20-104351_Trip Gen - Scoping Request Memo-11-6-2020 v1 TENW
Transportation Engineering NorthWest
Transportation Planning | Design | Traffic Impact & Operations
PO Box 65254, Seattle, WA 98155 | Office (206) 361-7333
MEMORANDUM
DATE: November 5, 2020
TO: Soma Chattopadhyay, Traffic Review Engineer
City of Federal Way
FROM: Michael Read, PE, Principal
TENW
SUBJECT: Trip Generation for Redondo Heights TOD
TENW Project No. 2020-199
This memorandum summarizes a preliminary trip generation analysis for the proposed Redondo Heights
TOD project by Shelter Resources, which is being provided with the Transportation Concurrency
Application. This memo includes a project description, methodology used to derive the trip generation
estimate, a trip generation summary, and request for further traffic scoping information by the City of Federal
Way. Although likely to be processed under separate permits, this analysis and required Transportation
Impact Analysis will address the cumulative impacts of both projects.
Project Description
The proposed development is located on the east side of SR 99 (Pacific Highway S) in Federal Way. The
proposed project is a development of vacant property surrounding the existing Silver Shadow Apartment
complex. At completion, the proposed project would include up to 202 residential apartment units and a
11,000 square feet (SF) of commercial building area currently assumed as a daycare facility for traffic
analysis/concurrency review purposes. Preliminary site plan concepts are provided in Attachment 1.
Vehicle access to/from the site would continue at the existing access driveway to the Silver Shadow
Apartments with a secondary fire/emergency vehicle only driveway onto S 276th Street that serves the
adjacent Redondo Heights Park-And-Ride. The frontage portion of the site would also be accessible via a
new driveway onto SR 99 for access to commercial surface parking and garage parking for residential
uses. In total, the site would have three public access driveways, two open onto SR 99 and an EVA-only
onto S 276th Street. In total, approximately 394 parking stalls would be provided on-site in both garage
and structured spaces.
Trip Generation Methodology
The weekday daily, AM peak hour, and PM peak hour trip generation estimates for the proposed Redondo
Heights TOD development were based on trip rates published in the Institute of Transportation Engineers
(ITE) Trip Generation Manual, 10th Edition, 2017. ITE Land Use Code (LUC) 221 was used for the 202
mid-rise apartment units and LUC 565 for the 11,000 SF of daycare facility.
Given the site would be adjacent to the Redondo Heights Park-And-Ride and high frequency transit service it
provides as well as within walking distance of the future S 272nd Street Link light rail station, for this
preliminary analysis a mode share adjustment was applied consistent with previous Sound Transit
Trip Generation for Redondo Heights TOD
TENW November 5, 2020
Page 2
adjustments for walk access to the residential uses. No adjustments were applied to the proposed
commercial uses.
Trip Generation Summary
Based on the detailed trip generation methodology described in the previous section, Table 1 summarizes
the weekday trip generation. As shown in Table 1, the project is estimated to generate a net increase of
approximately 1,458 daily vehicular trips, with 183 trips occurring during the AM peak hour and 198 trips
in the PM peak hour. Detailed trip generation calculations are provided in Attachment 2.
Table 1
Redondo Heights TOD – Trip Generation Summary
Time Period In Out Total
Weekday Daily 1,173 1,173 1,458
Weekday AM Peak Hour 91 92 183
Weekday PM Peak Hour 105 93 198
Based upon the cumulative trip generation, a full Transportation Impact Analysis per City of Federal Way
will be required. Please advise on specific study intersections beyond those serving the immediate
vicinity/site access including:
Pacific Highway S (SR 99) and S 272nd Street
Pacific Highway S (SR 99) and S 276th Street
Pacific Highway S (SR 99) and Site Access Driveway(s)
Pacific Highway S (SR 99) and 16th Avenue S
Pacific Highway S (SR 99) and S 288th Street
If you have any questions regarding the information presented in this memo, please call me at (206) 361-
7333 x 101 or mikeread@tenw.com. We look forward to any traffic study scoping comments the City
may require.
cc: Len Brannen, President, Shelter Resources, Inc.
Mark D Simpson, AIA, Principal, Bumgardner
Attachments: 1. Site Plan Concepts
2. Trip Generation Calculations
ATTACHMENTS
Site Plan
(Front Parcels and Back Parcels)
VISITOR PARKING
VISITOR PARKING
VAN
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
VISITOR PARKING
VISITOR PARKING
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
VISITOR PARKING
VISITOR PARKING
1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
VANVISITOR PARKINGVISITOR PARKING1601 5th Avenue, Suite 1600
Seattle, WA 98101
206.622.5822
www.kpff.com
Trip Generation Calculations
ITE Trip Generation, 10th EditionRedondo Heights TOD, Federal Way, WALU DailyProposedX Code Enter Exit Trips Enter Exit Trips Trips Daily Rate AM Rate PM RateMultifamily Housing (Mid-Rise)202 221 19 54 73 54 35 89 1099 5.44 0.36 0.44Daycare Center11.0 565 75 46 121 59 63 122 524 47.62 11.00 11.12-3 -8 -11 -8 -5 -13 -165Net Project Trip Generation91 92 183 105 93 198 1458Source: Sound Transit Access Mode Analysis of Northgate Station Access Study.A walk mode share of 25% of an assumed 60% home‐based work trips was applied to account for adjacent transit center/LRT station.AM Peak PM PeakTransit/LRT Station Area Reduction(25% of Home-Based Work Trips)Redondo Heights TOD ‐ TGEN AM‐PM.xls