HomeMy WebLinkAboutTIS 2022-11-21 COMPLETE AGENDA PACKETCity of Tukwila
Transportation and
Infrastructure Services
Committee
.•.
•:•
Kate Kruller, Chair
Mohamed Abdi
❖ Tosh Sharp
AGENDA
Distribution:
K. Kruller
C. Hougardy
T. Sharp
H. Ponnekanti
S. Kim (email)
G. Lerner (email)
City Attorney (email)
Clerk File Copy
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MONDAY, NOVEMBER 21, 2022 — 5:30 PM
HYBRID MEETING — ONSITE AND VIRTUAL
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Next Scheduled Meeting: December 5, 2022
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Item
Recommended Action
Page
1.
PRESENTATIONS
2.
BUSINESS AGENDA
a) Neighborhood Traffic Calming Program
a)
Discussion only
Pg. 1
Project Update (C. Knighton)
b) Transportation Analysis for Temporary One -Way
b)
Discussion only
Pg. 17
Operations of the 42nd Ave. S Bridge
(H. Ponnekanti)
c) Public Works Campus, Phase 2 (B. Miles)
c)
Discussion only
3.
MISCELLANEOUS
Next Scheduled Meeting: December 5, 2022
The City of Tukwila strives to accommodate individuals with disabilities.
Please contact the Public Works Department at 206-433-0179 for assistance.
City of Tukwila
Allan Ekberg, Mayor
Public Works Department - Harr Ponnekanti, Director/City Engineer
INFORMATIONAL MEMORANDUM
TO: Transportation and Infrastructure Services Committee
FROM: Hari Ponnekanti, Public Works Director
BY: Joshua Hartley, Deputy Director of Public Works
Cyndy Knighton, Senior Program Manager
CC: Mayor Ekberg
DATE: November 18, 2022
SUBJECT: Neighborhood Traffic Calming Program
Project No. 80010301
Project Update
ISSUE
Provide a status update to Council for the Top 10 List in the Neighborhood Traffic Calming Program
(NTCP), including the Allentown Neighborhood Transportation Study Update.
BACKGROUND
In 2021, the Council reinstated the full $400,000 budget for 2022 by using ARPA funding made
available to the City from the Federal Government. Public Works presented a Staff Top 10
Recommended NTCP Projects List that would utilize this funding. As of October 2022, Public Works
has encumbered roughly $374,000 on projects identified in the Top 10 List. The remaining balance
($26,000) will be spent on replenishing normal stock items used in traffic calming such as street
signs, luminaires, speed feedback signs, speed cushions for future installation, etc.
DISCUSSION
This year, three NTCP projects have been completed, and three more are well underway. Project A
— Allentown Neighborhood Speed and Safety Study, Project E — Tukwila Community Center
Pedestrian Crossing Safety Improvements and Project J — S 144th Street/46th Avenue S ADA Ramps
have all been completed.
The Allentown Neighborhood Transportation Study was completed in October 2022. At the March
2022 and April 2022 Allentown Community meetings, the draft study was shared with residents and
businesses, and feedback was collected to help determine traffic calming recommendations for the
neighborhood. There are at least nine recommendations provided in the attached report. The
recommendations include speed limit reductions on 115th, additional signage and pavement
markings, installing rectangular rapid flashing beacons (RRFBs), additional crosswalks, intersection
geometry improvements at S. 124th Street and 50th Place S., speed cushions, and other traffic calming
measures. Public Works is reviewing the report now and developing potential scope of work for future
projects.
The City is actively searching and applying for grants to fund the recommendations identified in the
Allentown Neighborhood Transportation Study. An application was submitted to the Washington State
Department of Transportation's Pedestrian and Bicycle Improvements grant for a raised crosswalk,
1
Traffic Calming Program Info Memo
Page 2
curb bulb outs, and an RRFB at the S 119th street bridge crossing on 42nd Ave S, which was a
recommended improvement in the study. The City was recently notified by WSDOT that this project
has been identified as a tier one funding priority. The City will be notified in early 2023 if the project
is selected for funding.
NTCP projects that are still underway include: Project B — Tukwila Elementary School Safety
Improvements, Project C — Impact Charter School Safety Improvements and Project D — Cascade
View Elementary School Safety Improvements. Each of these projects have completed preliminary
planning studies and are awaiting coordination with the individual schools before moving to final
design of the recommended improvements. Each site has specific challenges and operations that
need to be discussed to ensure appropriate design elements are considered and that specific needs
are met.
FINANCIAL IMPACT
Projects on the Staff Top 10 List, including the recommendations made in the attached study, are
now anticipated to cost at least $1.2 million, potentially higher, based on the recommendations from
projects such as Macadam Road and S. Ryan Way. Some of these costs can be borne by the existing
$400,000 annual budget, and Public Works staff are actively applying for grants where possible to
provide additional funding for future projects in the Top 10 List.
RECOMMENDATION
For Discussion Only.
ATTACHMENTS: Top 10 Recommended NTCP Projects List Updated 11-04-22
Top 10 Recommended NTCP Projects Map
Final Allentown Transportation Analysis
2
Staff Top -10 Recommended NTCP Projects
Modified 11/2/2022
Project
Details
Potential Treatment Options
Status
Complete?
Original Cost Range
Estimate
Updated Cost
Estimate
A
Allentown Neighborhood Speed
and Safety Study
Since 2018, five individual requests for traffic calming have been recorded in the NTCP list of requests; however, traffic
complaints have been made to the City over prior years. Addressing traffic safety concerns in Allentown is a top priority for the
City.
PW Staff reviewing
recommendations and
developing scope of work for
future projects.
Yes
$50,000-80,000
$20k for study
$640k for CN of
study
recommendations
Study neighborhood -wide volume, speed, classification and
safety issues. Design plan for Level 1 and Level 2 treatments
throughout Allentown.
Level 1: Improved signage; radar feedback signs; pavement
marking modifications
Level 2: Curb extensions
B
Tukwila Elementary School
Safety Improvements
Since 2018, 12 traffic calming requests have been made in the Cascade View neighborhood, with a significant number of them
near Tukwila Elementary School. Common complaints have been over speeding and crosswalk or pedestrian safety.
Additionally, the Council has asked for proactively addressing or anticipating concerns, specifically around school zones. Some
improvements have been made around Tukwila Elementary School already but more improvements are needed.
Have reached out to Tukwila
School District/Tukwila
Elementary School staff to
gain understanding of
operations and challenges.
Improvements will be made
in 2023.
Underway
$30,000-80,000
TBD
Address speeding and crosswalk safety concerns.
Level 1: Improved signage; radar feedback signs; pavement
marking modifications
Level 2: Curb extensions; RRFB installation; ADA ramp upgrades;
improved illumination
C
Impact Charter School Safety
Improvements
A request specific to the newly opened Impact Charter School was received in 2019. The request was to provide a signed school
zone, which Tukwila has provided along with signs marking school crossings on S 148th Street. ADA -compliant ramps have not
been installed at the marked school crossings. The charter school has expanded their site to the north with a need for
consideration of a school zone on 5 146th Street and other potential improvements for children's safety. Additionally, the
Council has asked for proactively addressing or anticipating concerns, specifically around school zones.
Awaiting a proposed private
development for possible
ADA ramp improvement.
Underway
$8,000-15,000
TBD
Provide school crossing improvements, establish school zone
on S 146th Street, if needed. Provide school crossing
improvements, observe operating speeds, if necessary
establish speed zone.
Level 1: Improved signage for school zones on S 148th Street and
S 146th Street; crosswalk installation
Level 2: ADA ramp improvements; curb extensions
D
Cascade View Elementary
School Safety Improvements
Since 2018, the Tukwila Hill neighborhood has seen 9 requests for traffic calming. Four of the locations are around the
speeding, school crossing and pedestrian safety around the Cascade View Elementary School. 85th Percentile speeds of
—30MPH in the 25MPH zones have been recorded, but analysis to separate whether the speeding is even more than the posted
school zone has not been done. Additionally, the Council has asked for proactively addressing or anticipating concerns,
Study for improved signage
and crosswalk underway
Design for ADA
improvements later in year
with construction likely in
2023
Underway
$8,000-15,000
TBD
Upgrade School Zone signing, design and install pedestrian
crossing improvements.
Level 1: Improved signage for school zones on S 148th Street and
S 146th Street; crosswalk installation
Level 2: ADA ramp improvements; curb extensions
E
Tukwila Community Center
Pedestrian Crossing Safety
Improvements
The City Council has expressed desire for the NTCP to have a proactive element in addressing traffic calming and safety needs
throughout the City. The TCC is a well -utilized facility by the Allentown neighborhood as well as the entire City and surrounding
area. Concerns over the pedestrian crossings on 5 124th Street have been raised by staff and residents in the past, along with
the larger complaints of speeding in Allentown. Increasing pedestrian visibility to improve safety in this high -use area is a
recommended top priority for the NTCP.
Complete
Yes
$80,000-100,000
$15k PE
$47k RRFB units
$78k RRFB
Installation
Design and install mid -block pedestrian safety improvements
on S 124th Street.
Level 1: Improve pedestrian crossing signage
Level 2: RRFB installations; upgrade ADA ramps; curb extensions;
improved illumination
F
Macadam Road Speed and
Safety Improvements
At least five requests for traffic calming, specific to speeding (and some secondary reasons) have been made since 2018. A
radar feedback sign was placed near the 13700 block in 2019 but requests have continued to be made. Additional analysis is
warranted to determine what other improvements could be used to address the speeding, especially where Macadam has
extremely limited sight distance due to the curvy nature of the roadway.
Individual Project to begin
design 10 2023.
$10,000 - 30,000
TBD
Design and install treatments addressing speeding and curve
safety north of S 144th Street.
Level 1: Improved signage; LED chevron signs; channelization
modifications
Level 2:
3
Staff Top -10 Recommended NTCP Projects
Modified 11/2/2022
r._�_:E.
Original Cost Range
Updated Cost
G
Southcenter Boulevard/65th
Avenue S Pedestrian Safety
Improvements
Staff identified the need for improvement pedestrian safety at this location several years ago. Southcenter Boulevard is a 5 -lane
roadway with known speeding issues along with curves that restrict sight distance. A high pedestrian usage at this intersection
accessing the King County Metro bus stop that services both the Rapid Ride F -Line and Route 150, both workhorses of the south
County transit network, justifies improving pedestrian crossing safety. This intersection is slated for full signalization in the
future, but interim pedestrian safety improvements should be considered sooner.
Funding available for design
of full signal in 2022 CIP.
Design to begin in 2022.
Recommended
improvements will be
incorporated into signal
project in the CIP.
$50,000-$90,000
TBD
Design and install pedestrian safety improvements
Level 1: Improved signage for pedestrian crossing
Level 2: RRFB installation; ADA ramp upgrades; improved
illumination
H
City-wide Residential Speed
Limit Review
As part of the City Council's expressed desire to proactively look at traffic calming needs, a full review of the residential street
posted speed limits is recommended by staff. State law establishes city speed limits at 25MPH unless an engineering study is
completed to justify higher speed limits. Most residential streets are posted at 25MPH today, but there are many that are
posted at 30MPH or 35MPH. Likely, those speed limits are legacies of past annexation areas, where a speed study was
completed by King County. The general impression Staff has is that most residents and elected officials would be happier with
lower speed limits. City of Seattle has also recently lowered all speed limits nearly city-wide to be 25MPH.
Reviews to begin in early
2023.
$5,000-8,000
TBD
Identify residential streets with speed limits currently above
25MPH. Conduct volume, speed and safety review.
Recommend changes to speed limits, as necessary.
Level 1: Modify speed limit ordinance; as needed; install new
signs; as needed.
Level 2:
S Ryan Way Pedestrian Safety
Improvements
Two requests for traffic calming to address speeding and pedestrian crossing safety in the Ryan Hill area have been made in
2021. New developments are coming forward that will increase the residential population of this part of the City with multi
family developments. The speed concerns, especially along S Ryan Way, coupled with the new housing developments increasing
the likelihood of increased pedestrian activity, warrants this analysis be recommended as a top priority.
planning and Design to begin
in early 2023. Will be stand
alone project based on
recommendations provided
by the designer.
$10,000-100,000
TBD
Safety study on S Ryan Way from MLK Jr. Way to east city
limits, focusing on speeding and pedestrian safety.
Recommend Level 1 and Level 2 improvements. Design and
construct improvements.
Level 1: Improved signage
Level 2: Curb extension, improved illumination
J
S 144th Street/46th Avenue S
ADA Ramps
The Tukwila School District requested school crossing safety improvements at this intersection in 2017. A new Rectangular
Rapid Flashing Beacon was installed in early 2019. At the time the RRFB was installed, the City was also submitting a grant
application for the 46th Avenue S Safe Routes to School project, which would improve pedestrian safety between this
intersection south to S 150th Street, and would include either a raised pedestrian crosswalk at the RRFB or install ADA -
compliant curb ramps. The grant was not awarded. State law requires ADA ramps be brought up to current standards anytime
a new signal, including the RRFB, is installed. Since grant monies for the larger improvement are not expected in the short term,
staff recommends this as a priority to comply with all state and federal laws regarding Americans with Disabilities Act
Complete
Yes
$15,000-20,000
$15k PE
$90k Construction
Design and install ADA -compliant ramps at the intersection.
Level 1:
Level 2: ADA upgrades to ramps at RRFB (not done at time of
RRFB installation due to budget constraints)
4
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8
Vicinity Map
King County
U:\PW Eng\GIS General Maps \Streets_11 x17_Sept2018.mxd
Date: 09/09/18 By: R. Linsao
Disclaimer:
The location of features and boundaries
are approximate and are intended for
reference only. Data is based on best
information available.
P
PSOMAS
Memorandum
To: Public Works Department, City of Tukwila
From: KPG Psomas
Date: October 10, 2022
Re: Allentown Neighborhood Transportation Study
The City has received several requests for traffic calming from citizens in the Allentown
Neighborhood. As part of the Neighborhood Traffic Calming Program, the City hired KPG Psomas
to evaluate existing roadway and non -motorized facilities, adjacent land uses, vehicle speeds,
vehicle volumes, signage, and five years of historical crash data. KPG Psomas and City staff met
with the Neighborhood several times to understand their issues and concerns, hear feedback on
potential improvements, and share recommended improvements. Based on this analysis and
community input, KPG Psomas and the City developed a set of recommended improvements to
calm traffic, improve safety, and enhance pedestrian mobility.
The approximate boundaries of the Allentown Neighborhood are the Duwamish River to the south
and west, S 115th Street to the north, and 1-5 to the east. The primary land uses in the
Neighborhood are residential, Tukwila Community Center, and BNSF Railway Intermodal facility.
Figure 1 shows a map of the Allentown Neighborhood study area.
Street Network
Due to the Duwamish River, BNSF Railroad tracks, and 1-5 being located around the perimeter of
the Allentown Neighborhood, there are only three vehicle access points to the Neighborhood at S
115th Street, 42nd Avenue S bridge over the Duwamish River, and 50th Place S that connects to S
129th Street. S 129th Street provides one of the few crossings of the BNSF Railroad tracks and I-5
in the area.
There are two street classification types in the Allentown Neighborhood: Collector Arterials and
Local Streets. The Collector Arterials are S 115th Street, 42nd Avenue S, S 124th Street, and 50th
Place S. The Collector Arterials are intended to carry the majority of the traffic through the
Neighborhood. Local Streets are intended to provide circulation and access to adjacent properties.
Except for local access, trucks are restricted on S 115th Street and the segment of 42nd Avenue S,
north of S 124th Street.
Truck Traffic
The BNSF Railway Intermodal facility is located along the eastern boundary of the Neighborhood
with its primary access on S 124th Street at 51st Place S. This facility generates a high volume of
truck traffic as containers are transferred between trains and trucks. Baker Commodities, a
3131 Elliott Avenue, Suite 400, Seattle, WA 98121 206.286.1640
www.kpg.com
6
rendering plant, also generates truck trips along S 124th Street and 50th Place S as the only access
to the plant is from Railroad Avenue S which intersects 50th Place S at the southeast corner of the
Neighborhood. There are other manufacturing and industrial businesses in the Neighborhood
along 44th Place S and 51st Place S that generate truck traffic and trucks must use Local Streets to
access these businesses.
Figure 1. Allentown Neighborhood Study Area
PEDESTRIAN
BRIDGE
TRAFFIC DATA COLLECTION
LOCATION N
H COLLECTOR ARTERIALS
A
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Related Projects in Allentown
Allentown Truck Reroute Project
This project is evaluating potential alternative routes to access the BNSF Railway Intermodal
facility. Alternatives include maintaining the existing access at S 124th Street or relocating the
access to the north or south. An Environmental Impact Statement (EIS) is currently being prepared
to assess the impacts of each alternative, and recommend a preferred access location.
Replacement of 42nd Avenue S bridge over Duwamish River
The 42nd Avenue S bridge over the Duwamish River connects the Allentown Neighborhood with
Interurban Avenue S. In December 2021, the bridge was damaged by an over -height truck load and
was closed to all modes of travel pending repairs. The existing bridge is considered structurally
deficient and the bridge is currently only open in the southbound direction. The City is designing a
new bridge that will be constructed at the same location.
Traffic Calming
Traffic calming uses information, educational, and physical improvements and other strategies to
slow vehicle speeds and improve safety through neighborhood areas. Traffic calming treatments
include signs, striping and pavement markings (paint), on -street parking, narrowing the roadway,
raised curb, curb bulbs, chicanes, roundabouts, center medians, speed cushions, raised crosswalks,
and other treatments. The decision on whether to install traffic calming should consider the
potential for diverting traffic to parallel routes, emergency vehicle response times, type of vehicles
using the roadway, travel delay, and neighborhood support.
For collector arterial streets such as S 115th Street, 42nd Avenue S, S 124th Street, and 50th Place
S, KPG Psomas does not recommend the installation of speed humps or cushions for the following
reasons:
• Inappropriate for collector arterials which are intended to carry the majority of traffic.
• Potential for vehicles to shift from arterials to parallel local streets.
• Negative impacts to emergency vehicle response times (including Tukwila Fire Station 53).
• Noise impacts to homes due to vehicles crossing cushions, braking and accelerating.
• Not compatible with truck operations that access existing businesses in the Neighborhood.
Analysis Findings and Recommended Improvements
Transportation volume and speed data were collected from 2020 to 2022 during the COVID-19
pandemic when traffic volumes were potentially lower due to more people working from home
and fewer people traveling for social and recreational activities. The 42nd Avenue S bridge over
the Duwamish River was closed for repairs when the 2022 traffic data was collected on 42nd
Avenue S, north of S 124th Street. As part of the analysis, KPG Psomas also evaluated five years of
historical crash data. A summary of the crash data is provided in Appendix A.
The following sections describe the characteristics of individual streets in the Neighborhood and
the recommended improvements to calm traffic, improve safety, and enhance pedestrian
mobility. Figure 2 shows the recommended improvements. The implementation of these
improvements will depend on available funding for design and construction. Cost estimates for the
recommended improvements are included in Appendix B.
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Figure 2. Allentown Neighborhood Recommended Improvements
S 115th Street
RECOMMENDED N
IMPROVEMENTS A
COLLECTOR ARTERIALS
Street Classification
Collector Arterial
Speed Limit
30 mph
Eastbound Average Vehicle Speed
21 mph
Eastbound 85th Percentile Vehicle Speed
36 mph
Westbound Average Vehicle Speed
21 mph
Westbound 85th Percentile Vehicle Speed
36 mph
Note: Data collected July 2020.
4 of 8
9
S 115th Street runs east -west between East Marginal Way S
and 42nd Avenue S. The street provides access to the
Duwamish Hill Preserve and the Allentown Neighborhood.
There is a sidewalk on the north side of the street.
Recommended Improvements
A. Speed limit reductions — lower the speed limit on S
115th Street from 30 mph to 25 mph to lower speed
entering the Allentown Neighborhood and to be
consistent with the speed limit on 42nd Avenue S. On
East Marginal Way approaching the 115th Street
intersection, install 25 mph advisory speed limit signs to
warn drivers of turning vehicles.
42nd Avenue S
East Marginal
intersection
Way and S 115th Street
Notes: 'Data collected 1/13/2022-1/22/2022 when 42nd Avenue S bridge over Duwamish River was closed.
2 Data collected August 2021.
42nd Avenue S runs along the Duwamish River with
residential homes along the east side of the street.
There is a pedestrian bridge crossing of the river at
S 119th Street and the Duwamish Park is located at
approximately S 117th Street. A continuous
sidewalk runs along the east side of the street
between S 115th Street and Interurban Avenue S,
except for a missing segment at the S 124th
Street/42nd Avenue S intersection. The 42nd
Avenue S corridor experienced 10 crashes during
the five-year study period.
Recommended Improvements
42nd Avenue S at S 119th Street (looking north)
B. 25 mph pavement markings — paint 25 mph markings on southbound 42nd Avenue S, south
of S 115th Street and on northbound 42nd Avenue S, north of S 124th Street.
C. Improved pedestrian crossing and traffic calming — construct a Rectangular Rapid Flashing
Beacon (RRFB) system, raised crosswalk, curb bulbs, and ADA sidewalk improvements at
the S 119th Street pedestrian bridge crosswalk to shorten the pedestrian crossing distance,
narrow travel lanes, and calm traffic.
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Segment north of
S 124th Street1
Segment south of
S 124th Street'
Street Classification
Collector Arterial
Collector Arterial
Speed Limit
25 mph
25 mph
Northbound Average Vehicle Speed
31 mph
25 mph
Northbound 85th Percentile Vehicle Speed
36 mph
30 mph
Southbound Average Vehicle Speed
31 mph
23 mph
Southbound 85th Percentile Vehicle Speed
36 mph
29 mph
Average Weekday Traffic Volume
3,900
9,300
Notes: 'Data collected 1/13/2022-1/22/2022 when 42nd Avenue S bridge over Duwamish River was closed.
2 Data collected August 2021.
42nd Avenue S runs along the Duwamish River with
residential homes along the east side of the street.
There is a pedestrian bridge crossing of the river at
S 119th Street and the Duwamish Park is located at
approximately S 117th Street. A continuous
sidewalk runs along the east side of the street
between S 115th Street and Interurban Avenue S,
except for a missing segment at the S 124th
Street/42nd Avenue S intersection. The 42nd
Avenue S corridor experienced 10 crashes during
the five-year study period.
Recommended Improvements
42nd Avenue S at S 119th Street (looking north)
B. 25 mph pavement markings — paint 25 mph markings on southbound 42nd Avenue S, south
of S 115th Street and on northbound 42nd Avenue S, north of S 124th Street.
C. Improved pedestrian crossing and traffic calming — construct a Rectangular Rapid Flashing
Beacon (RRFB) system, raised crosswalk, curb bulbs, and ADA sidewalk improvements at
the S 119th Street pedestrian bridge crosswalk to shorten the pedestrian crossing distance,
narrow travel lanes, and calm traffic.
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S 124th Street
Street Classification
Collector Arterial
Speed Limit
25 mph
Eastbound Average Vehicle Speed
27 mph
Eastbound 85th Percentile Vehicle Speed
33 mph
Westbound Average Vehicle Speed
27 mph
Westbound 85th Percentile Vehicle Speed
33 mph
Average Weekday Traffic Volume
8,100
Note: Data collected July and August 2021.
S 124th Street provides access to single family homes,
Tukwila Community Center, and BNSF's Intermodal
facility at the east end of the street. There is curb and
sidewalk along the frontage of the Community Center
and the north side of the street has a pedestrian
walkway with segments of extruded curb that provide a
buffer from the roadway between 42nd Avenue S and
49th Avenue S. An eastbound vehicle speed radar
feedback sign is located at 45th Avenue S. S 124th
Street experienced 8 crashes during the five-year study
period. In 2019, there was a fatal vehicle -pedestrian
crash at the S 124th Street/46th Avenue S intersection.
Recommended Improvements:
S 124th Street at 46th Avenue S (looking west)
D. Improved pedestrian crossings — install Rectangular Rapid Flashing Beacon (RRFB) systems
at 44th Avenue S (Community Center driveway) and 46th Avenue S. Construct raised curbs
and sidewalks to separate pedestrians and vehicles, narrow the pedestrian crossing
distance, and provide traffic calming.
E. North side pedestrian walkway between 49th Avenue S and 51st Place S — construct a
continuous pedestrian walkway along north side of S 124th Street.
F. Reconfigure S 124th Street/50th Place S
intersection - remove eastbound right turn slip
lane to calm traffic and improve safety. Currently
eastbound right turning vehicles are not
required to stop. Reconfigure the intersection
with single -lane approaches and require all
vehicles to stop.
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S 124th Street/50th Place S intersection
11
S 125th Street
S 125th Street is a local street along the Duwamish River that connects between 46th Avenue S
and 50th Place S. Residents along the street have expressed concerns regarding speeding and cut -
through traffic. There have been 3 crashes at the S 125th Street/50th Place S intersection over the
last 5 years. This intersection is just south of the S 124th Street/50th Place S intersection, which
has an eastbound right turn slip lane that does not require vehicles to stop.
Recommended Improvements
G. Speed cushions — continue to monitor vehicle speeds and volumes in order to evaluate
potentially installing speed cushions. Coordinate with residents along S 125th Street to
determine if they support speed cushions. Speed cushions could be an appropriate
treatment along this street because there is not a parallel local street that could be
impacted by diverting traffic.
50th Place S
Street Classification
Collector Arterial
Speed Limit
25 mph
Northbound Average Vehicle Speed
32 mph
Northbound 85th Percentile Vehicle Speed
36 mph
Southbound Average Vehicle Speed
33 mph
Southbound 85th Percentile Vehicle Speed
39 mph
Average Weekday Traffic Volume
7,300
Note: Data collected July and August 2021.
50th Place S connects between S 124th Street and S
129th Street. S 129th Street crosses the BNSF tracks
and 1-5, and is the southeast entrance to the Allentown
Neighborhood. 50th Place S serves residential
properties and Codiga Park along the Duwamish River.
There is a segment of sidewalk on the west side of the
street along the Park's frontage. The eastside of the
street has a striped paved shoulder that has a few
segments of extruded curb that provide separation
from vehicles.
Recommended Improvements
50th Place S, looking south
H. Pedestrian walkway — construct a continuous pedestrian facility on either the west or east
side of the street.
I. Northbound vehicle radar feedback sign — add a feedback sign at Railroad Avenue, where
50th Place S enters the Allentown Neighborhood.
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Local Streets
Within the Allentown Neighborhood, the local streets are low-volume streets that provide access
to homes and businesses. These local streets typically do not include formal pedestrian facilities
and on -street parking is typically allowed.
Recommended Improvements
J. Reduce default speed limit from 25 mph to 20 mph for local streets — this could be part of a
citywide speed limit reduction effort.
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Appendix A.
Allentown Neighborhood Crash Data by Corridor — 5 Year Period
Corridors
Rear end
Sideswipe
Head On
Left Turn
CU
a
Fixed Object
Exits Roadway
Pedestrian
Pedal -cyclist
Other
TOt
1-
42nd Ave S
3
1
4 (1)
1 (1)
1
10 (2)
S 124th St 1
1
1
2
2
1 (1)
1
8 (1)
50thPIS2
1
1
2
4
46th Ave S
1
2
3
S122ndSt
1
1
2
S 125th St
1
1
2
S 115th St
1
1
S 116th St
1
1
45th Ave S
1
1
Total
2
1
1
6
5
11 (1)
1 (1)
1 (1)
0
4
32 (3)
Source: WSDOT crash data from (9/10/2016 - 9/9/2021).
Notes: (#) indicates severe (fatality or serious injury) crashes.
1 Crashes at the 42nd Avenue S/S 124th Street intersection are included with the 42nd Avenue S corridor.
2 Crashes at the S 124th Street/50th Place S intersection are included with S 124th Street corridor.
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Appendix B.
Cost Estimates Summary
ID
Project
Cost Estimate
A
S 115th Street - Speed limit reduction from 30 mph to 25 mph
$2,000
B
42nd Avenue S — Two 25 mph pavement markings
$5,500
C
42nd Avenue S — RRFB system with raised crosswalk and curb bulbs
at S 119th Street
$245,000
D
S 124th Street — Improved crosswalks with RRFBs and curb bulbs at
44th Avenue S and 46th Avenue S [COMPLETE 2022]
$70,000
E
S 124th Street — North side pedestrian walkway between 49th
Avenue S and 51st Place S
$624,000
F
S 124th Street — Reconfigure S 124th Street/50th Place S intersection
to single -lane approaches and all -way stop control
$750,000
G
S 125th Street — Speed cushions ($5,000 each)
$10,000
H
50th Place S — Continuous pedestrian facility
$185,000
I
50th Place S — Northbound vehicle radar feedback sign
$10,000
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Memorandum
To: Public Works Department, City of Tukwila
From: KPG Psomas
Date: November 11, 2022
Re: Transportation Analysis for Temporary One -Way Operations of the 42nd Ave. S Bridge
Introduction
The 42nd Ave. S bridge over the Duwamish River connects the Allentown Neighborhood with
Interurban Ave. S. In December 2021 the bridge was damaged by an over -height truck load and
was closed to all modes of travel. The City is designing a replacement bridge that will be
constructed in the same location.
Repairs to the bridge allowed it to open with load restrictions that would accommodate only
one-way travel, and on April 4th, 2022, the bridge was reopened in the southbound direction
only. The bridge is expected to continue to be open to one-way travel for the next 20 months,
when completion of a temporary bridge will allow travel in both directions. A new permanent
bridge is scheduled to open in late 2024 or in 2025.
Six months have passed since the repaired 42nd Ave. S bridge was reopened, and the City has
requested a reevaluation of the decision to operate the bridge with southbound -only traffic.
Traffic Volumes
Traffic counts of the bridge that were conducted from October 19th -25th, 2022 showed that
approximately 3,200 vehicles per weekday use the bridge in the southbound direction. The
counts also showed that 28 vehicles per weekday are illegally driving northbound across the
bridge, mostly at off peak times (7:00 pm to 4:00 am) when southbound traffic on the bridge is
lower. If bridge traffic direction was switched to the northbound direction, we expect that a
similar number of vehicles would illegally cross the bridge in the southbound direction.
Traffic Analysis
Currently, southbound traffic on the bridge can use the traffic signal at the 42nd Ave.
S/Interurban Ave. S intersection to exit the neighborhood, providing a protected signal phase
that allows southbound vehicles to efficiently and safely access Interurban Ave. S, or travel south
on Macadam Road S.
We analyzed traffic conditions for northbound -only traffic on the bridge. This would require the
3,200 vehicles per weekday currently traveling southbound on the bridge to drive north and exit
the Allentown neighborhood at the S 115th Street/East Marginal Way S intersection. This
intersection is unsignalized, north -south traffic on East Marginal Way S having the right of way.
Westbound vehicles on S 115th Street have a stop sign and are required to find gaps in both
3131 Elliott Avenue, Suite 400, Seattle, WA 98121 206.286.1640 www.kpg.com
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directions of traffic before turning left and traveling southbound on East Marginal Way S.
Currently, the westbound intersection approach operates at level of service (LOS) B during both
the AM and PM peak hours. Changing the bridge to northbound -only travel would significantly
increase the number of westbound left -turning vehicles at the S 115th Street/East Marginal Way
S intersection. This would result in increased delays and queuing, and the intersection worsening
to LOS F during both the AM and PM peak hours. In addition, westbound drivers at the S 115th
Street/East Marginal Way S intersection have limited sight distance to the south, making it more
difficult to turn left onto southbound East Marginal Way S.
Recommendation
We continue to recommend that the 42nd Ave. S bridge operate in the southbound -only
direction for the next 20 months until a temporary bridge is built. In comparison to exiting the
neighborhood at the unsignalized S 115th Street/East Marginal Way S intersection, using the
traffic signal at the 42nd Ave. S/Interurban Ave. S intersection is safer and more efficient.
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