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Transportation Technical Report
Addendum to SEPA Checklist HEMNSWIS •
2. BACKGROUND CONDITIONS
This section discusses the existing and future conditions without the proposed project. These are the
base conditions against which the impacts of the proposed project are evaluated. Year 2025 is the
long range planning year defined by the City Comprehensive Plan, in which the proposed change in
land use designation would be adopted. Therefore, 2025 was also selected as the future horizon year
for all analyses.
2.1. Roadway Network
The following roadways serve the site:
Edmonds Way (SR 104) is a principal arterial located along the east side of the site. It is oriented
north -south adjacent to the site, but curves to a northwest -southeast orientation south of the site.
Adjacent to the site, it has two southbound general purpose lanes, and three northbound lanes the
two rightmost northbound lanes serve as ferry traffic queuing lanes, and lead to the Edmonds Ferry
Terminal entrance just north of Dayton Street. A substantial amount of the northbound and
southbound traffic along this segment of SR 104 is generated by the ferry terminal. No on -street
parking is allowed. The speed limit adjacent to the site is 40 miles per hour (mph); there are curbs,
gutters, and sidewalks along both sides of the roadway. North of Dayton Street, SR 104 is named
Sunset Avenue S. The sidewalk located on its west side provides a direct pedestrian connection from
the site to Edmonds Station and the ferry terminal.
Dayton Street is an east -west collector located along the north side of the site. It has one travel lane
in each direction. West of SR 104, it has a center lane that transitions into left turn lanes at all
intersections. It has curbs, gutters, and sidewalks on both sides of the street. No on -street parking is
allowed adjacent to the site. It has a speed limit of 25 mph. Although it does not have any dedicated
bicycle facilities, the road has been designated by the City as a bicycle route.'
2.2. Traffic Volumes
Existing PM peak hour traffic volumes were determined from a count conducted by All Traffic Data
Services, Inc. at the Edmonds Way/Dayton Street intersection on Thursday, February 9, 2012. Existing
site -generated traffic was estimated using rates published in the Institute of Transportation Engineers'
(ITE) Trip Generation? These rates were applied to the existing land uses on the site and the resulting
driveway trip estimates were balanced with the counts at the Edmonds Way/Dayton Street intersection.
(Trip generation methods are described in detail in Section 3.2 Trip Generation.) The existing PM peak
hour volumes are shown on Figure 2. Note, although two driveways currently exist on Dayton Street,
driveway volumes were consolidated to one location to reflect a worst-case condition.
To estimate 2025 background (without project) traffic conditions, an average annual growth rate of
1.2% was applied to existing volumes. The average growth rate was derived by comparing existing
and 2025 traffic volumes from the Comprehensive Transportation Plana for the city analysis
intersection nearest the site, and also the nearest analysis intersection on Edmonds Way. The projected
2025 without -project PM peak hour volumes are shown on Figure 3.
City of Edmonds, Comprehensive Transportation Plan, November 2009.
a ITE, 8`h Edition, 2008.
s City of Edmonds, Comprehensive Transportation Plan, November 2009.
- 3 - May 21, 2012
N
Not to Scale
LEGEND
Traffic Signal
Stop Sign
,*---XX PM Peak Hour Volume
Port of Edmonds
Figure 2
EXISTING (2012) TRAFFIC VOLUMES
PM PEAK HOUR
N
Not to Scale
AXOT401HO
Traffic Signal
Stop Sign
4 --XX PM Peak Hour Volume
I
sort of Edmonds
Figure 3
FUTURE (2025) WITHOUT PROJECT
TRAFFIC VOLUMES - PM PEAK HOUR
Harbor Square Redevelopment
Transportation Technical Report
Addendum to SEPA Checklist
2.3. Level of Service
heffron
trans Vrtatian, inc.iii
Level of service (LOS) analysis was performed to document PM peak hour traffic operations in the
study area. The PM peak hour is the focus of this analysis because it is typically the most congested
hour of the day. Level of service is a qualitative measure used to characterize traffic operating
conditions of roadways and intersection. Six letter designations, "A" through "F," are used to define
level of service. LOS A is the best and represents good traffic operations with little or no delay to
motorists. LOS F is the worst and indicates poor traffic operations with long delays. Appendix A
presents the level of service criteria for signalized and unsignalized intersections.
Levels of service were calculated using methodologies based on those presented in the Highway
Capacity Manual (HCM) 4 All level of service calculations were performed using Trafficware's
Synchro 8.0 analysis software. The analysis results are reported from the Synchro calculation module,
which refines the HCM methods to account for more detailed driving behavior. Results for
unsignalized intersections were reported using the HCM Unsignalized module. Intersection geometry,
traffic signal timing, and signal phasing for this analysis were verified through field observation.
Table 2 summarizes the level of service results for existing (2012) and future 2025 -without -project
conditions. The table shows that all three study -area intersections currently operate at LOS A or B,
and are projected to continue operating at those levels through year 2025 without the project.
Table 2. PM Peak Hour Level of Service - Existing and 2025 -Without -Project Conditions
Intersection
LOS i
Existing
Delay 2
2025 Without Project
LOS Dela
Signalized Intersection
Edmonds Way (SR 104) / Dayton Street
A
8.2
A
8.7
Unsignalized Intersections
Dayton Street / North Site Driveway (overall) 3
A
5.1
A
4.7
Northbound left- and right- tums from driveway
B
11.6
B
12.1
Westbound left-tums into driveway
A
8.3
A
8.4
Edmonds Way (SR 104) / East Site Driveway (overall) 4
A
0.9
A
0.8
Eastbound right -turns from driveway
B
12.1
B
12.9
Source: Heffron Transportation, Inc., February 2012,
1. Level of service.
2. Average seconds of delay per vehicle.
3. Two driveways currently exist on the site at Dayton Street, driveway volumes were consolidated to one location to reflect a worst-
case condition.
4. This driveway intersection is physically restricted to right -turn in and right -turn -out movements only, it is expected that any driveway
provided at SR 104 under future conditions would maintain this configuration.
4 Transportation Research Board, 2010.
- 6 - May 21, 2012
Harbor Square Redevelopment
Transportation Technical Report
Addendum to SEPA Checklist
2.4. Parking
Parking in the vicinity of the site is accommodated by on-site surface parking lots. The existing
Harbor Square parking lot includes approximately 425 parking spaces.
2.5. Transit
The site area is served by bus and rail public transit services, which are accessed from Edmonds
Station, located one block north of the site, and by ferry, which is accessed two blocks north of the
site. Bus service is provided by Community Transit, with Routes 110 (Lynnwood), 116 (Lynnwood,
Mill Creek), 131 (Shoreline, Lynnwood), and 416 (Downtown Seattle) serving the site vicinity.
Sounder commuter rail service, provided by Sound Transit, operates between Seattle and Everett with
stops in Edmonds and Mukilteo. Edmonds also serves as a stop along the Seattle—Vancouver Amtrak
Cascades route, with two northbound trains and two southbound trains stopping in Edmonds each
day. The Amtrak Empire Builder provides cross-country service between Seattle and Chicago, with
one eastbound train departing from Edmonds each evening and one westbound train arriving in
Edmonds each morning.
Washington State Ferries operates the Edmonds -Kingston route, which connects the northern portion
of the Kitsap Peninsula and the Olympic Peninsula with northern King and southern Snohomish
Counties. There are 26 daily departures from the Edmonds Ferry Terminal on weekdays and 23 daily
departures on weekend days.
2.6. Non -Motorized Transportation Facilities
As described previously in Section 2.1 Roadway Network, all roads in the site vicinity have sidewalks
on both sides. The sidewalk located on the west side of Edmonds Way provides a direct pedestrian
connection to Edmonds Station and the ferry terminal from the site. Dayton Street does not include
any dedicated bicycle facilities, but has been designated by the City as a bicycle route.
- 7 - May 21, 2012
Harbor Square Redevelopment e f f r on
Transportation Technical Report
Addendum to SEPA Checklist . . . .
This section describes the conditions that would exist with the proposed redevelopment constructed
and occupied. As described previously, the proposed action is the adoption of amendments to the Port
Master Plan and City Comprehensive Plan for a conceptual redevelopment plan for the site. The
amendments consist of land use designation changes that would allow for future redevelopment of the
project site. Analysis presented in this report reflects the land use changes that are anticipated to occur
if the amendments are adopted. First, the increase in automobile trips generated by the proposed
redevelopment was estimated. Then, these trips were added to the 2025 -without -project traffic
volumes. Finally, level of service analysis was performed to determine the potential impact of the
redevelopment on traffic operations in the study area. Potential impacts to the City's concurrency
intersections and other components of the transportation network were also evaluated. The following
sections describe the methodology used to determine the proposed project's impacts.
3.1. Roadway Network
The proposed land use designation change is a non -project action and does not include details about
proposed access to public streets. It is expected that internal access roads will be proposed as part of
project -specific details and will be analyzed at the project level prior to permitting. As described
previously, the analysis presented in this report assumes one site driveway located at each adjacent
street, which represents a worst-case scenario for traffic operations. It is possible that additional
driveways would be proposed when project -level details are developed. No modifications to the off-
site road network are expected to occur as part of the proposed redevelopment.
3.2. Trip Generation
The potential redevelopment would include two actions that would influence traffic near the site:
1. Removal of the existing industrial, retail and office uses, and
2. Construction of the proposed new transit -oriented development that would include a mix of
retail, office, and residential uses.
Traffic analysis was performed using the net change in site -generated trips, which is the difference
between the trips generated by the existing and the proposed uses. The following describes the
assumptions used to determine the change in traffic anticipated from the proposed project.
3.2.1. Trip Rates
Trip generation for the proposed redevelopment was estimated using rates published by ITE, which
compiles trip generation counts throughout the country for a variety of land -use types. Trip generation
rates and equations from Trip Generations were applied based on the types of uses proposed for this
site. Table 3 summarizes the trip generation rates used for this analysis.
s Institute of Transportation Engineers (ITE), 8`h Edition, 2008.
-8- May 21, 2012
Harbor Square Redevelopment
Transportation Technical Report
Addendum to SEPA Checklist
Table 3. Trip Generation Rates
heffron
trans`p ortation,
ITE Land
ITE
Trip Generation Rates
Use Code
Land Use
Daily
AM Peak
PM Peak
110
Light Industrial
6.97 trips/1,000 sf
0.92 trips/1,000 sf
0.97 trips/1,000 sf
50% in
88% in
12% in
50% out
12% out
88% out
150
Warehouse
3.56 trips/1,000 sf
0.30 trips/1,000 sf
0.32 trips/1,000 sf
50% in
79% in
25% in
50% out
21% out
785% out
220
Multi -Family Residential
6.65 trips/unit
0.51 trips/unit
0.62 trips/unit
50% in
20% in
65% in
50% out
80% out
35% out
310
Hotel
8.17 trips/room
0.56 trips/room
0.59 trips/room
50% in
61% in
53% in
50% out
39% out
47% out
492
Health Club
32.93 trips/1,000 sf
1.38 trips/1,000 sf
3.53 trips/1,000 sf
50% in
45% in
57% in
50% out
55% out
43% out
710
General Office
11.01 trips/1,000 sf
1.55 trips/1,000 sf
1.49 trips/1,000 sf
50% in
88% in
17% in
50% out
12% out
83% out
820
Retail (Shopping Center)
42.94 trips/1,000 sf
1.00 trips/1,000 sf
3.73 trips/1,000 sf
50% in
61% in
48% in
50% out
39% out
52% out
Source: Institute of Transportation Engineers, P Edition, 2008.
3.2.2. Internal Trips
The total number of trips generated by a site also reflects "internal trips," or trips made between one
use on the site and another use on the site. Chapter 7 of the Trip Generation Handbook6 is devoted to
estimating trip generation for multi -use developments, and provides a methodology to estimate the
number of internal trips that can be expected at specific types of sites. This method is based on the
type and size of various land uses. The more balanced the mix of uses, the higher the percentage of
internal trips. Developments with a predominance of one type of use (e.g., mostly office, or mostly
residential) typically have lower percentages of internal trips.
ITE's methodology to determine internal trips has four steps:
1. Determine the number of trips expected to be generated by each land use as if each was
on a separate site.
2. Determine the number of internal trips based on internal capture rates presented in the
Trip Generation Handbook.
6 Institute of Transportation Engineers, June 2004.
-9- May 21, 2012
Harbor Square Redevelopment
Transportation Technical Report
Addendum to SEPA Checklist
3. Balance the number of internal trips to and from all land uses at the site.
4. Total the resulting number of internal trips and calculate the percentage of internal trips.
The Trip Generation Handbook provides internal trip capture percentages for retail and residential
uses for daily and PM peak hour conditions. However, the handbook does not provide percentages for
the AM peak hour. Therefore, AM peak hour percentages were derived using data from Internal Trip
Capture Estimator for Mixed -Use Developments. This publication includes tables of "unconstrained"
internal capture percentages for interaction between several land uses including retail and residential.
The trip generation analysis assumes a worst-case condition that retail uses are open and generating
trips during the AM peak hour, in which case internal trips would occur. If the retail shops are closed
before 9:00 A.M., the project would generate fewer trips than assumed.
The analysis determined that with the proposed redevelopment, 7% of daily trips, 6% of AM peak
hour trips, and 7% of PM peak hour trips would be internal to the site. Because existing land use on
the site also includes a mix of office and retail uses, internal trips were also estimated for existing
conditions. For existing development on the site, the analysis indicated that 5% of daily trips and 3%
of PM peak hour trips would be internal. For both existing and proposed trip generation, internal trips
would remain on site and were therefore subtracted from the total trip generation.
3.2.3. Mode of Travel
External trips would occur in automobiles, on bicycles, on transit, and on foot. The mode -of -travel
estimates were determined for the proposed office and residential uses based on `Journey -to -Work'
survey results from the 2000 Census provided by the PSRC. From these surveys, transit and non -
automobile (walk, bicycle, and work -from -home) mode -of -travel percentages for residents and
employees within Transportation Analysis Zone JAZ) 578—the zone including and surrounding the
project site—were used. Based on the PSRC data, 4% of office trips were assumed to be transit or
walk, and 96% to be vehicle trips. For residential, 10% of trips were assumed to occur via transit or
on foot, and the remaining 90% were assumed as vehicle trips. For retail trips, 10% were assumed to
occur by transit or on foot, and the remaining 90% were assumed as vehicle trips (based on
experience in other similar locations with street -level retail development). Hotel and industrial uses
were assumed to generate 100% vehicle trips. These mode split assumptions were applied to both
existing and proposed trip generation estimates. It should be noted that for the proposed
redevelopment, application of historical mode percentages is very conservative since the project is
expected to be designed as transit oriented development, which should result in higher use of transit
and non -vehicle modes.
3.2.4. Vehicle Trips
Table 4 summarizes the projected vehicle trip generation for the proposed redevelopment, including the
reductions for internal and non -vehicle trips. When implemented at the project level, full build -out of
the proposed land use is estimated to generate up to 8,030 total vehicle trips per day, with about 405
trips occurring in the AM peak hour (typically one hour between 6 and 8 A.M.) and 770 trips occurring
in the PM peak hour (typically one hour between 4 and 6 P.M.). Trips associated with existing uses on
the site would be removed from the roadway network. After accounting for the removal of the existing
site uses and their associated traffic, the planned uses are projected to generate up to 3,310 net new
Texas Transportation Institute, December 2007; Published: February 2010.
_10- May 21, 2012
Harbor Square Redevelopment
Transportation Technical Report
Addendum to SEPA Checklist
trips per day, with about 100 net new trips occurring in the AM peak hour and 270 net new trips
occurring in the PM peak hour.
Table 4. Trip Generation Summary
Source: Heffron Transportation, Inc., February 2012.
3.3. Trip Distribution and Assignment
The PM peak hour trip distribution pattern for this project was derived from trip origin and destination
data obtained from the City of Edmonds travel demand forecasting model. Figure 4 shows the projected
distribution of net new project trips throughout the study area, based on the model data. The forecasted
net changes in project -generated traffic were added the 2025 -without -project traffic volumes to estimate
with -project traffic volumes. These projected volumes are shown on Figure 5.
- 11 - May 21, 2012
AM Peak Hour Trips
PM Peak Hour Trips
In
Out
Total
In
Out
Total
Land Use Size
Daily Tris
Proposed Land Uses
Retail
50,400 sf
2,160
31
19
50
90
98
188
Hotel
91 rooms
740
31
20
51
29
25
54
Health Club
123,410 sf
4,060
77
93
170
249
187
436
Office
9,784 sf
110
13
2
15
3
12
15
Residential
358 units
2,380
37
146
183
144
78
222
9,450
Total Unadjusted Trips
189
280
469
515
400
915
Adjustments for:
Internal Trips
-620
-13
-13
-26
-32
-32
-64
Transit Trips
-560
-9
-17
-26
-32
-23
-55
Walk/Bike Trips
-240
-4
-7
-11
-13
-11
-24
8,030
TotalAdjusted Vehicle Trips
163
243
406
438
334
772
Existing Land Uses
Retail
10,676 sf
460
7
4
11
19
21
40
Light Industrial
4,032 sf
30
4
0
4
0
4
4
Warehouse
9,991 sf
40
2
1
3
1
2
3
Hotel
91 rooms
740
31
20
51
29
25
54
Health Club
97,700 sf
3,220
61
74
135
197
148
345
Office
77,751 sf
860
106
15
121
20
96
116
5,350
Total Unadjusted Trips
211
114
325
266
296
562
Adjustments for:
Internal Trips
-260
-0
-0
-0
-9
-9
-18
Transit Trips
-260
-6
-6
-12
-14
-15
-29
Walk/Bike Trips
-110
-4
-2
-6
-7
-6
-13
4,720
Total Adjusted Vehicle Trips
201
106
307
236
266
502
Net New Vehicle Trips
3,310
-38
137
99
202
68
270
Source: Heffron Transportation, Inc., February 2012.
3.3. Trip Distribution and Assignment
The PM peak hour trip distribution pattern for this project was derived from trip origin and destination
data obtained from the City of Edmonds travel demand forecasting model. Figure 4 shows the projected
distribution of net new project trips throughout the study area, based on the model data. The forecasted
net changes in project -generated traffic were added the 2025 -without -project traffic volumes to estimate
with -project traffic volumes. These projected volumes are shown on Figure 5.
- 11 - May 21, 2012
Traffic Signal
Stop Sign
+—XX PM Peak Hour Volume
Inbound Trip %
Outbound Trip %
Figure 4
DISTRIBUTION AND ASSIGNMENT
NET NEW PROJECT TRIPS -w 1C
Figure 5
FUTURE (2025) WITH PROJECT
TRAFFIC VOLUMES - PM PEAK HOUR
Harbor Square Redevelopment
Transportation Technical Report
Addendum to SEPA Checklist
3.4. Traffic Operations
heffron
'trans ortat�on, in4a
Levels of service for study area intersections were calculated using the 2025 -with -project traffic
volumes and the methodologies described previously in this report. Table 5 shows the results of the
analysis for the PM peak hour. Levels of service for 2025 -without -project conditions are shown for
comparison. As shown, the project is expected to add delay at the Edmonds Way/Dayton Street
intersection, but it is still expected to operate at LOS B in 2025. The site driveways are expected to
operate at LOS A overall and all turn movements are projected to operate at LOS C or better in 2025
with the project.
Table 5. PM Peak Hour Level of Service - 2025 -Without- and With -Project Conditions
Intersection
2025 Without Project
LOS 1 Delay2
2025 With Project
LOS Dela
Signalized Intersection
Edmonds Way (SR 104) / Dayton Street
A
8.7
B
14.6
Unsignalized Intersections
Dayton Street / North Site Driveway 3
A
4.7
A
6.7
Northbound left- and right- tums from driveway
B
12.1
C
15.8
Westbound left -turns into driveway
A
8.4
A
9.5
Edmonds Way (SR 104) / East Site Driveway4
A
0.8
A
1.0
Eastbound right -turns from driveway
B
12.9
B
13.4
Source: Heffron Transportation, Inc, February 2012
1. Level ofservice.
2. Average seconds of delay per vehicle.
3. Two driveways currently exist on the site at Dayton Street,, driveway volumes were consolidated to one location to reflect a worst
case condition.
4. This driveway intersection is physically restricted to right turn in and right -turn -out movements only, it is expected that any driveway
provided at SR 104 under future conditions would maintain this configuration.
3.5. Transit and Non -Motorized Facilities
As can be determined form Table 4, the proposed redevelopment project is expected to generate at
least 560 transit trips, and over 1,400 non -motorized trips (internal walk trips, external walk/bike
trips, and walk trips to/from transit) per day. As described previously in Section 2.5 Transit, the site is
well served by bus, rail, and ferry service. In addition, the surrounding road network includes a
complete sidewalk network that would accommodate increases in pedestrian demand. Any increases
in non -vehicle modes of travel would be considered a benefit of the project.
3.6. Transportation Concurrency
The potential effect of the proposed land use designation change on the City's concurrency
management system was assessed by comparing the net new trips expected to be generated by the
proposed project to net new trips analyzed in the City's travel demand forecasting model for the
transportation analysis zone (TAZ 11) in which the site is located. Table 6 compares the project's
-14- May 21, 2012
Harbor Square Redevelopment
Transportation Technical Report
Addendum to SEPA Checklist
expected net new trips to those that were modeled for the current Comprehensive Transportation Plan.
As shown, the project is expected to generate more trips than were analyzed in the City's model -99
more inbound trips and 10 more outbound trips.
Table 6. Comparison of Net New Project Trips to Concurrency Model Trips
a. Source: Heffron Transportation, Inc., February 2012.
b. Source: Existing and year 2025 trip tables, TAZ 11, City of Edmonds Travel Demand Forecasting Model, November2009.
As described previously, the PM peak hour trip distribution pattern for the project was derived from
trip origin and destination data obtained from the travel demand forecasting model. Figure 6 shows
the distribution of the additional project trips (over what had been modeled and analyzed previously)
through the seven nearest concurrency intersections. These trips were added to the 2025 model
volumes that were analyzed at each concurrency intersection, with the City's 2025 Transportation
Improvement Program in place. Table 7 summarizes the levels of service at the intersections as
presented in the City Comprehensive Transportation Plan (reflecting the modeled land use) and the
levels of service with the additional project -generated trips.
Table 7. Level of Service Comparison at City Concurrency Intersections
City
ID#
Net New Trips by 2025 over Existing
Inbound Outbound Total
Proposed Project a
City Travel Demand Forecasting (Concurrency) Model - TAZ 11 b
202 trips
103 trips
+99 trips
68 trips
58 trips
+10 trips
270 trips
61 trips
+109 trips
Increase in Expected Project Trips over Concurrency Model Trips
a. Source: Heffron Transportation, Inc., February 2012.
b. Source: Existing and year 2025 trip tables, TAZ 11, City of Edmonds Travel Demand Forecasting Model, November2009.
As described previously, the PM peak hour trip distribution pattern for the project was derived from
trip origin and destination data obtained from the travel demand forecasting model. Figure 6 shows
the distribution of the additional project trips (over what had been modeled and analyzed previously)
through the seven nearest concurrency intersections. These trips were added to the 2025 model
volumes that were analyzed at each concurrency intersection, with the City's 2025 Transportation
Improvement Program in place. Table 7 summarizes the levels of service at the intersections as
presented in the City Comprehensive Transportation Plan (reflecting the modeled land use) and the
levels of service with the additional project -generated trips.
Table 7. Level of Service Comparison at City Concurrency Intersections
City
ID#
Intersection
From City Transportation Plan
With Additional Project Trips 2
2025 LOS 3 Delay4
2025 LOS Dela
4
Puget Drive / 88th Avenue W
A
8
A
8
5
Puget Drive / Olympic View Drive
B
20
B
20
6
Caspers Street / 9th Avenue N
B
13
B
13
11
Main Street / 9th Avenue N
B
16
B
16
12
Walnut Street / 9th Avenue S
A
9
A
10
13
Main Street / 3rd Avenue N
A
9
A
10
17
220th Street SW / 9th Avenue S
B
14
B
14
18
Edmonds Way / 100th Avenue W 5
D
44
D
47
1. Source: City of Edmonds Comprehensive Transportation Plan, November 2009, for conditions with the 2025 Transportation
Improvement Program in place.
2. Source: Heffron Transportation, Inc., February 2012.
3. Level ofservice.
4. Average seconds of delay per vehicle.
5 This intersection is not a City concurrency intersection because Edmonds Way (SR 104) is a Highway of Statewide SigntAcance
and under the jurisdiction of the Washington State Department of Transportation. However, it is monitored by the City.
- 15- May 21, 2012
N
Not to Scale
'er co,") Inbound Trip % Additional Inbound Trip CD Concurrency Intersection #
Outbound Trip % Additional Outbound Trip
Port of Edmonds Figure 6
DISTRIBUTION OF NET NEW PROJECT TRIPS
Harbor Square THAT EXCEED CONCURRENCY MODEL TRIPS
Harbor Square Redevelopment heffron
Transportation Technical Report
Addendum to SEPA Checklist ® . o
As shown in Table 7, the additional project -generated trips are expected to add little or no delay to the
concurrency intersections with planned improvements in place, and would not change any of the
expected levels of service. Therefore, the adopted Transportation Improvement Program is sufficient
to accommodate the additional demand. New development projects implemented with the proposed
land use designation would contribute funding toward the Transportation Improvement Program
roadway improvements through the City's traffic impact fee program. New development made
possible by the proposed amendments is not expected to affect the City's adopted concurrency
management program or trigger a need for any additional roadway improvements.
New development projects implemented with the proposed land use designation would contribute
funding toward roadway improvements that are planned to support city-wide development through
the City's concurrency management and traffic impact fee programs. It is expected that internal
access roads will be proposed as part of project -specific proposals and will be analyzed at the project
level at the time of permitting review. The development projects would also make frontage
improvements as needed to meet City of Edmonds standards. New development implemented
consistent with the proposed land use designation is not expected to trigger a need for additional off-
site roadway improvements
-17- May 21, 2012
FAM Jgi1j191►�I=1
Harbor Square Redevelopment
Transportation Technical Report
Addendum to SEPA Checklist
trans p ortatron, rnc.
Levels of service (LOS) are qualitative descriptions of traffic operating conditions. These levels of
service are designated with letters ranging from LOS A, which is indicative of good operating condi-
tions with little or no delay, to LOS F, which is indicative of stop -and -go conditions with frequent
and lengthy delays. Levels of service for this analysis were developed using procedures presented in
the Highway Capacity Manual (Transportation Research Board, 2010).
Level of service for signalized intersections is defined in terms of delay. Delay can be a cause of driver
discomfort, frustration, inefficient fuel consumption, and lost travel time. Specifically, level of service
criteria are stated in terms of the average delay per vehicle in seconds. Delay is a complex measure and
is dependent on a number of variables including: the quality of progression, cycle length, green ratio,
and a volume -to -capacity ratio for the lane group or approach in question. Table A-1 shows the level of
service criteria for signalized intersections from the Highway Capacity Manual.
Table A-1. Level of Service Criteria
Level of Service
A Less than 10.0 Seconds
B 10.1 to 20.0 seconds
C 20.1 to 35.0 seconds
D 35.1 to 55.0 seconds
E 55.1 to 80.0 seconds
F Greater than 80.0 seconds
Source: Transportation Research Board, WwayQga&Man ual, 2010.
Free flow
Stable flow (slight delays)
Stable flow (acceptable delays)
Approaching unstable flow (tolerable delay—
occasionally wait through more than one
signal cycle before proceeding.
Unstable flow (approaching intolerable delay)
Forced flow (jammed)
For unsignalized intersections, level of service is based on the average delay per vehicle for each
turning movement. The level of service for a two-way, stop -controlled intersection is determined by
the computed or measured control delay and is defined for each minor movement. Delay is related to
the availability of gaps in the main street's traffic flow, and the ability of a driver to enter or pass
through those gaps. The delay at an all -way, stop -sign (AWSC) controlled intersection is based on
saturation headways, departure headways, and service time using procedures in Chapter 17 —
Unsignalized Intersections, Applications —AWSC Intersections of the Highway Capacity Manual
2010 (Transportation Research Board (TRB), 2010). Table A-2 shows the level of service criteria for
unsignalized intersections from the Highway Capacity Manual.
Table A-2. Level of Service Criteria for Unsignalized Intersections
Average Delay
Level of Service
A
Less than 10.0
B
10.1 to 15.0
C
15.1 to 25.0
D
25.1 to 35.0
E
35.1 to 50.0
F
Greater than 50.0
Source.' Transportation Research Board, Highway Capacit My anual, 2010.
A-1