2017-07-12 GTC Traffic Impact Analysis.pdf
2813 Rockefeller Avenue Suite B Everett, WA 98201
Tel: 425-339-8266 Fax: 425-258-2922 E-mail: info@gibsontraffic.com
MEMORANDUM
To: Farrell Fleming, Edmonds Senior Center
From: Matthew Palmer, PE
Project: Edmonds Waterfront Center, GTC #17-138
City of Edmonds Trip Generation and Mitigation
Date: July 12, 2017
This memorandum summarizes the trip generation and mitigation analysis for the proposed
development which will consist of 25,000 Square Feet (SF) of Senior Center building/classroom
space. The site is located at 220 Railroad Avenue in the City of Edmonds. The site location is
shown in Figure 1 in the attachments. The site currently consists of 22,000 SF of Senior/Community
Center (per Information provided by the Edmonds Senior Center). The south access will remain an
exit only and the access will shift to the south property line. The north access will switch from a
full access today to become an inbound only access.
Trip Generation
The PM peak-hour trip generation for the existing Senior/Community Center was determined based
on counts conducted by Traffic Data Gathering. Two days (Wednesday June 14th and Thursday
June 15th) of PM peak-hour counts were conducted from 4 to 6 PM to figure out what the PM peak-
hour trip generation for the existing site is. The counts show there were 12 trips from 4:45 to 5:45
PM on Wednesday and 9 trips from 4 to 5 PM on Thursday. The existing average trip generation
rate during the PM peak-hour based on 22,000 SF is 0.48 PM peak-hour trips/1,000 SF. With the
inbound percentage as 43% and an outbound percentage of 57%.
Using this rate for the new square footage (25,000 SF) the new building would have an anticipated
trip generation of 11.93 PM peak-hour trips (5.14 Inbound/6.79 Outbound). This results in 1.43 net
new PM peak-hour trips when the existing building is credited towards the new buildings trip
generation. It’s anticipated that the ADT for the new building would be 10 times the PM peak-hour
trips; therefore, 14.30 new ADT would be anticipated with the expansion.
Mitigation Fees
The applicable traffic mitigation fees are from City of Edmonds Code Section 3.36.125. The 2017
Impact Fee Rate for the new building is $2,543.01 per trip; while credit for the removed 22,000 SF
is based on the 2004 Impact Fee Rate of $763.66 as the previous use was permitted before
9/12/2004. There is no land use for the senior/community center; therefore, a trip length factor of
1.00 and 100% new trips were utilized to be representative of the destination. The traffic mitigation
fee calculation for the Edmonds Waterfront Center is summarized in Table 1.
Edmonds Waterfront Center Trip Generation & Mitigation Memo
Gibson Traffic Consultants, Inc. July 2017
info@gibsontraffic.com 2 GTC #17-138
Table 1: Traffic Mitigation Fee Calculation
Access Analysis
The site will have two accesses; the south access will remain an exit only and the north access will
switch from a full access today to become an inbound only access. Both accesses are to Railroad
Avenue, which is a straight and consistent grade roadway that doesn’t pose any stopping sight
distance obstructions. Based on the trip generation it’s anticipated there will be less than 10 new PM
peak-hour trips at any of the City intersections.
Summary/Conclusions
The redevelopment of the site would generate 1.43 new PM peak hour trips. The site has two
access points and would not be anticipated to impact any critical intersection with 10 new PM peak-
hour trips; therefore, off-site mitigation should not be required. With the credit for the previously
permitted use the traffic mitigation fee would be $22,319.68.
Attachments (A-1 to A-3)
Land Use Square
Feet
PM
Trips
Cost per
Trip Total
Senior Center 25,000 SF 11.93 $2,543.01 $30,338.11
Senior Center -22,000 SF 10.50 $763.66 -$8,018.43
Total 3,000 SF 1.43 --- $22,319.68
MAIN ST
3RD AVE N
SUNSET AVE N
DAYTON ST
5TH AVE NJAMES ST
BELL ST
EDMONDS ST
DALEY ST
BELL STMAIN ST
FERRY DOCK
2ND AVE N
SITE
R AIL R O A D A V E
LEGEND
SITE VICINITY MAP
PROJECT SITE
FIGURE 1
TRAFFIC IMPACT STUDY
CITY OF EDMONDS
G IBSON T RAFFIC C ONSULTANTS
EDMONDS WATERFRONT
CENTER
(25,000 SF)
GTC #17-138
N
Date : Wednesday 6/14/2017 from 4:00 to 6:00 PM
IN OUT Hourly In Out
4:46 PM 1 4:00-5:00 4
4:54 PM 1 4:15-5:15 9
4:56 PM 1 4:30-5:30 11
4:58 PM 1 4:45-5:45 12 5 7
5:00 PM 1 5:00-6:00 8
5:01 PM 1 42% 58%
5:04 PM 1 2
5:19 PM 1
5:20 PM 1
5:38 PM 1
Date : Thursday 6/15/2017 from 4:00 to 6:00 PM
IN OUT Hourly In Out
4:08 PM 1 4:00-5:00 9 4 5
4:11 PM 1 4:15-5:15 7
4:15 PM 1 4:30-5:30 4
4:16 PM 1 4:45-5:45 4
4:20 PM 1 5:00-6:00 2
4:25 PM 1 44% 56%
4:35 PM 1
4:54 PM 1
4:57 PM 1
5:29 PM 1
5:30 PM 1
In Out
43% 57%
10.50 2-day Avg 4.52 5.98
Existing Square Footage 22,000 0.48 /1,000 SF
New Square Footage 25,000 11.93 trips total 5.14 6.79
1.43 net new trips 0.62 0.82
PM Peak-Hour Trips
Edmonds Senior Center
In/Out of Senior Center - Vehicle Trips
Time
220 Railroad Ave, Edmonds
Time
220 Railroad Ave, Edmonds