
9
20
0
67
107110004523938273
364317811403600358491509
1073672701480020288
19
3
71
6
44
0
52 0 0 0 57 15
2
13 13
5
59 28
4
17
6
72 60
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
14
3
94
5
21
3
48 10
9
6
15
4
225135111138
358472144119
107205232239
23
6
98
1
11
2
2550 24
6
10
6
0
31
0
2750
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
58 31
7
13
6
41
3
85
0
33
0
28
6
23
6
31
6
13
5
14
8
43
5
110124589268500356179349
102097010559451215129214861862
1083605445413136667469
17
0
44
9
43
9
3040 21
1
72
3
18
4
3050 20
6
15
6
15
1
3052 50
15
6
31
7
3055
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
73
0
3 12
6
0 0 0 11
3
10
3
6
22
3
00011312173
1838148710651025161227
6231499030125249
0 0 0 3057 59
4 2 10
2
3058 21
8
89
4
25
6
3350
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
78 12
2
89
7270
508343
125188
10
8
90 18
0
4218
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Figure 6. Existing Saturday Volumes
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 20 6/20/2006
Planning & Engineering
Existing Traffic Operations
Analysis of the PM, AM and Saturday peak hours used the Synchro 6.0 analysis
software to report the Highway Capacity Manual intersection operations for each study
intersection. The City considers intersections to be operating at an acceptable LOS if
operations are LOS E or better and its v/c ratios are less than 1.0 for the critical
movements of the intersection. Table 8 lists the existing LOS operation for the PM, AM
and Saturday peak hour for each of the study intersections applicable to that period.
The reported intersection operations use existing signal timing and phasing plans as
identified by the City of Federal Way. Optimizing the signal phasing and timing could
improve the LOS and v/c results. Appendix E contains the 2004 HCM intersection
analysis sheets for the PM, AM and Saturday peak hours.
Table 8. 2004 Intersection Operations PM Peak, AM Peak, and Saturday Peak
PM Peak AM Peak Saturday Peak Intersection LOS1 V/C2 LOS V/C LOS V/C
1. S 272 St & Pacific Hwy S F 1.29 E 1.01 E 0.97
2. S 272 St & I-5 southbound Ramp E 1.07 C 0.85 C 0.69
3. S 272 St & I-5 northbound Ramp C 0.97 E 1.13 C 0.72
4. S 272 St & Military Rd S F 1.26 F 1.22 D 0.76
5. S 288th St & Pacific Hwy S D 0.89
6. S 288th St & Military Rd S D 0.74
7. S Dash Point Rd & Pacific Hwy S C 0.47
8. S 312 St & Pacific Hwy S E 0.92 E 0.93
9. S 312 St & 28 Av S C 0.673
10. S 316 St & Pacific Hwy S F 1.16
11. SW 320 St & 21 Av SW E 1.00
12. SW 320 St & 1 Av S F 1.06 E 1.01 F 1.18
13. S 320 St & Pacific Hwy S D 0.79 D 0.92
14. S 320 St & 20 Av S F 1.76
15. S 320 St & 23 Av S C 0.85 F 1.09
16. S 320 St & I-5 southbound Ramp C 0.92 C 0.74 D 0.99
17. S 320 St & I-5 northbound Ramp C 0.75
18. S 320 St & Military Rd S D 0.85
19. S 324 St & Pacific Hwy S D 0.68 D 0.88
20. SW 336 St & 21 Av SW E 0.94
21. S 336 St & Pacific Hwy S E 1.15 D 0.70
22. SW 340 St & Hoyt Rd SW C 0.85 B 0.63 B 0.62
23. SW Campus Dr & 1 Av S E 1.05
24. S 348 St & Pacific Hwy S D 0.92
25. SW 356 St & 21 Av SW C 0.75
26. S 356 St & Pacific Hwy S D 0.89
27. S 356 St & Enchanted Pkwy S D 0.78 1LOS reflects the overall operation of the intersection based on the Highway Capacity Manual 2000 methodology 2V/C is the combined volume/capacity of the critical movements of the intersection as identified as the Xc in the HCM
2000 methodology 3Maximum v/c ratio at all-way stop-controlled unsignalized intersection.
Federal Way City Center Transportation Impact Analysis
6/20/2006 21 Mirai Transportation
Planning & Engineering
PM Peak Hour Deficiencies – Six intersections exceed the City’s deficiency threshold
in 2004. These intersections either operate at worse than LOS E and/or have a volume
to capacity ratio equal to or higher than 1.00. Three of the deficient intersections are
located along S 272 Street along the border with the City of Kent. Other deficient
intersection locations include SW 320 Street & 1 Avenue S, S 336 St & Pacific Highway
S, and SW Campus Drive & 1 Avenue S.
AM Peak Hour Deficiencies – Five of the study intersections exceed the City’s
deficiency threshold in 2004. These intersections either operate at worse than LOS E
and/or have a volume to capacity ratio equal to or higher than 1.00. The areas with the
deficient locations include the S 272 Street corridor at the intersections at the I-5
northbound ramp, I-5 southbound ramp, and Military Road S, and the S 320 Street
corridor at the intersections of 1 Avenue S and 21 Avenue SW.
Saturday Peak Hour Deficiencies – Four of the Saturday study intersections exceed
the City’s deficiency threshold in 2004. These intersections either operate at worse
than LOS E and/or have a volume to capacity ratio equal to or higher than 1.00. These
intersections are concentrated around the FWCC area at intersections along Pacific
Highway S and S 320 Street. Weekend retail activity at these locations is likely to
contribute to the high traffic at these intersections.
Parking
The existing number of parking stalls reflects the more auto-oriented development
pattern of the current land uses. Table 9 describes the number of existing parking
spaces in the Federal Way City Center area. Using the three blocks described in Figure
1, Block 1 has 2,960 spaces, Block 2 has 2,760 spaces, and Block 3 has 3,240 for a
total of 8,960 spaces.
Table 9. Existing Parking Supply by Block
Area Parking
Block 1 2,960 stalls
Block 2 2,760 stalls
Block 3 3,240 stalls
Total 8,960 stalls
Source: Jones and Stokes Associates.
Table 10 describes the number of spaces City Code requires for each existing land use.
Approximately 5,900 stalls are required under the parking requirements. When
compared with the existing parking supply, there are approximately 3,000 extra parking
spaces than required by City standards.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 22 6/20/2006
Planning & Engineering
Table 10. Existing Parking Requirements
Land Use Parking Code
Requirement Existing Development Required Parking
Civic Uses Case by case 0 sf 0 stalls
Hotel 1 per room 230 rooms 230 stalls
Office 1 per 300 sf 344,610 sf 1,149 stalls
Other (1) 1 per 1000 sf 14,400 sf 15 stalls
Residential 1.7 per unit 190 units 323 stalls
Retail 1 per 300 sf 1,268,000 sf 4,227 stalls
Total 5,944 stalls
Source: Jones and Stokes Associates.
(1) Parking for Other land use assumed at 1 per 1000 sf.
Collision Data
Review of historical collision data provides an indication of the location and severity of
incidents at intersections and along corridors. Historical analysis is useful in
understanding the typical types of collisions that occur at a particular location; however,
the data may not be indicative of future collision rates or causes. A number of factors
can contribute to collisions including:
Traffic congestion (ability to maneuver)
Driver skills (driver age and experience)
Driver behavior (speeding, aggressiveness, driving while intoxicated)
Roadway geometrics (sight distance)
Weather conditions (rain, glare, snow)
Nature (animals, fallen trees)
Vehicle condition, equipment and maintenance (brakes, tires)
Roadway condition (pavement condition)
Three years (2000-2002) of collision data were analyzed to identify overall trends within
Federal Way. Appendix F summarizes the collision data for study intersections and for
corridors.
High Collision Locations Rate
The City requires the identification of high collision locations, both for corridors and
individual intersections. The Transportation Impact Analysis Guidelines (June 24, 2004
- Page 5) define high collision locations as follows:
A collision rate of more than 1.0 collisions per million entering vehicles at an
intersection.
Federal Way City Center Transportation Impact Analysis
6/20/2006 23 Mirai Transportation
Planning & Engineering
A collision rate of more than 10.0 collisions per million vehicle miles on a
roadway segment.
Table 11 identifies the study intersections that exceed the 1.0 collision per million
entering vehicles. Eighteen of the 32 intersections exceed the 1.0 collision per million
entering vehicles. The highest location is at Military Road S / S 288 Street that
averaged 2.38 collisions per million entering vehicles between 2000 and 2002.
Table 12 identifies the roadway corridors that exceed the City’s standard of 10.0
collisions per million vehicle miles on a roadway segment. All but one of the study
corridors exceeds the 10.0 collisions per million vehicle mile standard.
The City of Federal Way, in general, attributes the majority of collisions to congestion at
roadways and intersections (City of Federal Way Comprehensive Plan, 2003 revision,
Page III-7). The congestion related delay at intersections can result in driver risk-taking
in order to attempt to reduce wait times. Improving vehicle mobility, reducing conflict
points, and reducing vehicle delay may reduce some types of collision along the
corridor. The City traffic engineering department monitors collision data and corrects
roadway and intersection issues that could contribute to higher collision rates at specific
locations.
Table 11. 2000-2002 Intersection Collision Rates
Intersection Total Collisions Collision Rate
Military Rd S / S 288 St 82 2.38
SR 99 / S 312 St 122 2.25
SR 99 / S 348 St 137 2.14
SR 99 / S 272 St 113 1.88
SW 336 St / 21 Av SW 87 1.73
SR 99 / S 320 St 149 1.72
SR 99 / S 316 St 75 1.63
SR 161 / SR 18 136 1.54
Hoyt Rd SW / SW 340 St 31 1.44
SR 99 / S 288 St 79 1.42
S 320 St / southbound I-5 Ramps 84 1.42
SR 99 / S 324 St 76 1.37
SR 99 / S 304 St 58 1.34
S 320 St / 20 Ave S 69 1.29
SR 99 / S Dash Point Rd 61 1.25
S 320 St / 23 Ave S 88 1.22
SR 99 / S 336 St 64 1.1
S 356 St / 21 Av SW 37 1.01
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 24 6/20/2006
Planning & Engineering
Table 12. 2000-2002 Corridor Collision Rates
Corridor Volumes Length Collision Rate
S 348 St (SR 99 to 16 Avenue S) 332 0.21 37.09
S 288 St (SR 99 to Military Road S) 241 0.52 36.56
S 272 St (SR 99 to Military Road S) 492 1 24.3
S 312 St (SR 99 to 28 Avenue S) 229 0.75 24.16
SR 99 (S 272 Street to S 356 Street) 2496 5.24 16.57
S 320 St (SR 99 to Military Road S) 837 1.4 14.06
S 304 St (SR 99 to Military Road S) 88 0.79 11.64
Military Rd (S 272 Street to S 328 Street) 407 3.83 7.2
Future Conditions Analysis
This section describes the methodology and assumptions used to forecast the 2009 and
2014 horizon years used in this analysis. The future forecasts include assumed traffic
growth rates, changes to the roadway network, and planned major developments that
affect the FWCC and study intersections.
Forecasting Model Development
Forecasts of future growth for the PM peak hour used an updated version of the City’s
2002 EMME/2 traffic forecasting model to determine the future traffic volumes on area
roadways and at the study intersections.
The PM peak hour EMME/2 model was calibrated using updated traffic information
including traffic counts, an expanded analysis zone system, and changes in the
roadway network. Traffic counts were updated to bring counts to the 2003/2004 base
year. The model was expanded from a 220-zone to a 250-zone system to include
potential annexation areas of the City. Other street network and land use changes were
also incorporated to bring the model up to 2004 conditions. Appendix B includes the
model validation results.
For the PM peak hour, the EMME/2 model forecasts the expected PM Peak hour traffic
levels based the trip generation and assignment for each of the three land use
alternatives.
Table 13. Assumed Annual Traffic Growth Rates 2004-2009
Analysis Period Annual Growth Rate Source
PM Peak Hour 0.0% to 6.1% FWCC EMME/2 Traffic Model
AM Peak Hour 1.5% City of Federal Way
Saturday Peak Hour 1.1.% City of Federal Way
Federal Way City Center Transportation Impact Analysis
6/20/2006 25 Mirai Transportation
Planning & Engineering
For the PM peak hour, the average traffic growth rate along study intersection
approaches is 3.3% per year with a range within one standard deviation of 0.8% to
5.7%. For the AM peak hour, the City requested the application of a 1.5% background
growth rate to approximate the expected growth between 2004 and 2009 and a 1.1%
growth rate for the Saturday peak hour.
Roadway Improvements Assumptions
Within the study area, there are a number of planned transportation improvements to
increase roadway capacity and to improve mobility. The 2009 baseline forecasts
assumes projects identified in the City of Federal Way’s 2005-2010 Transportation
Improvement Program (Table 14 and Figure 7) and two State Interchange
improvements.2
The 2005-2010 TIP reflects improvements needed to meet the City’s LOS threshold for
operations. City staff develops an annual update of improvements that establishes the
funding needs and priorities for the next six years. All TIP improvements at intersections
and roadway locations were included in the model and the intersection analysis.
Improvements listed in the 2005-2010 TIP include:
Adding HOV lanes
Installing raised median
Installing street illumination
Extending roadways
Adding turn lanes
Installing traffic signal
Installing sidewalks
2 The 2005-2010 TIP was assumed in the analysis of 2009 conditions.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 26 6/20/2006
Planning & Engineering
Table 14. 2005-2010 Transportation Improvement Program
Map
ID Location Description
1 City Center Access Design Study, Environmental analysis
2 SR 99 HOV Lanes Phase 2: S 324 St
- S 340 St
Add HOV lanes, left-turn lanes on 324, 2nd northbound left-turn lane
@ 336, install raised median
3 SR 99 HOV Lanes Phase 3: S 284 St
- SR 509
Add HOV lanes, 2nd southbound left-turn lane and rechannelized
westbound approach for 2nd westbound left-turn lane @ 288, install
raised median, signal @ SR 509 @ Redondo Way S with
interconnect to 11 Pl S
4 S 348 St: 9 Ave S - SR 99 Add HOV lanes, 2nd northbound left-turn lane on SR 99, install
raised median, underground utilities
5 S 320 St @ 1 Ave S Add 2nd northbound, westbound, and southbound left-turn lanes,
westbound right-turn lanes, widen 1 Ave S to 5 lanes to S 316 St
6 S 356 St: 1 Ave S - SR 99 Widen to 5 lanes, bike lanes, sidewalks, illumination
7 S 320 St: 8 Ave S - SR 99 Add HOV lanes, install raised median, underground utilities,
illumination
8 S 348 St @ 1 Ave S Add westbound, southbound right-turn lanes, 2nd eastbound,
westbound left-turn lanes
9 S 336 St @ 1 Wy S Add westbound right-turn lane, signal modifications, extend
southbound left-turn lane
10 10 Ave SW / SW 344 St: SW
Campus Dr - 21 Ave SW Extend 3-lane collectors, sidewalks, street lights
11 1 Ave S: S 320 St - S 330 St Install raised median, improve access at 328th
12 S 320 St @ 20 Ave S Add 2nd left-turn lanes eastbound, westbound
13 21 Ave SW / SW 357 St: SW 356 St -
22nd Ave SW Extend 2-lane collector, signal modifications
14 SR 99 HOV Lanes Phase 4: SR 509 –
S 312 St Add HOV lanes, install raised median
15 SR 18 @ SR 161
Add eastbound, westbound right-turn lanes, 3rd westbound left-turn
lane, 2nd northbound right-turn lane, add 3rd lane on SR 161
southbound to S 352nd St
16 S 336 St @ 9 Ave S Signal modifications
17 SW 312 St: 1 Ave S - SR 509 Widen to 3 lanes, bike lanes, sidewalks, street lights
18 S 320 St @ I-5 Add 2nd left-turn lane, 3rd right-turn lane on southbound off-ramp,
widen S 320 St under crossing to 7 lanes.
19 S 356 St: SR 99 - SR 161 Widen to 5 lanes, bike lanes, sidewalks, illumination
20 S 304 St @ 28 Ave S Add northbound right-turn lane, signal
21 S 352nd St: SR 99 - SR 161 Extend 3 lane principal collector and signal at SR-99
22 SW 320 St @ 21 Ave SW Interconnect to 26 Ave SW with the addition of a 2nd westbound
left-turn lane
23 S 320 St: 1 Ave S - 8 Ave S Add HOV lanes, install raised median Design phase
24 Military Rd S: S Star Lake Rd - S 288
St Widen to 5 lanes, sidewalks, street lights
25 SW 320 St @ 47 Ave SW Install traffic signal
26 S 312 St @ 28 Ave S Add southbound right-turn lane
27 21 Ave S from S 318 St to S 320 St Extends 2-lane grid street with on-street parking
28 SW 336 Wy / SW 340 St: 26 Pl SW -
Hoyt Rd Widen to 5 lanes
29 Westway Neighborhood Add Crime Prevention Street Lights through out the Neighborhood of
Westway
30 S 314 St: 20 Ave S - 23rd Ave S Install sidewalks, ADA ramps, curbs & gutter, pedestrian
improvements
31 1 Ave S: S 292nd St - S 312 St Shoulder improvements
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0
0
5
-
2
0
1
0
T
I
P
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 28 6/20/2006
Planning & Engineering
Transit Services
Federal Way is served by a number of transit providers including King County Metro,
Pierce County Transit, and Sound Transit. Figure 8 indicates the primary transit routes
that serve the planning area.
For more updated information on individual routes please visit the King County Web site
at: http://transit.metrokc.gov/tops/bus/neighborhoods/federal_way.html
In the vicinity of the FWCC, there is frequent transit service with 23 routes serving the
area during weekday hours with service as frequent four times per hour. Midday and
Weekend service levels are lower.
The hub of transit service is the Federal Way Transit Center and Garage located
between S 316 Street and S 317 Street, west of 23 Avenue S. The transit center
includes a HOV direct access ramp for bus and carpool access between the HOV lanes
on I-5 at S 317 Street. The new ramp allows buses and carpools to avoid the congested
S 320 Street/ I-5 interchange. The Transit Center serves the freeway-oriented bus
routes King County Metro Routes 177,194, 197; and Sound Transit Routes 565, 574
and 577. Other transit routes at the Transit Center include King County Metro Routes
174, 181, 182, 183, 187, 565, 574, 577, 901, and 903 as well as Pierce Transit Routes
402, 500, and 501. The other major transit facility within the FWCC vicinity is the S.
Federal Way Park & Ride facility at 23rd Ave S & S 323rd Street. Routes 173, 174,
177, 194, and 196 serve the park and ride facility. Other area park and ride facilities
include the South Federal Way Park & Ride located on S 348th Street and the Twin
Lakes Park and Ride lot located on SW 344th Street. The location and size of all area
park and ride lots is shown Figure 9.
Dart Services are provided on King County Metro routes 901 and 903 for weekday,
Saturday and Sunday Service. Route 949 is Metro Boeing Service at the S. Federal
Way Park & Ride 23rd Ave S & S 323rd Street.
Federal Way City Center Transportation Impact Analysis
6/20/2006 29 Mirai Transportation
Planning & Engineering
Figure 8. Existing Transit Services
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 30 6/20/2006
Planning & Engineering
Figure 9. Park and Ride Lots
900
stalls
500
stalls
40
stalls
30
stalls
5
4
2
5
8
4
4
8
Legend
Number of Lanes 1990
Number of Lanes Today
HOV Lanes
Park and Ride Lots 1990
(with # stalls)
Park and Ride Lots
Today(with # stalls)
X
stalls
X
X
X
stalls
20
stalls
60
stalls
620
stalls
New Loop Ramp
2
7
7
10
4
5
25
stalls
520
stalls
Federal Way City Center Transportation Impact Analysis
6/20/2006 31 Mirai Transportation
Planning & Engineering
Pedestrian Facilities
Figure 10 shows the existing pedestrian facilities within the FWCC planning area.
Sidewalks generally occur along both sides of the street system connecting retail areas
with adjacent neighborhoods and parks. Major impediments to pedestrians include
crossing of major roadways of substantial width and vehicle traffic, such as S 320 Street
at Pacific Highway S. Additionally, existing large blocks with limited connections within
the FWCC are determents to heavy pedestrian usage.
Figure 12 illustrates conceptual locations for new sidewalks (along roadways) and
crosswalk locations within the completed FWCC based on the 2002 City of Federal Way
Comprehensive Plan (Chapter 7). The proposed street network would divide the area’s
large blocks with a new grid network that would increase pedestrian access and
convenience within the FWCC and to surrounding areas. The City of Federal Way
Comprehensive Plan (2003 revision, Chapter 3) includes roadway design standards
specific to the FWCC to provide higher quality pedestrian facilities. These standards
will require roadways to be constructed with 8-12 foot wide sidewalks, street lighting,
and to provide street trees and other amenities such as benches and furniture. The
plan also identifies potential pedestrian over crossing locations on S 320 Street and
Pacific Highway S that would allow improved pedestrian access within the FWCC.
Bicycle Facilities
Figure 11 shows the existing bicycle facilities within and adjacent to the FWCC planning
area. The facilities indicated vary from striped shoulder areas to marked bicycle lanes.
Figure 12 indicates the planned bicycle network within the FWCC planning area. The
network would develop bicycle lanes along S 316 Street, 20 Avenue S, S 324 Street
and Gateway Boulevard connecting to the existing and future park and ride lot facilities,
area parks, and the Bonneville Power Administration utility corridor trail. This level of
development is assumed within the Comprehensive Plan for all three alternatives
considered.
Federal Way City Center Transportation Impact Analysis
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Planning & Engineering
Figure 10. Existing Pedestrian Facilities
Sidewalks 2-sides
Sidewalks 1-side
Source: City of Federal Way Comprehensive Plan - 2002
Federal Way City Center Transportation Impact Analysis
6/20/2006 33 Mirai Transportation
Planning & Engineering
Figure 11. Existing Bicycle Facilities
Striped Shoulder/Bicycle Lane
Federal Way City Center Transportation Impact Analysis
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Planning & Engineering
Figure 12. Future Pedestrian and Bicycle
Facilities
Source: City of Federal Way Comprehensive Plan - 2002
Federal Way City Center Transportation Impact Analysis
6/20/2006 35 Mirai Transportation
Planning & Engineering
Impacts of Alternatives - 2009
This section documents the impact of the FWCC alternatives on the surrounding
roadway network and at study intersections. The section describes the number of trips
associated with the development of the FWCC (Trip Generation), assigns the traffic to
the street network (trip distribution and assignment), and assesses the impact of the
project alternatives on intersection operations, traffic safety, pedestrian and bicycle
systems, and transit operations.
Trip Generation
Trip generation rates for the PM peak hour trip were developed in conjunction with the
EMME2 model and are based on regional studies, local experience and calibration of
the EMME2 model. The Institute of Transportation Engineers (ITE) trip generation rates
(Trip Generation, 7th Edition) were used to estimate trip generation for the AM and
Saturday peak hour Federal Way City Center land use/development scenarios for 2009.
The ITE trip generation rates used for the Federal Way City Center land
use/development scenario analysis are compiled in Table 15. The ITE PM peak hour
rates have been included for comparison only.
Table 15: ITE Trip Generation Rates for Federal Way City Center
Land Use Description:
Single
Family
Housing
Multi
Family
Housing
Retail
Finance,
Insurance,
Real Estate
Others Lodging
ITE Category: SF
Detached Apartment Shopping
Center
General
Office
Industrial
Park Hotel
ITE Code: 210 220 820 710 130 310
independent variable: d.u. d.u. ksf Ksf ksf rooms
Weekday A.M. Peak
average trip gen rate 0.75 0.51 1.03 1.55 0.84 0.56
enter/exit .25/.75 .20/.80 .61/.39 .88/.12 .82/.18 .61/.39
Weekday P.M. Peak
average trip gen rate 1.01 0.62 3.75 1.49 0.86 0.59
enter/exit .63/.37 .65/.35 .48/.52 .17/.83 .21/.79 .53/.47
Saturday Peak
average trip gen rate 0.94 0.52 4.97 0.41 0.35 0.72
enter/exit .54/.46 .54/.46 .52/.48 .54/.46 .32/.68 .56/.44
Source: ITE, Trip Generation, 7th Edition 2004
• “SF” = single-family; “du” = dwelling units; “ksf” = thousands of gross square feet
• PM Trip Rates used for comparison purposes only with EMME/2 model output.
Federal Way City Center Transportation Impact Analysis
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Planning & Engineering
Table 16 summarizes the FWCC growth in trip generation (2004-2009). The PM peak
hour volumes were based on the EMME/2 traffic model and the AM and Saturday use
ITE rates. The estimates for the 2009 No Action (Alt 3) represents around a 10%
growth in peak trips compared with 2004 conditions. Growth in the PM peak hour
between 2004 and 2009 is approximately 40%, compared with 7% for the no action
alternative. The AM peak hour trips for 2009 Alts 1 and 2 represents a 60% increase
compared with 2004 conditions, while the Saturday trips are around 40-45% higher.
Table 16: Summary of Peak Hour Trip Generation for Federal Way City Center
(2004-2009)
Time Period 2004
2009 Alternative 1
increase from
2004
2009 Alternative
2 increase from
2004
2009 Alternative 3
(No Action)
increase from 2004
AM peak hour 2,078 1,220 1,220 233
Saturday peak hour 6,713 2,816 2,816 613
PM peak hour 6,363 2,727 2,522 442
Source: Institute of Transportation Engineers (ITE) Trip Generation, 7th Edition (2004) for AM and Saturday Peak
hour. The PM peak hour trips are based on the EMME/2 model origins and destinations from FWCC TAZs.
Modal Split
Assumption of modal splits are included in the transportation model for the future
alternatives based upon the expected land use, jobs-to-housing balance and availability
of transportation alternatives such as high capacity transit services. Application of these
assumptions lowered the number of vehicle trips that would occur during the peak hour.
No Action (Alternative 3)
The No Action alternative represents the expected growth in the planning area without
the planned FWCC. This alternative would follow existing development patterns.
Roadway and transit improvements listed in the Transportation Improvement Program
(TIP) are assumed to occur under this alternative.
Traffic Growth
Forecasts of the PM peak hour were completed using the EMME/2 transportation
model. The model uses the 2009 land uses to estimate future traffic levels and to
assign the volumes to the roadway network. Use of the model allows traffic to be
redistributed, responding to new capacity from roadway improvements or drivers
seeking new routes in order to avoid intersections with high delays. The EMME/2
forecasted volumes were post-processed using UFOSET software to distribute traffic
volumes at intersections. The software uses existing traffic volumes to evaluate turning
movements and then assigns forecasted trips to these movements and balances
intersection volumes. For the No Action alternative (Alternative 3), the trip generation
and distribution were based on the expected development in the planning area without
the land use and zoning changes assumed in the development of the FWCC. Final PM
Federal Way City Center Transportation Impact Analysis
6/20/2006 37 Mirai Transportation
Planning & Engineering
peak hour volumes included the addition of the Christian Faith Center trips. Appendix
G includes tables that show the PM peak hour post-processed traffic volumes for 2009.
The AM and Saturday peak hour forecasts use the traffic growth factors to estimate an
expected 2009 background traffic. General background growth for the AM peak hours
was assumed at 1.5% per year and for the Saturday peak hours was assumed at 1.1%
per year. The FWCC trip generation for each alternative was assigned and added to
the background traffic, along with the Christian Faith Center volumes, to provide an
estimate of 2009 volumes. Appendix G includes tables that detail the 2009 forecasts
for the AM and Saturday peak hours.
Traffic Volumes
Figures 13-15 show the 2009 traffic volumes for the PM peak, AM peak and Saturday
peak at each of the study intersections. The growth in traffic for the No Action
alternative assumes the scheduled roadway improvements from the 2005-2010 TIP.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 38 6/20/2006
Planning & Engineering
Figure 13. 2009 No Action PM Peak
Turning Volumes
1 2
6
8
21
9
12
20
1615
22
18
2423
25 26 27
5
13
19
3
StudyIntersectionsPMPeakHour 4
Federal Way City Center Transportation Impact Analysis
6/20/2006 39 Mirai Transportation
Planning & Engineering
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
8 18
7
7
27
1
66
2
44 70
0
0 0 0 20
9
56
0
10
6
44 23
7
3
39
5
8049002706202819029229
3562556916031373100281014283125
1689714066360044122126557
15
4
82
0
48
9
52 0 0 0 57 30
1
50 36
1
59 19
8
19
9
70 6060 41 97
0
39
2
1050
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
19
0
50
1
33
5
34
6
16
5
7
29
2
32
0
17
5
0
1241372582063500
35949341054100
153293127250380
15
5
28
1
17
1
1056 29
9
90
2
11
0
2550 59
21
9 0 2557
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
19
6
52
0
15
3
48
4
12
4
4
35
4
75 18
8
43
9
12016739627088189
6831188873108811501543
14835111240145289
29
6
50
6
31
9
3040 22
8
83
6
22
1
3050 93 15
1
40
0
3055
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
10
3
9
26 48
2
20
4
27
5
18
4
71 15
4
5
20
6
16
0
67
6
27
3
002161837777276275
153613551189980233242570969
763161243225189391125300
0 0 0 3057 10
8
12
2 98 3064 21
2
10
9
4
28
3
3350 21
4
54
0
12
2
4028
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
33
6
16
9
9
23
3
14
1
17
6
77 33
7
54
1
15
9
22
8
90
9
16
9
37
0
59 23
5
3022373581171179116120424264
35439936568972615249691399418787
257132992791282571474002136
19
9
12
8
6
40 4050 23
0
18
5
18
4
4218 11
9
32
2 52 4840 90
31
1
24
8
4848 62 18 34 5228
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
34
3
10
7
6
55 0 11
6
7
15
1603433215
3746041625
31918527718
26
7
40
7
83 5246 41
9
72
5 9 5251
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Figure 13. 2009 No Action PM Peak
Turning Volumes
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 40 6/20/2006
Planning & Engineering
AMPeakHourStudyIntersections 1 2
3
4
21
12 16
22
7
11
Figure 14. 2009 No Action AM Peak
Turning Volumes
Federal Way City Center Transportation Impact Analysis
6/20/2006 41 Mirai Transportation
Planning & Engineering
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
54 35
1
18
0
22
4
8 19
0
0 0 0 84 12
9
58
16515900641850424119
2842271183414681406630734
2820825224600117118
10
8
12
4
9
59
5
52 0 0 0 57 18
7
11 40
0
59 51
4
62
3
17
1
60
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
22
3
42
9
0
8760
00
1570
14
9
56
6 0
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
16
5
26
5
87 66 36
0
11
3
3612526072
7712531102273
12399231135
20
9
57
0
38
3
3028 56
40
9
26
8
3040
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
77
0
9 24
0
00
15351038
480197
0 0 0 3057
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
20
8
34
0
10
8
10 16
9
65
114948155
457375621155
1835918781
40
5
64
2
74 4050 70 10
6
18
2
4218
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Figure 14. 2009 No Action AM Peak
Turning Volumes
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 42 6/20/2006
Planning & Engineering
Figure 15. 2009 No Action Saturday Peak
Turning Volumes
SaturdayPeakHourStudyIntersections 1 2
8
12 1615
22
13
19
10
14 17
3
4
Federal Way City Center Transportation Impact Analysis
6/20/2006 43 Mirai Transportation
Planning & Engineering
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
60 10
4
5
32
7
37
5
10 30
8
0 0 0 11
5
21
1
71
113116004774168777
384335857426634378521538
1133902851560021394
20
4
76
6
46
5
52 0 0 0 57 16
1
14 14
5
59 30
1
18
6
77 60
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
15
1
10
2
9
23
8
51 11
9
9
18
2
238150117155
387502152126
124230245255
25
2
10
5
3
14
8
2550 26
0
11
8
1
33
6
2750
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
61 33
5
14
9
44
5
91
5
37
0
31
1
25
6
33
8
14
4
15
6
47
0
116132661299553382190376
11631042119710171311137716242031
1143845749019941372495
18
0
47
4
48
3
3040 22
3
79
5
21
8
3050 23
9
17
2
18
4
3052 56
16
6
33
5
3055
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
78
0
3 13
3
0 0 0 12
1
11
1
7
23
7
00011913079
1996162811561139172242
6641579780132282
0 0 0 3057 62
9 2 10
8
3058 23
0
99
4
30
2
3350
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
82 12
9
94
7674
572367
132199
11
4
95 19
0
4218
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Figure 15. 2009 No Action Saturday Peak
Turning Volumes
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 44 6/20/2006
Planning & Engineering
2009 No Action Traffic Operations
The AM, PM and Saturday study intersections were analyzed using the Synchro 6.0
(Build 6.12) analysis software. Table 17 lists the LOS operation for the PM, AM and
Saturday peak hour for each of the study intersections analyzed for that period. These
intersection operation results assume the completion of the 2005-2010 Transportation
Improvement Program, and existing signal timing and phasing as provided by the City of
Federal Way. Appendix H contains the No Action (Alternative 3) 2009 HCM intersection
analysis sheets for the PM, AM and Saturday peak hours.
Table 17. 2009 Traffic Operations No Action (Alternative 3)
PM Peak AM Peak Saturday Peak Intersection LOS1 V/C2 LOS V/C LOS V/C
1. S 272 St & Pacific Hwy S F 1.10* C 0.71 D 0.77
2. S 272 St & I-5 southbound Ramp F 1.02* C 0.73 C 0.62
3. S 272 St & I-5 northbound Ramp C 0.92 E 1.08* B 0.67
4. S 272 St & Military Rd S F 1.24* F 1.09* D 0.63
5. S 288th St & Pacific Hwy S D 0.82
6. S 288th St & Military Rd S C 0.78
7. S Dash Point Rd & Pacific Hwy S C 0.50
8. S 312 St & Pacific Hwy S E 1.05* D 0.86
9. S 312 St & 28 Av S –
unsignalized B 0.643
10. S 316 St & Pacific Hwy S D 0.89
11. SW 320 St & 21 Av SW D 0.76
12. S 320 St & 1 Av S D 0.81 C 0.77 D 0.85
13. S 320 St & Pacific Hwy S D 0.92 D 0.92
14. S 320 St & 20 Av S E 1.14*
15. S 320 St & 23 Av S D 0.77 F 0.95*
16. S 320 St & I-5 southbound Ramp C 0.78 C 0.68 C 0.84
17. S 320 St & I-5 northbound Ramp B 0.68
18. S 320 St & Military Rd S D 0.96
19. S 324 St & Pacific Hwy S D 0.86 D 0.77
20. SW 336 St & 21 Av SW E 0.99
21. S 336 St & Pacific Hwy S D 1.03* C 0.68
22. SW 340 St & Hoyt Rd SW C 0.63 B 0.52 B 0.55
23. SW Campus Dr & 1 Av S E 0.96
24. S 348 St & Pacific Hwy S D 0.87
25. SW 356 St & 21 Av SW C 0.85
26. S 356 St & Pacific Hwy S C 0.87
27. S 356 St & Enchanted Pkwy S D 0.82
1LOS reflects the overall operation of the intersection based on the Highway Capacity Manual 2000 methodology 2V/C is the combined volume/capacity of the critical movements of the intersection as identified as the Xc in the HCM
2000 methodology. 3Maximum v/c ratio at all-way stop-controlled unsignalized intersection.
*Results from HCM2000 Signals (version 4.1f)
Federal Way City Center Transportation Impact Analysis
6/20/2006 45 Mirai Transportation
Planning & Engineering
2009 No Action Deficiencies
This section describes the 2009 No action alternative deficiencies. The City of Federal
Way defines the minimum acceptable level of service as LOS E or better with a
volume/capacity ratio of less than 1.00 for signalized intersections. Intersections
operating below this threshold are deficient.
PM peak hour Deficiencies – Five intersections exceed the City’s deficiency threshold
in 2009. Deficient intersections are focused along Pacific Highway S and along S 272
Street, where growth in regional traffic is expected to affect intersection operations
during the PM peak hour.
AM peak hour Deficiencies – Two of the study intersections exceed the City’s
deficiency threshold in 2009. The areas with the deficient locations are along S 272
Street at the I-5 northbound ramp and Military Road S intersections.
Saturday peak hour Deficiencies – Two of the Saturday study intersections exceed
the City’s deficiency threshold in 2009 under the No Action Alternative. These
intersections are located in the heart of the FWCC at the intersections of S 320 Street &
20 Avenue S and S 320 Street & 23 Avenue S. Weekend retail activity at these
locations is likely to contribute to the high traffic levels observed at these intersections.
Parking Requirement
Table 18 describes the increase in parking requirements for the No Action alternative
above the existing parking requirements shown in Table 10. These increases assume
full development by the year 2014. A total of 7,485 spaces would be required to meet
the proposed Alternative 3 land uses. The number of spaces represents the City’s
Parking Code requirement and may be reduced through shared parking arrangements
or transportation demand management programs. This reduction could vary from 10%
to 20%.
Table 18. Additional Parking Required for Alternative 3 at Buildout
Land Use Parking Code
Requirement
Proposed
Development Required Parking (1)
Civic Uses Case by case 0 sf 0 stalls
Hotel 1 per room 0 rooms 0 stalls
Office 1 per 300 sf 104,440 sf 348 stalls
Other 1 per 1000 sf 0 sf 0
Residential 1.7 per unit 270 units 459 stalls
Retail 1 per 300 sf 220,270 sf 734 stalls
Total Additional 1,541 stalls
Total Parking 7,485 stalls
Source: Jones and Stokes Associates 2005.
(1) These parking demands may be 10% to 20% less based on shared parking.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 46 6/20/2006
Planning & Engineering
Traffic Safety Impact
As the amount of traffic increases within the area, the probability of traffic collisions
would be expected to increase. The City of Federal Way Comprehensive Plan (2003
revision, Chapter 3, page III-7) identifies that congestion is a primary factor in collision
rates. While the No Action alternative would increase the number of trips at high
collision locations, the number of trips associated with this alternative make up only a
small proportion of the entering trips.
Transit Service Impact
The No Action alternative would support increased transit services and accessibility
described in the City of Federal Way Comprehensive Plan (2002 revision, Chapter 7).
These actions would increase transit service levels and envisions increasing jobs and
housing opportunities within the FWCC to create a transit-oriented community.
Pedestrian Accessibility
The City of Federal Way Comprehensive Plan (2002 revision, Chapter 7) identifies a
number of roadway and pedestrian improvements to occur as part of the development
in the project area (see Figure 12). Improvements include sidewalks and pedestrian
corridors, addition of the grid street system, pedestrian crossings (potentially elevated)
of major roadways and inclusion of pedestrian elements such as street furniture,
covered transit stops, and pedestrian-scale lighting.
Bicycle Mobility Impact
Chapter 7 of the 2002 City of Federal Way Comprehensive Plan (see Figure 12)
identifies bicycle facilities planned for the City Center area. These bicycle facilities
would connect major destinations and would increase the mobility of bicyclists within the
project area. New development under the No Action Alternative would increase
demand for bicycle facilities in the project area. Because development levels are
expected to be less compared to Alternatives 1 or 2, impacts on bicycle facilities
demand would be correspondingly less. Under the No Action Alternative, impacts
associated with individual development proposals in this area would continue to be
individually reviewed through the SEPA review process and decisions about the need
for bicycle facilities would be made on a case-by-case basis.
Proposed Mitigation
Table 19 identifies proposed mitigation for the No Action alternative to meet the City’s or
responsible jurisdiction’s LOS threshold. Intersections along S 272 Street are controlled
by the City of Kent or King County and are mitigated based on the jurisdictions LOS
threshold requirements. Appendix I contains the intersection analysis sheets for the PM,
AM and Saturday peak hours for intersections mitigated under the No Action alternative.
Federal Way City Center Transportation Impact Analysis
6/20/2006 47 Mirai Transportation
Planning & Engineering
Projects identified as CIP are those projects currently identified in the City’s 2009-2020
Capital Improvement Program. Projects identified as TSM are Traffic System
Management improvements identified by the City as part of their City Center Access
Study for 2030 improvements.
Table 19. No Action Proposed Mitigation
PM Peak Hour
Mitigated
ID
Intersection LOS v/c
Improvements
1 S 272 St & Pacific Hwy S F 1.10*No mitigation proposed (1)
2 S 272 St & I-5 southbound Ramp F 1.02*No mitigation proposed (1)
4 S 272 St & Military Rd S F 1.24*No mitigation proposed (2)
8 S 312 St & Pacific Hwy S D 0.95 Add 2nd northbound left turn
lane (CIP 01-05)
21 S 336 St & Pacific Hwy S D 0.92 Optimized signal timing
AM Peak Hour
Mitigated
ID
Intersection LOS v/c
Improvements
3 S 272 St & I-5 northbound Ramp E 1.08*No mitigation proposed (1)
4 S 272 St & Military Rd S F 1.09*No mitigation proposed (2)
SATURDAY Peak Hour
Mitigated
ID
Intersection LOS v/c
Improvements
14 S 320 St & 20 Av S D 0.95 Southbound and northbound right turn lanes
(TSM 2)
15 S 320 St & 23 Av S E 0.92* Add second northbound right turn lane. (TSM 3)
*Results from HCM2000 Signals (version 4.1f)
(1) The City of Kent exempts intersections along Highways of Statewide Significance from their LOS threshold
(2) King County requires mitigation of intersections that receive 30 trips in an hour and 20% of the proposed new trips
and exceeds LOS F. Less than 2% of project trips access the King County intersection of Military Road/272nd Street.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 48 6/20/2006
Planning & Engineering
Alternative 1
This section describes the traffic impacts associated with Alternative 1. The section
describes the trip generation, distribution and assignment, the 2009 turning volumes,
transportation impacts and recommended mitigation.
Trip Generation, Distribution, and Assignment
Alternative 1 focuses development in Blocks 2 and 3 within the Federal Way City
Center. Under this alternative, development would be concentrated along S 320 Street.
PM peak hour trip distribution and assignment were completed using the Federal Way
EMME/2 model. AM and Saturday distribution and assignment follow existing area
traffic patterns. Figures 16 to 18 show the trip distribution for the 2009 under Alternative
1 for the PM, AM and Saturday peak hours.
Traffic Volumes
Figures 19 to 21 show the 2009 turning movement volumes for each study intersection
for Alternative 1 for the PM, AM and Saturday peak hours.
2009 Alternative 1 Traffic Operations
The AM, PM and Saturday study intersections were analyzed using the Synchro 6.0
analysis software. The City considers intersections to be operating at an acceptable
LOS if operations are LOS E or better and its v/c ratios are less than 1.0 for the critical
movements of the intersection. Table 20 lists the LOS operation for the PM, AM and
Saturday peak hour for Alternative 1. These intersection operations are based on
existing signal timing and phasing as provided by the City of Federal Way. Appendix J
contains the Alternative 1 intersection analysis sheets for the 2009 PM, AM and
Saturday peak hours.
Federal Way City Center Transportation Impact Analysis
6/20/2006 49 Mirai Transportation
Planning & Engineering
Figure 16. 2009 Alternative 1 PM Peak Trip
Distribution
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 50 6/20/2006
Planning & Engineering
Figure 17. 2009 Alternative 1 AM Peak Trip
Distribution
Federal Way City Center Transportation Impact Analysis
6/20/2006 51 Mirai Transportation
Planning & Engineering
Figure 18. 2009 Alternative 1 Saturday
Peak Trip Distribution
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 52 6/20/2006
Planning & Engineering
Figure 19. 2009 Alternative 1 PM Peak
Turning Volumes
1 2
6
8
21
9
12
20
1615
22
18
2423
25 26 27
5
13
19
3
StudyIntersectionsPMPeakHour 4
Federal Way City Center Transportation Impact Analysis
6/20/2006 53 Mirai Transportation
Planning & Engineering
Figure 19. 2009 Alternative 1 PM Peak
Turning Volumes
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
7 18
5
5
26
2
66
4
42 69
1
0 0 0 18
7
54
6
10
4
43 23
6
6
39
2
8048002736192799929226
353252692601136497880814323024
1709734016130043824126546
15
5
82
6
48
9
52 0 0 0 57 30
1
51 36
2
59 19
0
20
8
73 6060 41 97
7
39
0
1050
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
19
1
50
2
33
6
34
7
16
5
1
28
9
31
7
17
8
0
1241392602053510
35549740853900
152294127247410
15
5
28
4
17
1
1056 29
9
90
5
10
9
2550 60
21
5 0 2557
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
20
2
53
0
15
7
48
6
12
3
9
35
4
72 19
1
43
4
12317039626885183
6821179871108311531518
14734411139747299
29
3
51
1
31
5
3040 22
9
83
9
22
2
3050 93
14
8
40
7
3055
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
10
1
2
24 46
5
20
6
27
4
18
7
70 15
3
8
20
5
15
9
67
0
27
0
002171837680275274
155613631186967234249571974
742154238219189403125302
0 0 0 3057 10
8
12
3
99 3064 21
2
10
9
7
28
5
3350 21
4
53
9
12
2
4028
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
33
7
17
0
3
23
3
14
1
17
6
77 34
1
54
4
16
3
25
2
88
3
15
8
35
6
59 23
8
3052373580169180122105393263
35740036469172815289751383429794
260133992821262561533442136
19
9
12
8
6
40 4050 23
1
18
4
18
5
4218 11
9
32
2
53 4840 10
3
31
6
24
0
4848 62 18 34 5228
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
35
1
10
0
7
50 0 11
4
8
16
1733334815
3816071526
33017025816
27
8
40
4
78 5246 41
0
71
3 8 5251
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 54 6/20/2006
Planning & Engineering
Figure 20. 2009 Alternative 1 AM Peak
Turning Volumes
AMPeakHourStudyIntersections 1 2
3
4
21
12 16
22
7
11
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6/20/2006 55 Mirai Transportation
Planning & Engineering
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
54 37
6
18
1
23
5
8 19
0
0 0 0 84 13
0
58
16515800641851428119
2852271186414684406633734
2822025224600117121
10
8
12
6
4
59
7
52 0 0 0 57 18
7
11 40
3
59 51
5
62
4
17
1
60
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
22
3
49
5
0
8760
00
1630
15
3
58
4 0
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
16
5
26
5
89 66 36
0
11
4
3662626172
8012621191267
123111220133
20
9
57
7
41
4
3028 56
41
1
29
0
3040
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
79
6
9 24
0
00
15871138
490197
0 0 0 3057
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
22
0
36
8
10
9
10 16
9
65
136938155
457375643159
1906218781
40
5
70
3 74 4050 70
10
6
18
2
4218
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Figure 20. 2009 Alternative 1 AM Peak
Turning Volumes
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 56 6/20/2006
Planning & Engineering
Figure 21. 2009 Alternative 1 Saturday
Peak Turning Volumes
SaturdayPeakHourStudyIntersections 1 2
8
12 1615
22
13
19
10
14 17
3
4
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6/20/2006 57 Mirai Transportation
Planning & Engineering
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
60 11
0
2
32
7
40
2
10 30
8
0 0 0 11
5
21
3
71
113116004774178777
384335857426634378526539
1134172861560021598
20
4
79
8
46
5
52 0 0 0 57 16
1
14 15
2
59 30
2
18
8
78 60
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
15
1
11
5
1
32
6
51 13
5
3
26
2
238183117189
432517152126
159288245274
26
4
11
0
1
29
9
2550 26
0
13
9
8
38
2
2750
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
61 33
5
16
5
48
4
96
9
45
7
34
2
29
6
34
0
15
4
15
7
48
5
116137789367642384198405
13831103140310781368142317992355
1144005750940354774495
18
0
47
4
53
6
3040 22
3
92
9
27
5
3050 31
4
20
9
25
9
3052 61
16
6
33
5
3055
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
84
9
3 13
3
0 0 0 12
7
11
7
5
23
9
00011913684
2144189012491402176246
69315710340132323
0 0 0 3057 62
7 2 10
8
3058 23
0
11
6
7
39
3
3350
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
82 12
9
94
7674
622377
132199
11
4
95 19
0
4218
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Figure 21. 2009 Alternative 1 Saturday
Peak Turning Volumes
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 58 6/20/2006
Planning & Engineering
Table 20. 2009 Alternative 1 Intersection Operations
PM Peak AM Peak Saturday Peak Intersection LOS1 V/C2 LOS V/C LOS V/C
1. S 272 St & Pacific Hwy S F 1.09* D 0.71 D 0.79
2. S 272 St & I-5 southbound Ramp F 1.00* C 0.73 C 0.62
3. S 272 St & I-5 northbound Ramp C 0.92 E 1.09* B 0.67
4. S 272 St & Military Rd S F 1.22* F 1.10* D 0.63
5. S 288th St & Pacific Hwy S D 0.81
6. S 288th St & Military Rd S C 0.78
7. S Dash Point Rd & Pacific Hwy S C 0.52
8. S 312 St & Pacific Hwy S E 1.05* D 0.99
9. S 312 St & 28 Av S B 0.653
10. S 316 St & Pacific Hwy S E 1.05*
11. SW 320 St & 21 Av SW D 0.78
12. S 320 St & 1 Av S D 0.82 D 0.81 D 0.98
13. S 320 St & Pacific Hwy S D 0.91 F 1.00*
14. S 320 St & 20 Av S F 1.35*
15. S 320 St & 23 Av S D 0.76 F 1.04*
16. S 320 St & I-5 southbound Ramp C 0.78 C 0.72 C 0.92
17. S 320 St & I-5 northbound Ramp B 0.72
18. S 320 St & Military Rd S D 0.96
19. S 324 St & Pacific Hwy S D 0.87 D 0.87
20. SW 336 St & 21 Av SW E 0.99
21. S 336 St & Pacific Hwy S D 1.04* C 0.69
22. SW 340 St & Hoyt Rd SW C 0.63 B 0.53 C 0.57
23. SW Campus Dr & 1 Av S E 0.97
24. S 348 St & Pacific Hwy S D 0.80
25. SW 356 St & 21 Av SW C 0.84
26. S 356 St & Pacific Hwy S C 0.84
27. S 356 St & Enchanted Pkwy S D 0.83 1LOS reflects the overall operation of the intersection based on the Highway Capacity Manual 2000 methodology 2V/C is the combined volume/capacity of the critical movements of the intersection as identified as the Xc in the HCM
2000 methodology. 3Maximum v/c ratio at all-way stop-controlled unsignalized intersection.
*Results from HCM2000 Signals (version 4.1f)
2009 Alternative 1 Deficiencies
This section describes the 2009 Alternative 1 deficiencies. The City of Federal Way
defines the minimum acceptable level of service as LOS E or better with a
volume/capacity ratio of less than 1.00 for signalized intersections. Intersections
operating below this threshold are deficient
Federal Way City Center Transportation Impact Analysis
6/20/2006 59 Mirai Transportation
Planning & Engineering
PM Peak Hour Deficiencies – Five intersections exceed the City’s deficiency threshold
in 2009 for Alternative 1. Deficient intersections are focused along S 272 Street and
Pacific Highway S, where growth in regional traffic is expected to affect intersection
operations during the PM peak hour.
AM Peak Hour Deficiencies – Two of the study intersections exceed the City’s
deficiency threshold in 2009 for Alternative 1. The deficient intersections are located at
I-5 northbound Ramp and Military Road S along S 272 Street.
Saturday Peak Hour Deficiencies – Four of the Saturday study intersections exceed
the City’s deficiency threshold in 2009 for Alternative 1. These intersections are
focused around the FWCC area, at S 316 Street and S 320 Street on Pacific Highway S,
and at the intersections at 20 Avenue S and 23rd Avenue S on S 320 Street. Weekend
retail activity at these locations is likely to contribute to the high traffic at these
intersections.
Parking Requirements
Table 21 describes the increase in parking requirement for the Alternative 1 above the
existing code requirements shown in Figure 10. These increases assume full
development by the year 2014. A total of 11,486 spaces would be required to meet
existing and future lane uses. The parking requirements estimate the number of spaces
required for the proposed mix of uses assumed for Alternative 1. Compared with
Alternative 3, the City’s parking code would require approximately 4,000 additional
spaces for Alternative 1. These spaces may be provided on the site or as part of
parking garages assumed as part of the FWCC development. The actual parking
requirement for an individual development may be reduced through shared parking
arrangements or transportation demand management programs. This reduction could
vary from 10% to 20%.
Table 21. Additional Parking Required for Alternative 1 at Buildout
Land Use Parking Code
Requirement
Proposed
Development
Additional Required
Parking (1)
Increase over
Alternative 3
Civic Uses Case by case 100,000 sf Unknown Unknown
Hotel 1 per room 600 rooms 600 stalls 600 stalls
Office 1 per 300 sf 350,000 sf 1,167 stalls 819 stalls
Other 1 per 1000 sf 0 sf 0 stalls 0 stalls
Residential 1.7 per unit 750 units 1,275 stalls 816 stalls
Retail 1 per 300 sf 750,000 sf 2,500 stalls 1,766 stalls
Total Additional 5,542 stalls 4,001 stalls
Total Parking 11,486 stalls
Source: Jones and Stokes Associates, 2005.
These parking demands may be 10% to 20% less based on shared parking.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 60 6/20/2006
Planning & Engineering
Traffic Safety Impact
As the amount of traffic increases within the area, the probability of traffic collisions
would be expected to increase. The City of Federal Way Comprehensive Plan (2003
revision, Chapter 3, page III-7) identifies that congestion is a primary factor in collision
rates. Alternative 1 would increase the number of trips at high collision locations, the
number of trips associated with this alternative make up only a small proportion of the
entering trips. In addition, roadway improvements designed to reduce congestion may
lower congestion-associated collisions.
Transit Service Impact
Alternative 1 would provide a high level of urban development and amenities in
immediate proximity to the new 312th Street Transit Center. Under the alternative, a
large proportion of development would be concentrated along S 320 Street, near the
transit center, providing a high number of potential transit users who may be able to
walk to the Transit Center. Expected residents of the FWCC would likely include transit
users and may result in increased ridership demand at the transit center.
Pedestrian Accessibility
The City of Federal Way Comprehensive Plan (2002 revision, Chapter 7) identifies a
number of roadway and pedestrian improvements to occur as part of development of
the project area (see Figure 12). Alternative 1 concept of a pedestrian-oriented, mixed-
use center would encourage use of these facilities, as residents would be able to easily
access retail and service locations within a short walking distance.
Bicycle Mobility Impact
Chapter 7 of the 2002 City of Federal Way Comprehensive Plan (see Figure 12)
identifies bicycle facilities planned for the City Center area. These bicycle facilities
would connect major destinations and would increase the mobility of bicyclists within the
project area. New development under Alternative 1 would increase the demand for
bicycle facilities in the project area. Impacts associated with development permitted
through the Planned Action Ordinance would be addressed as described in the
Additional Mitigation described on page 94.
Proposed Mitigation
Alternative 1 would increase the density and activity within the FWCC core. The
increased density could increase traffic congestion; however, these increases may be
offset by reduced vehicle travel demand resulting from mixed-use development,
improvements to pedestrian facilities, and improved transit services. Based on the LOS
analysis, the following additional improvements (those beyond improvements identified
for Alternative 3) would be required under Alternative 1 to meet the City’s LOS
threshold. Table 22 identifies the intersection location, the LOS and v/c ratio, and
Federal Way City Center Transportation Impact Analysis
6/20/2006 61 Mirai Transportation
Planning & Engineering
suggested mitigation for each intersection. Appendix K contains the intersection
analysis sheets for the 2009 PM, AM and Saturday peak hours for intersections
mitigated in Alternative 1.
Table 22. Alternative 1 Mitigation
PM PEAK 2009 - Alternative 1
Mitigated
ID Intersection LOS v/c Improvements over Alt 3
1 S 272 St & Pacific Hwy S F 1.09* No mitigation proposed (1)
2 S 272 St & I-5 southbound Ramp E 1.00* No mitigation proposed (1)
4 S 272 St & Military Rd S F 1.22* No mitigation proposed (2)
8 S 312 St & Pacific Hwy S D 0.95 Alternative 3 mitigation (CIP 01-05)
21 S 336 St & Pacific Hwy S D 0.93 Optimize signal timing
AM Peak Hour 2009 - Alternative 1
Mitigated
ID
Intersection LOS v/c
Improvements
3 S 272 St & I-5 northbound Ramp E 1.09*No mitigation proposed (1)
4 S 272 St & Military Rd S F 1.10*No mitigation proposed (2)
SATURDAY 2009 - Alternative 1
Mitigated
ID Intersection LOS v/c Improvements over Alt 3
10 S 316 St & Pacific Hwy S D 0.92 Eastbound right turn lane (TSM 12)
13 S 320 St & Pacific Hwy S E 0.96 Northbound right turn lane
14 S 320 St & 20 Av S D 0.99 Alternative 3 mitigation (TSM 2)
15 S 320 St & 23 Av S E 0.92 Alternative 3 mitigation (TSM 3) plus westbound right
turn lane
*Results from HCM2000 Signals (version 4.1f)
(1) The City of Kent exempts intersections along Highways of Statewide Significance from their LOS threshold
(2) King County requires mitigation of intersections that receive 30 trips in an hour and 20% of the proposed new trips
and exceeds LOS F. Less than 2% of project trips access the King County intersection of Military Road/272nd Street.
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 62 6/20/2006
Planning & Engineering
Alternative 2
This section describes the traffic impacts associated with Alternative 2. The section
describes the trip generation, distribution and assignment, the 2009 turning volumes,
transportation impacts and recommended mitigation.
Trip Generation, Distribution, and Assignment
Alternative 2 accounts for the same level of development within the Federal Way City
Center as Alternative 1, but spreads this development throughout the FWCC area. The
trip distribution and assignment were completed using the City’s EMME/2 model. AM
and Saturday distribution and assignment follow existing area traffic patterns. Figures
22 to 24 show the trip distribution for the 2009 under Alternative 2 for the PM, AM and
Saturday peak hours.
Traffic Volumes
Figures 25 to 27 show the 2009 turning movement volumes for each study intersection
for Alternative 2 for the PM, AM and Saturday peak hours. Traffic volumes for the PM
peak hour are based on the model results. AM and Saturday volumes were estimated
based upon an annual growth rate.
2009 Alternative 2 Traffic Operations
The AM, PM and Saturday study intersections were analyzed using the Synchro 6.0
(Build 6.12) analysis software. The City considers intersections to be operating at an
acceptable LOS if operations are LOS E or better and its v/c ratios are less than 1.0 for
the critical movements of the intersection. Table 23 lists the LOS operation for the PM,
AM and Saturday peak hour for Alternative 2. These intersection operations are based
on existing signal timing and phasing as provided by the City of Federal Way. Appendix
L contains the Alternative 2 intersection analysis sheets for the 2009 PM, AM and
Saturday peak hours.
Federal Way City Center Transportation Impact Analysis
6/20/2006 63 Mirai Transportation
Planning & Engineering
Figure 22. 2009 Alternative 2 PM Peak
Trip Distribution Volumes
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 64 6/20/2006
Planning & Engineering
Figure 23. 2009 Alternative 2 AM Peak
Trip Distribution
Federal Way City Center Transportation Impact Analysis
6/20/2006 65 Mirai Transportation
Planning & Engineering
Figure 24. 2009 Alternative 2 Saturday
Peak Trip Distribution
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 66 6/20/2006
Planning & Engineering
Figure 25. 2009 Alternative 2 PM Peak
Turning Volumes
1 2
6
8
21
9
12
20
1615
22
18
2423
25 26 27
5
13
19
3
StudyIntersectionsPMPeakHour 4
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6/20/2006 67 Mirai Transportation
Planning & Engineering
Figure 26. 2009 Alternative 2 PM Peak
Turning Volumes
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
8 18
7
1
26
6
65
5
44 70
1
0 0 0 21
0
55
8
10
5
43 23
5
2
39
2
81490026462831110230228
3542576856101375102279914573124
1709604066560043822326546
15
8
82
6
48
4
52 0 0 0 57 30
9
51 37
5
59 19
4
21
5
67 6060 41 97
6
38
9
1050
S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
18
6
49
7
33
2
34
7
16
3
3
29
1
31
5
17
7
0
1231402592063520
35149341154500
150298126247410
15
3
28
4
17
1
1056 30
0
90
1
11
0
2550 60
21
4 0 2557
SW 320 St & 21 Av SSW 320 St & 1 Av SS 320 St & Pacific Hwy SS 320 St & 20 Av SS 320 St & 23 Av S
20
1
52
0
15
5
48
7
12
2
6
35
2
72 18
3
43
0
12316939726884181
6831183869108611421526
14634111139445286
29
4
51
1
31
3
3040 22
9
83
5
22
0
3050 93
14
7
40
4
3055
S 320 St & I-5 SB -320 RampS 320 St & 320 - I-5 NB RampS 320 St & Military Rd SS 324 St & Pacific Hwy SSW 336 St & 21 Av SW
10
1
7
25 47
2
20
6
27
4
18
5
69 15
2
1
20
5
16
1
67
5
27
4
002181827679276274
154713591193973235243571972
738155241220188398124298
0 0 0 3057 10
9
12
3
99 3064 21
0
10
9
3
28
8
3350 21
4
53
9
12
2
4028
S 336 St & Pacific Hwy SSW 340 St & Hoyt Rd SWSW Campus Dr & 1 Av SS 348 St & Pacific Hwy SSW 356 St & 21 Av SW
33
9
16
8
5
23
0
14
1
17
6
77 33
9
54
1
16
0
24
5
88
0
17
2
36
3
59 23
5
3082363581172180118112399265
35340136569072915199841380423797
260131992811282551413542136
20
0
12
8
3
38 4050 23
0
18
5
18
5
4218 11
7
32
0
52 4840 95 31
3
24
9
4848 62 18 34 5228
S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
36
2
99
3
49 0 11
6
0
16
1763233815
3746011525
32716125917
28
2
40
0
75 5246 40
8
72
1 8 5251
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Federal Way City Center Transportation Impact Analysis
Mirai Transportation 68 6/20/2006
Planning & Engineering
AMPeakHourStudyIntersections 1 2
3
4
21
12 16
22
7
11
Figure 26. 2009 Alternative 2 AM Peak
Turning Volumes
Federal Way City Center Transportation Impact Analysis
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Planning & Engineering
S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
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S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
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S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
21 3 4 5
76 8 9 10
1211 13 14 15
1716 18 19 20
2221 23 24 25
2726
Figure 26. 2009 Alternative 2 AM Peak
Turning Volumes
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SaturdayPeakHourStudyIntersections 1 2
8
12 1615
22
13
19
10
14 17
3
4
Figure 27. 2009 Alternative 2 Saturday
Peak Turning Volumes
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S. 272 St & Pacific Hwy SS. 272 St & I-5 SB RampS. 272 St & I-5 NB RampS. 272 St & Military Rd SS 288 St & Pacific Hwy S
60 10
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S 288 St & Military Rd SS Dash Point Rd & Pacific Hwy SS 312 St & Pacific Hwy SS 312 St & 28 Av SS 316 St & Pacific Hwy S
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S 356 St & Pacific Hwy SS 356 St & Enchanted Pkwy S
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2221 23 24 25
2726
Figure 27. 2009 Alternative 2 Saturday
Peak Turning Volumes
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Table 23. 2009 Alternative 2 Intersection Operations
PM Peak AM Peak Saturday Peak Intersection LOS1 V/C2 LOS V/C LOS V/C
1. S 272 St & Pacific Hwy S F 1.09* D 0.71 D 0.75
2. S 272 St & I-5 southbound
Ramp F 1.03* C 0.73 C 0.62
3. S 272 St & I-5 northbound
Ramp C 0.85 E 1.09* B 0.67
4. S 272 St & Military Rd S F 1.27* F 1.10* D 0.63
5. S 288th St & Pacific Hwy S D 0.81
6. S 288th St & Military Rd S C 0.77
7. S Dash Point Rd & Pacific
Hwy S C 0.52
8. S 312 St & Pacific Hwy S E 1.05* D 0.98
9. S 312 St & 28 Av S B 0.653
10. S 316 St & Pacific Hwy S E 1.06*
11. SW 320 St & 21 Av SW D 0.78
12. S 320 St & 1 Av S D 0.81 D 0.81 D 0.97
13. S 320 St & Pacific Hwy S D 0.91 F 1.01*
14. S 320 St & 20 Av S F 1.47*
15. S 320 St & 23 Av S D 0.76 F 1.05*
16. S 320 St & I-5 southbound
Ramp C 0.78 C 0.71 C 0.94
17. S 320 St & I-5 northbound
Ramp B 0.76
18. S 320 St & Military Rd S D 0.96
19. S 324 St & Pacific Hwy S D 0.86 D 0.87
20. SW 336 St & 21 Av SW E 0.99
21. S 336 St & Pacific Hwy S D 1.05* C 0.69
22. SW 340 St & Hoyt Rd SW C 0.63 B 0.53 C 0.57
23. SW Campus Dr & 1 Av S E 0.96
24. S 348 St & Pacific Hwy S D 0.80
25. SW 356 St & 21 Av SW C 0.84
26. S 356 St & Pacific Hwy S C 0.83
27. S 356 St & Enchanted Pkwy S D 0.82 1LOS reflects the overall operation of the intersection based on the Highway Capacity Manual 2000 methodology 2V/C is the combined volume/capacity of the critical movements of the intersection as identified as the Xc in the HCM
2000 methodology. 3Maximum v/c ratio at all-way stop-controlled unsignalized intersection.
*Results from HCM2000 Signals (version 4.1f)
2009 Alternative 2 Deficiencies
This section describes the 2009 Alternative 2 deficiencies. The City of Federal Way
defines the minimum acceptable level of service as LOS E or better with a
volume/capacity ratio of less than 1.00 for signalized intersections. Intersections
operating below this threshold are deficient.
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PM Peak Hour Deficiencies – Five intersections exceed the City’s deficiency threshold
in 2009 for Alternative 2. Deficient intersections are focused along S 272 Street and
Pacific Highway S, where growth in regional traffic is expected to affect intersection
operations during the PM peak hour.
AM Peak Hour Deficiencies – Two of the study intersections exceed the City’s
deficiency threshold in 2009 for Alternative 2. The deficient intersections are located at
I-5 northbound Ramp and Military Road S along S 272 Street.
Saturday Peak Hour Deficiencies – Four of the Saturday study intersections exceed
the City’s deficiency threshold in 2009 for Alternative 2. These intersections are
focused around the FWCC area, at S 316 Street and S 320 Street on Pacific Highway S,
and at the intersections at 20 Avenue S and 23rd Avenue S on S 320 Street. Weekend
retail activity at these locations is likely to contribute to the high traffic at these
intersections.
Parking Requirement
Table 24 describes the increase in parking requirement for the Alternative 2 above the
existing code requirements shown in Figure 10. A total of 11,486 spaces would be
required to meet existing and future lane uses (same as Alternative 1). The parking
requirements estimate the number of spaces required for the proposed mix of uses
assumed for Alternative 2. Compared with Alternative 3, the City’s parking code would
require approximately 4,000 additional spaces for Alternative 2. These spaces may be
provided on the site or as part of parking garages assumed as part of the FWCC
development. The actual parking requirement for an individual development may be
reduced through shared parking arrangements or transportation demand management
programs. This reduction could vary from 10% to 20%.
Table 24. Additional Parking Required for Alternative 2 at Buildout
Land Use Parking Code
Requirement
Proposed
Development
Additional Required
Parking (1)
Increase over
Alternative 3
Civic Uses Case by case 100,000 sf Unknown Unknown
Hotel 1 per room 600 rooms 600 stalls 600 stalls
Office 1 per 300 sf 350,000 sf 1,167 stalls 819 stalls
Other 1 per 1000 sf 0 sf 0 stalls 0 stalls
Residential 1.7 per unit 750 units 1,275 stalls 816 stalls
Retail 1 per 300 sf 750,000 sf 2,500 stalls 1,766 stalls
Total Additional 5,542 stalls 4,001 stalls
Total Parking 11,486 stalls
Source: Jones and Stokes Associates, 2005.
(1)These parking demands may be 10% to 20% less based on shared parking.
Traffic Safety Impact
As the amount of traffic increases increase within the area, the probability of traffic
collisions would be expected to increase. The City of Federal Way Comprehensive
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Plan (2003 revision, Chapter 3, page III-7) identifies that congestion is a primary factor
in collision rates. Alternative 2 would increase the number of trips at high collision
locations, the number of trips associated with this alternative make up only a small
proportion of the entering trips. Improvements associated with traffic improvement
would reduce congestion and the congestion-associated collisions.
Transit Service Impact
Alternative 2 would provide a high level of urban development and amenities in area
near the new 312th Street Transit Center. Under the alternative, development would
occur throughout the FWCC, providing a high number of potential transit users who may
walk to the Transit Center. Expected residents of the FWCC would likely include transit
users.
Pedestrian Accessibility
The City of Federal Way Comprehensive Plan (2002 revision, Chapter 7) identifies a
number of roadway and pedestrian improvements to occur as part of future
development (see Figure 12). Alternative 2 concept of a pedestrian-oriented, mixed-use
center would encourage use of these facilities, as residents would be able to easily
access retail and service locations within a short walking distance.
Bicycle Mobility Impact
Chapter 7 of the 2002 City of Federal Way Comprehensive Plan (see Figure 12)
identifies bicycle facilities planned for the City Center area. These bicycle facilities
would connect major destinations and would increase the mobility of bicyclists within the
project area. New development under Alternative 2 would increase the demand for
bicycle facilities in the project area. Impacts associated with development permitted
through the Planned Action Ordinance would be addressed as described in the
Additional Mitigation described on page 94.
Proposed Mitigation
Alternative 2 would increase the density and activity within the FWCC core, but would
spread out the impact throughout the FWCC area. The increased density could increase
traffic congestion; however, these increases may be offset by reduced vehicle travel
demand resulting from mixed-use development, improvements to pedestrian facilities,
and improved transit services. Based on the LOS analysis, the following additional
improvements (those beyond improvements identified for Alternative 3) would be
required under Alternative 2 to meet the City’s LOS threshold. Table 25 identifies the
intersection location, the LOS and v/c ratio and the suggested mitigation for each
intersection. Appendix M contains the intersection analysis sheets for the 2009 PM, AM
and Saturday peak hours for intersections mitigated in Alternative 2.
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Table 25. Alternative 2 Mitigation
PM PEAK 2009 - Alternative 2
Mitigated
ID Intersection LOS v/c Improvements over Alt 3
1 S 272 St & Pacific Hwy S F 1.09* No mitigation proposed (1)
2 S 272 St & I-5 southbound Ramp F 1.00* No mitigation proposed (1)
4 S 272 St & Military Rd S F 1.22* No mitigation proposed (2)
8 S 312 St & Pacific Hwy S D 0.95 Alternative 3 mitigation (CIP 01-05)
21 S 336 St & Pacific Hwy S D 0.93 Optimize signal timing
AM Peak Hour 2009 - Alternative 2
Mitigated
ID
Intersection LOS v/c
Improvements
3 S 272 St & I-5 northbound Ramp E 1.09*No mitigation proposed (1)
4 S 272 St & Military Rd S F 1.10*No mitigation proposed (2)
SATURDAY 2009 - Alternative 2
Mitigated
ID Intersection LOS v/c Improvements over Alt 3
10 S 316 St & Pacific Hwy S C 0.92 Eastbound right turn lane (TSM 12)
13 S 320 St & Pacific Hwy S E 0.94*Northbound right turn lane
14 S 320 St & 20 Av S D 0.98 Alternative 3 mitigation (TSM 2)
15 S 320 St & 23 Av S E 0.93 Alternative 3 mitigation (TSM 3) plus westbound right
turn lane
*Results from HCM2000 Signals (version 4.1f)
(1) The City of Kent exempts intersections along Highways of Statewide Significance from their LOS threshold
(2) King County requires mitigation of intersections that receive 30 trips in an hour and 20% of the proposed new trips
and exceeds LOS F. Less than 2% of project trips access the King County intersection of Military Road/272nd Street.
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2014 Forecasts
The 2014 forecasts are intended to provide an initial look at the traffic operations and
impacts of each of the FWCC alternatives. This analysis will describe the forecasting
methodology, describe expected roadway volumes for Alternatives 1-3 and identify
locations where traffic growth may impact City’s intersections. Because this is a longer
range forecast, only roadway volumes are reported. In addition, specific mitigation
measures are not included. The City has proposed to conduct a 2009 analysis of
building construction and traffic growth to verify the status of the FWCC development
and to update the traffic forecasts for 2014.
Forecast Methodology
Forecasts of the PM peak hour were completed using the EMME/2 transportation
model. The model compares the 2009 and 2014 land uses to estimate future traffic
levels and to assign the volumes to the roadway network. The model was used to
identify the 2009-2014 growth in background traffic and the 2009-2014 growth in trips
from the FWCC site.
The AM and Saturday peak hour forecasts use the 2004-2009 traffic growth factors to
estimate an expected 2014 background traffic. General background growth for the AM
peak hour is assumed at 1.5% per year and 1.1% for the Saturday peak hour. The
FWCC trip generation for each alternative was assigned and added to the 2009 base
volumes and 2009-2014 background growth traffic to provide an estimate of 2014
volumes. Appendix N includes the 2014 forecasted volumes for the PM, AM and
Saturday peak hours.
Roadway Improvement Assumptions
Only one roadway improvement project based on the CIP was added to the baseline
model for 2014. This project would construct a roadway connection between S 312th
Street at 14th Avenue S and S 320th Street at 11th Place S.
Trip Generation
Table 26 summarizes the growth in trip generation from 2009 to 2014. The 2014
forecasts include two options for a “Civic Center” resulting in a range of values for the
trip generation. The first civic center option would develop a convention center facility
that would be primarily be used for special events, expositions, and activities. The
second civic center option would be a daily-use facility, which would feature daily
activities and programs. The second option would be expected to have higher daily and
peak hour trip generation.
The estimates of growth for the 2009-2014 No Action (Alt 3) represents 70-90% of the
growth expected from 2004-2009 as shown in Table 16. Alternatives 1 and 2 have the
same trip generation. The range of trip generation reflects the two options for the Civic
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Center land use described above. The PM and Saturday peak hour trip growth is
slightly lower than the growth during the 2004- 2009 time period. The AM trips
represent 77% of the previous five-year growth.
Table 26: Summary of Trip Generation for Federal Way City Center (2010-2014)
Time Period
2014 Alternative 1
increase from
2009 Alt 1*
2014 Alternative 2
increase from
2009 Alt 2*
2014 Alternative 3
increase from
2009 Alt 3
AM peak hour 919-1,073 919-1,073 214
Saturday peak hour 2,537-2,552 2,537–2,552 437
PM peak hour 2,360 – 2,370 2,360–2,370 419
* Range of trip generation reflects two options for the Civic Center land use.
Source: ITE Trip Generation, 7th Edition
Trip Distribution and Assignment
Trip distribution and assignment were assumed to remain similar to 2009. The PM peak
hour distribution was calculated using the EMME/2 model. The AM and Saturday trip
distribution used the 2009 distribution of trips to assign the 2014 traffic growth on the
network.
2014 No Action Traffic Volumes
Figures 28 to 30 show the expected 2014 traffic volumes on selected roadways for the
No Action Alternative (Alternative 3) for the PM, AM and Saturday peak hours. The
volumes indicate higher traffic levels on area streets and roadways that may result in
increased congestion at major intersections.
The majority of traffic growth would be from 2009-2014 background growth associated
with regional traffic and future development not associated with the FWCC. The FWCC
No Action alternative adds only low levels of traffic to area roadways. Based on the trip
generation, approximately 420 new PM peak hour trips would be added to area
roadways. Impacts from the FWCC planning area are generally low, with the added
2009-2014 FWCC traffic growth accounting for less than 5% of traffic volumes at
intersections.
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Figure 28. 2014 Volumes – PMPeak Hour
–No Action
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Figure 29. 2014 Volumes –AM Peak Hour
–No Action
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Figure 30. 2014 Volumes –Saturday Peak
Hour –No Action
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2014 Alternative 1 Traffic Volumes
Figures 31 to 33 show the expected 2014 traffic volumes on selected roadways for the
Alternative 1 during the PM, AM and Saturday peak hours. Because the land uses are
concentrated along the S 320 Street corridor, the project trips generated for Alternative
1 would impact primarily intersections along this corridor.
PM Peak Hour
During the PM peak hour, the primary impact of Alternative 1 would be on roadways
near and within the FWCC planning area. During the PM peak hour, the alternative
would add nearly 2,400 total trips to area roadways, concentrated on S 320 Street and
Pacific Highway S. The following intersections would be impacted by the alternative:
• S 320 St & Pacific Hwy S (1260 additional trips)
• S 336 St & Pacific Hwy S (910 additional trips)
• S 348th St & Pacific Hwy S (870 additional trips)
• S 324 St & Pacific Hwy S (780 additional trips)
• S 320 St & Military Rd S (750 additional trips)
• S 320 St & 23 Av S (740 additional trips)
AM Peak Hour
During the AM peak hour, Alternative 1 volumes would be on roadways near and within
the FWCC planning area. During the AM peak hour, nearly 1,100 trips to area roadways
would be added, concentrated on roads near the FWCC, especially on S 320 Street.
Intersections that would see the greatest impact from the alternative would be:
• S 320 St & I-5 southbound - 320 Ramp (510 additional trips)
• S 320 St & 1 Av S (380 additional trips)
• S 336 St & Pacific Hwy S (370 additional trips)
• S 272 St & Pacific Highway S (340 additional trips)
Saturday Peak Hour
Alternative 1 would add 2,500 trips to area roadways, mainly within and adjacent to the
FWCC. The following intersections would see the greatest impact from the alternative
during the Saturday peak hour:
• S 320 St & Pacific Hwy S (1370 additional trips)
• S 320 St & 20 Av S (1220 additional trips)
• S 320 St & 23 Av S (980 additional trips)
• S 312 St & Pacific Hwy S (910 additional trips)
• S 320 St & I-5 southbound - 320 Ramp (870 additional trips)
• S 316 St & Pacific Hwy S (850 additional trips)
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Figure 31. 2014 Volumes –PM Peak Hour
–Alternative 1
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Figure 32. 2014 Volumes –AM Peak Hour
–Alternative 1
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Figure 33. 2014 Volumes –Saturday Peak
Hour –Alternative 1
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2014 Alternative 2 Traffic Volumes
Figures 34 to 36 show the expected 2014 traffic volumes on selected roadways for the
Alternative 2 for the PM, AM and Saturday peak hours. The project trips generated for
Alternative 2 are assumed identical to Alternative 1, but assume that development is
spread throughout the FWCC area.
PM Peak Hour
During the PM peak hour, the primary impact of Alternative 2 would be on roadways
near and within the FWCC planning area. During the PM peak hour, the alternative
would add nearly 2,400 trips to area roadways, concentrated on roads near the FWCC.
The following intersections would see the greatest impact from the alternative:
• S 320 St & Pacific Hwy S (1180 additional trips)
• S 336 St & Pacific Hwy S (880 additional trips)
• S 348th St & Pacific Hwy S (860 additional trips)
• S 324 St & Pacific Hwy S (740 additional trips)
• S 320 St & Military Rd S (700 additional trips)
• S 320 St & 23 Av S (670 additional trips)
AM Peak Hour
During the AM peak hour, Alternative 2 volumes would be on roadways near and within
the FWCC planning area. During the AM peak hour, the alternative would add nearly
1,100 trips to area roadways, concentrated on roads near the FWCC. Intersections that
would see the greatest impact from the alternative would be:
• S 320 St & I-5 southbound - 320 Ramp (520 additional trips)
• S 320 St & 1 Av S (380 additional trips)
• S 336 St & Pacific Hwy S (370 additional trips)
• S 272 St & Pacific Highway S (340 additional trips)
Saturday Peak Hour
Alternative 2 would add 2,500 trips to area roadways, mainly within and adjacent to the
FWCC. The following intersections would see the greatest impact from the alternative
during the Saturday peak hour:
• S 320 St & Pacific Hwy S (1370 additional trips)
• S 320 St & 20 Av S (1160 additional trips)
• S 320 St & 23 Av S (1010 additional trips)
• S 320 St & I-5 southbound - 320 Ramp (910 additional trips)
• S 312 St & Pacific Hwy S (890 additional trips)
• S 316 St & Pacific Hwy S (880 additional trips)
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Figure 34. 2014 Volumes –PM Peak Hour
–Alternative 2
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Figure 35. 2014 Volumes –AM Peak Hour
–Alternative 2
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Figure 36. 2014 Volumes –Saturday Peak
Hour –Alternative 2
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Mitigation
Mitigation for the FWCC project identifies the actions necessary to meet the City’s LOS
threshold for study intersections. The mitigation in this section is divided into PM Peak,
AM Peak, and Saturday peak hours to isolate the impacts of each of these intersection
locations. The specific level of mitigation necessary for any particular future
development project will be determined during the City's project review and based on an
analysis of site access. However, only mitigation measures included in this EIS and
incorporated into the City Council-approved Planned Action Ordinance will be required
to address off-site impacts. The specific dollar amount of any required mitigation
contribution will be on the basis of proportional impacts at rates to be determined by
City Council. All mitigation measures suggested in this report are subject to the review
and approval of City staff and the Federal Way City Council.
Mitigation Cost Assumptions
The following assumptions were used to estimate the costs of mitigation improvements.
For purposes of this analysis, costs were factored using a 3.0% annual growth rate to
estimate 2009 costs.
Table 27. Mitigation Cost Assumptions
Improvement 2009 $
Construction
1. Widening in City Center or on state highways $89/SF
2. Widening in other commercial zones $76/SF
3. Widening elsewhere $63/SF
4. Shoulder widening $13/SF
5. Lighting $66/LF
6. Signal Pole Relocation $69,000/EA
7. Retaining Wall $127/SF
8. New Signal $228,000/EA
9. Mobilization 8.0% of construction
Right of Way
1. Right of way $44/SF
2. Parcel purchase Market Value
3. Parking stalls loss $5,000/EA
Project Development
1. Permitting 5% of construction
2. Contingency 30% of construction
3. Design 25% of construction
4. Construction Eng 15% of construction
5. Stormwater 20% of construction
Costs estimates developed in consultation with the City of Federal Way Department of Public Works. 2004 to 2009
assumed 3% annual growth factor for the cost for construction and materials.
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Mitigation Improvements
Mitigation improvements for this study were based on projects identified by the City
through their capital improvement planning process and other area planning projects.
Sources of mitigation improvements for the intersections include:
2009-2020 Capital Improvement Plan (CIP)
2030 City Center Access Study (2005) – Traffic Systems Management (TSM)
Projects
Other mitigation improvements were based on the results of the LOS analysis. These
improvements include: signal optimization and addition of turn lanes. All mitigation
improvements were identified for feasibility and reviewed by City staff.
In some cases, mitigation actions may not be feasible, reasonable, or desirable. In
these cases, mitigation may require changes in current policies or result in undesired
consequences, such as long vehicle delays or pedestrians access issues. While there
may be actions that could bring an intersection to the City’s LOS threshold, investigation
of these mitigation actions fall outside the scope of this analysis and would require
policy changes by the City or State to implement. Examples of these types of mitigation
include:
The cycle length to extend beyond a 120 second cycle
Relocation or removal of businesses
Triple turn lanes at major intersections
Additional through lanes on a major thoroughfare
Conversion of HOV lanes to be used for general purpose travel on Saturdays
Limits on turning movements at an intersection (no left turn)
Development of parallel travel routes
Changes to physical topography
All mitigation measures suggested in this report are recommended actions, subject to
the review and approval of City staff, and adoption by City Council.
Comparison of Alternatives
The following section provides a comparison of the mitigation needed for the No Action
and Action alternatives. For each study period, mitigation improvements are provided
along with an estimated 2009 cost. Costs indicated reflect costs calculated in the 2009-
2020 Capital Improvement Plan or were estimated based on the project cost
assumptions provided by the City. Estimated costs include right-of-way purchases
necessary to develop the roadway to meet the City of Federal Way Comprehensive
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Planning & Engineering
Plan (2003 revision, Chapter 3) Planned Street Sections (Figure III-3). All costs
represent the cost of construction, right-of-way acquisition, and design and engineering.
The costs do not include environmental mitigation, utility improvements or relocation, or
financing.
The mitigation for Alternatives 1 and 2 represents improvements that are needed, in
addition, to the No Action (Alternative 3) improvements.
PM Peak Hour
For the PM peak hour, improvements would be needed to meet the City’s LOS standard
for the No Action alternative. Optimization of signal timing is assumed to occur as part
of future City signal coordination activities. No further improvements are required during
the PM peak hour for Alternative 1 and 2. Table 28 indicates the PM peak hour
improvements identified for the three alternatives.
Table 28. PM Peak Hour 2009 Mitigation
ID Intersection Improvement 2009 Cost
($ x1000)
PM Alternative 3 – No Action
8 S 312 St & Pacific Hwy S Add 2nd northbound left turn lane (CIP 01-05) $ 2,080a
21 S 336 St & Pacific Hwy S Optimize signal timing 0
Alternative 3 Total $ 2,080
PM Alternative 1 – Additional Mitigationb
8 S 312 St & Pacific Hwy S No Additional Improvements Requiredb 0
21 S 336 St & Pacific Hwy S No Additional Improvements Requiredb 0
Alternative 1 Additional Mitigationb $ 0
PM Alternative 2 – Additional Mitigationb
8 S 312 St & Pacific Hwy S No Additional Improvements Requiredb 0
21 S 336 St & Pacific Hwy S No Additional Improvements Requiredb 0
Alternative 2 Additional Mitigationb $ 0a Estimate provided by the City of Federal Way factored to 2009. b In addition, No Action (Alternative 3) mitigation improvements would be required for this alternative.
The final mitigation improvements for the FWCC would be reviewed and adopted by
City Council. As identified in this study, Alternatives 1 and 2 would require no additional
mitigation over actions needed for the No Action alternative. The No Action mitigation
would be approximately $2.1 million. FWCC development may be required to fund a
proportional share of the No Action Alternative improvements.
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AM Peak Hour
As shown in Table 29, no additional mitigation is required for the AM peak hour,
assuming the completion of the PM peak hour mitigation indicated in Table 28.
Table 29. AM Peak Hour 2009 Mitigation
ID Intersection Improvement 2009 Cost
($x1000)
AM Alternative 3 Mitigation
No mitigation required
Alternative 3 Total $ 0
AM Alternative 1 Additional Mitigation
No mitigation required
Alternative 1 Additional Mitigation $ 0
AM Alternative 2 Additional Mitigation
No mitigation required
Alternative 2 Additional Mitigation $ 0
Saturday Peak Hour
Table 30 lists the Saturday peak hour mitigation improvements. The City’s Guidelines
for the Preparation of Transportation Impact Analyses (June 2004) does not specifically
address mitigation for the Saturday peak hour. The City Council would need to make a
policy decision on whether the Guidelines apply to time periods outside of the PM peak
hour. Assuming mitigation is necessary, the identified improvements for the FWCC
would be reviewed and adopted by City Council. As identified in this study, the
Saturday peak hour analysis assumes the completion of the PM peak hour
improvements indicated above.
Tables 28-30 indicate planning level cost estimates for roadway improvements and
right-of-way acquisition to meet the City of Federal Way’s Planned Street Sections
described in the City of Federal Way Comprehensive Plan (2003 revision, Chapter 3).
In some cases, right-of-way acquisition is minor, with impacts to a small portion of
undeveloped parcels. In others, acquiring the right-of-way may result in a full parcel
takes as the acquisition would adversely impact the existing business. Final
determination of the need for full parcel takes will depend on the benefit of the
improvement, the ability to deviate from the City Planned Street Section, and
consideration of alternatives such as centerline relocation and other planned roadway
improvement projects.
Most of the Saturday mitigation would be required for the No Action alternative. Two
options are provided for construction of the northbound right turn lane at S. 320th Street
and 20th Avenue S intersection. The first option relocates a proposed sidewalk to the
west of a future but permitted building, eliminating the need for a full building take. The
second option purchases the building and constructs the sidewalk within the roadway
right-of-way. The difference between the two options is estimated at $2.6 million. The
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range of costs for the No Action alternative would be approximately $2.5 million to $5.2
million. Alternatives 1 and 2 would require $3.2 million of additional improvements
amounting to a total (including Alternative 3) of approximately $5.7-$8.4 million.
Table 30. Saturday Peak Hour 2009 Mitigation
ID Intersection Improvement 2009 Cost
($x1000)
Saturday Alternative 3 Mitigation
Northbound right turn lane (TSM 2) Option 1 521
Northbound right turn lane (TSM 2) Option 2 3,17014 S 320 St & 20 Av S
Southbound right turn lane 1,029
15 S 320 St & 23 Av S Second northbound right turn lane. (TSM 3) 1,003
Alternative 3 Total $ 2,553-5,202
Saturday Alternative 1 Additional Mitigation*
10 S 316 St & Pacific Hwy S Eastbound right turn lane (TSM 12) $ 717
13 S 320 St & Pacific Hwy S Northbound right turn lane 729
14 S 320 St & 20 Av S No Additional Improvements Required 0
15 S 320 St & 23 Av S Westbound right turn lane 1,737
Alternative 1 Additional Mitigation* $ 3,183
Saturday Alternative 2 Additional Mitigation*
10 S 316 St & Pacific Hwy S Eastbound right turn lane (TSM 12) $ 717
13 S 320 St & Pacific Hwy S Northbound right turn lane 729
14 S 320 St & 20 Av S No Additional Improvements Required 0
15 S 320 St & 23 Av S Westbound right turn lane 1,737
Alternative 2 Additional Mitigation* $ 3,183
*In addition, No Action (Alternative 3) mitigation improvements would be required for this alternative.
Timing of Implementation
Mitigation improvements for the area will depend on the location and rate of
development within the FWCC. In addition, the timing of projects will depend also on
the whether Saturday projects will be mitigated to the PM Peak hour thresholds. PM
peak hour improvements are the highest priority, because Saturday and AM peak hour
analyses assumed the completion of the PM peak hour projects.
All projects identified for the selected FWCC alternative will be needed by 2010 to meet
the City’s transportation threshold for the expected level of development. Table 31
shows the expected intersection operations after completion activities. With the
improvements, intersections within the jurisdiction of the City of Federal Way will meet
the LOS E and less than 1.0 volume-to-capacity threshold.
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Table 31. Intersection Operations by Peak Hour with Mitigation
PM PEAK Alternative 3 Alternative 1 Alternative 2
Mitigated Mitigated Mitigated
ID Intersection LOS v/c LOS v/c LOS v/c
1 S 272 St & Pacific Hwy S F 1.101,3 F 1.091,3 F 1.091,3
2 S 272 St & I-5 southbound Ramp F 1.021,3 F 1.001,3 F 1.001,3
4 S 272 St & Military Rd S F 1.241,3 F 1.221,3 F 1.221,3
8 S 312 St & Pacific Hwy S D 0.95 D 0.95 D 0.95
21 S 336 St & Pacific Hwy S D 0.92 D 0.93 D 0.93
AM PEAK Alternative 3 Alternative 1 Alternative 2
Mitigated Mitigated Mitigated
ID Intersection LOS v/c LOS v/c LOS v/c
3 S. 272 St & I-5 northbound Ramp (WSDOT) E 1.081,3 E 1.091,3 E 1.091,3
4 S. 272 St & Military Rd S (City of Kent) F 1.091,3 F 1.101,3 F 1.101,3
SATURDAY PEAK Alternative 3 Alternative 1 Alternative 2
Mitigated Mitigated Mitigated
ID Intersection LOS v/c LOS v/c LOS v/c
10 S 316 St & Pacific Hwy S --2 --2 D 0.92 C 0.92
13 S 320 St & Pacific Hwy S --2 --2 E 0.96 E 0.941
14 S 320 St & 20 Av S D 0.95 D 0.99 D 0.99
15 S 320 St & 23 Av S E 0.921 E 0.92 E 0.93
1. Results from HCM2000 Signals (version 4.1f)
2. Meets City’s threshold without mitigation
3. Does not trigger other jurisdictions threshold for mitigation
Additional Mitigation
The mitigation identified in this analysis is focused on the roadway improvements
necessary to meet the expected travel demand on area roadways associated with the
proposed development in the project area. Development will also need to meet the
requirements of applicable codes at the time of application. Such requirements might
include the dedication of right-of-way, installing curbs gutters and sidewalks, drainage
improvements, and other requirements of the City. Additional mitigation may be
required for individual development applications within the project area in order to
reduce area traffic impacts or improve on-site circulation and to meet City and State
requirements for Commute Trip Reduction and Transportation Demand Management.
Actions to be considered include:
On-site improvements – Driveway and circulation actions to minimize impact on area
roadways. Actions may include management of access points, traffic control measures,
construction of internal roadways, pedestrian and bicycle improvements, and
connections to adjacent developments.
Non Motorized mode improvements – Mitigation may be required per site specific
and land use development proposals to address pedestrian, bicycle, and transit
improvements to support the plans, policies, and goals as noted within the City of
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Federal Way Comprehensive Plan City Center Element (2002, Chapter 7) and
Transportation Element (2003, Chapter 3).
Grid Roadway Development – Part of the City Center Plan is to develop a number of
internal roadways (see Figure 11 in Appendix 2) to create smaller blocks that will
improve the grid network and improve the access for pedestrians and vehicles. Right-
of-way dedication and street improvements shall be a component of the development
submittal phase of a proposed project within the project area. Roadways within the
project area must meet specific “City Center” design standards as specified in the
Transportation Element (Chapter 3) of the City of Federal Way Comprehensive Plan
(2003 revision, Figure III-3)
Right-of-way Dedication – Right-of-way dedication and frontage improvements may
be required in conjunction with proposed developments. Roadways within the project
area must meet specific “City Center” design standards as specified in the
Transportation Element (Chapter 3) of the City of Federal Way Comprehensive Plan
(2003 revision, Figure III-3).
Transportation Demand Management (TDM) – TDM actions can be used to reduce
the impact of the project and as a mitigation action. These actions may include
provision of transit passes to tenants and employees, ridesharing programs, priority
carpool parking, and guaranteed ride home programs. TDM actions are designed to
primarily address commute trips and may not be applicable as mitigation for all
developments.
Table III-13 (page 60) of the City of Federal Way Comprehensive Plan (2003 revision,
Chapter 3, Transportation Element) stratifies various TDM alternatives by their
functional grouping and potential effectiveness, implementation difficulties, and
expected cost effectiveness. These strategies include: Telecommuting, Parking Pricing
and Subsidy Removal, Compressed Work Week, Employer-Based Management, and
Parking Supply Strategies.
Based upon the above, the following are a list of recommended mitigation measures
that can be considered in conjunction with individual development projects within the
project area:
1. Encourage voluntary expansion of the CTR Program to employers of less than
100 employees. The encouragement by employers may be as diverse as
subsidized bus passes, car pool space priority, bike racks, shower facilities, van
pools, car pool information access, telecommuting, variable work hours, etc.
2. Encourage the formation and expansion of area-wide ride-sharing programs.
Such programs operate with little direct cost to the City and are highly cost-
effective.
3. Support the enhancement of Park and Ride facilities and transit centers to
supplement the regional system, either directly through physical development or
enhancements or indirectly through development conditions where employer
vans are required to shuttle employees to Park and Ride facilities or transit
centers.
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4. Facilitate enhancements to the HOV system. This may include the dedication of
property for HOV lanes, construction of arterial HOV lanes within existing City
ROW, and priority treatments for buses at traffic signals. At the very least, where
feasible, opportunities to enhance access to the State system of HOV lanes
should be considered.
5. Achieve increased densities and mix of uses to support public transportation,
decrease trip generation and parking impacts.
6. Encourage facilities (shelters, loading spaces, etc) to accommodate City Center
shuttle service in association with development projects, together with enhanced
pedestrian and bicycle access and security.
7. Improve pedestrian and bicycle access to bus routes and transit centers. This
can be a requirement of subdivision, development, and redevelopment. The City
may need to acquire easements and construct trail connections. Development
incentives could be granted for providing such amenities that are pedestrian,
bike, and transit friendly. While bicycle, pedestrian, and bus transit services and
facilities may be desirable for other reasons; they should not be looked on as
highly cost-effective strategies to the exclusion of those actions listed above.
Neighborhood Traffic Control – Development within the project area may be required
to include actions to reduce the impact of cut through traffic on residential areas.
Examples of neighborhood traffic control actions include: turn restrictions, speed
controls, traffic enforcement, and parking restrictions.
The following mitigation recommended shall support the following City of Federal Way
Comprehensive Plan (2003 revision) Transportation Element (Chapter 3):
Minimize through traffic on residential streets by maximizing through travel opportunities
on arterial and collector streets.
Employ traffic calming measures in neighborhoods (where feasible) where traffic
volumes and speeds on local streets consistently exceed reasonable levels.
Improve safety on residential streets by:
a. Reducing street widths while maintaining on-street parking.
b. Increasing separation between sidewalks and streets.
c. Reducing design speeds to discourage speeding.
d. Limiting the length of straight streets to discourage speeding.
e. Discouraging the use of four-legged intersections.
Keep through traffic to state routes and arterials. Discourage the use of local or
neighborhood streets for through movements (unless part of an overall process of
creating a street grid).
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Parking – Mitigation actions that reduce the parking requirements within the project
area should be encouraged. Examples include shared parking, employee parking
programs, parking time restrictions, paid parking programs. Shared parking strategies
focus on looking at opportunities where adjacent uses have parking demand profiles
that can support the sharing of a smaller amount of parking spaces. For example, an
office building with an 8 AM to 5 PM demand could share its parking with evening
dominated uses such as restaurants, or a cinema. A parking demand study, which
shows the hourly parking demand profiles for adjacent uses and the potential for joint
parking opportunities within a mixed-use development, can be used to reduce the
number of parking spaces.
In addition, contained in the above TDM mitigation are strategies that overlap with
parking mitigation plans for development. A development may propose a plan and
management system to the City for approval upon submittal of the development permit.
Those items may contain the following in support of the City of Federal Way and state
Commute Trip Reduction (CTR) requirements:
ALTERNATIVE MODE SUPPORT MEASURES
Public education and promotion may increase the effectiveness of these other
strategies up to 3%.
Area-wide Ride matching Services – May result in a 0.1-3.6% reduction in vehicle
miles traveled (VMT) and an up to 2.5% VMT reduction in transit services. Reductions
in parking required may be calculated on the basis of these lower trip-generation rates.
Vanpool Service – May result in an up to 8.3% in commute VMT, as well as a
reduction in transit and vanpool fares up to 2.5%. Reductions in parking required may
be calculated on the basis of these lower trip-generation rates.
Non-Motorized Modes plan and implementation – May result in an up to 0-2%
regional VMT reduction. Reductions in parking required may be calculated on the basis
of these lower trip-generation rates.
HOV Facilities – May result in an up to 1.5% VMT reduction and 0.2% vehicle trip
reduction. Reductions in parking required may be calculated on the basis of these lower
trip-generation rates.
On site development of Park and Ride program – May result in up to 0-0.5% VMT
reduction. Reductions in parking required may be calculated on the basis of these
lower trip-generation rates.
EMPLOYER-BASED TDM MEASURES
Parking mitigation -- Monetary incentives may result in an up to 8-18% trip reduction
at site. Reductions in parking required may be calculated on the basis of these lower
trip-generation rates.
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Alternative Work Schedules – May result in as much as a 1% regional VMT reduction.
Reductions in parking required may be calculated on the basis of these lower trip-
generation rates.
Commute Support Programs – May result in up to 0.1-2.0% regional VMT reduction.
Reductions in parking required may be calculated on the basis of these lower trip-
generation rates.
Parking Management – May result in up to a 20 to 30% reduction in SOV trips to/from
the site. Reductions in parking required may be calculated on the basis of these lower
trip-generation rates.
Telecommuting – Up to 10% commute VMT reduction. Reductions in parking required
may be calculated on the basis of these lower trip-generation rates.
OTHER STRATEGIES
Parking Tax – May result in up to a 1 to 5% reduction in regional VMT and trip
generation, but requires City Council and/or legislative action. Reductions in parking
required may be calculated on the basis of these lower trip-generation rates.
Development Parking Impact Mitigation – Requires Council approval to allow for
payment of parking-mitigation funds towards long term investments in structured
parking solutions in lieu of full parking requirement. Reductions in parking required may
be calculated on the basis of these lower trip-generation rates.
Mixed Land Use/Jobs Housing Balance – May result in VMT reductions up to 10%.
Parking stall credit is given based on overlapping shared usage of mixed facility, per
City Code provisions.
Transit-Oriented and Pedestrian-Friendly Design – Site and building design that
encourages transit usage and/or walking may reduce overall parking requirement.
Requires design review and staff approval.
Employment Center Density - Achievement of sufficient density within the City Center
to constitute a regional employment center may reduce SOV work trips to individual
development projects by up to 50%. Parking stall reductions may also apply to
developments.
Other Parking Management Plans – May mitigate 1 to 5% region-wide VMT, provided
enforcement issues are addressed in the mitigation plan.