designing for streets with purpose
TRANSCRIPT
Date (xx/xx/xxxx) Department Name Page NumberSeattle Department of Transportation 1Seattle Department of Transportation
Designing for Streets with Purpose
Dongho ChangCity Traffic EngineerCity of Seattle
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Presentation Overview
• Background / Trends
• Street Typologies
• Street Examples
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Seattle Background• 217 sq km, 730,000 people
• Largest city in King County6,000 sq km, 2.2 m people
• 26% of Seattle land area is in public street right-of-way
• 97.5% of Seattle’s population lives within ¼ mile (0.4 km) of a transit stop
• Ranks 6th of the 50 largest cities for walkability
• Typical arterial roadway width is 60-66’ (18-20 meters)
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Seattle Background• Population 23%
• Collisions -21%, ADT -5%
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Seattle Background• Transit Ridership 46%
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Seattle Ridership Comparison
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Seattle
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Seattle is growing
5th and Columbia – 48 story tower528,000 SF Office Space
184 Room Hotel~300 Parking Garage
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Seattle is growing
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Setting the Policy Foundation
“Because Seattle is a fully built
city with a mature street system,
the City uses a full range of non-
single occupant vehicle
transportation facilities to
support the desired
redevelopment pattern within
Urban Villages”…
- 2004 Comprehensive Plan Update
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Comprehensive Plan Transportation Element key themes
Use right-of-way for multiple purposes
10
Safe, reliable,
affordable, equitable,
and high quality
travel options
Ensure goods
movement
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• Focus growth to more efficiently serve it Urban centers
Manufacturing & industrial centers
Urban villages
• 80% of city growth in centers/villages since 1994
• Future Comprehensive Plan growth targets 2016-2035• 70,000 additional housing
units• 115,000 additional jobs
Seattle’s Growth Strategy
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Seattle’s Growth Strategy
• State Growth Management Act (GMA) requires: • Comprehensive plans to address growth
• Level-of-service standards (LOS) to gauge transportation system performance
• GMA concurrency: allow development if:• LOS is met
• Or commitments are in place to ensure system capacity within 6 years
• Puget Sound Regional Council (MPO)• Certifies local comprehensive plan certification
• Wants multi-modal LOS emphasizing people-moving capacity
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Level of Service: V/C to Modeshare
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Measuring Space efficiency
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200 people can fit in…
177 cars 3 buses
1 light rail train on their bikes
2nd Avenue in Seattle
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Employment Density
301,000 235,000
2018 PSRC Estimates
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Employment Density
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Seattle’s Safety Trends
• One of safest cities in US
• 25% reduction fatalies from 2017 to 2018
• 14 fatalities
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Safety Trends
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Street Types
• Supplementsfunctional classification
• Provides street functionfor support land useand people
• Vision for street
25-35 mph(40-55 kph)
20-30 mph(30-50 kph)
15-20 mph(25-30 kph)
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26.5m
27.4m
~ 1m
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2nd Ave
• Principal Arterial
• DowntownDesign Standards
• 25 mph (40 kph)
25 mph(40 kph)
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• Two-wayPBL
• Bus OnlyLane
• Flex CurbLane
2nd Ave
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• Focus made at Intersection
• Signal separationof turning cars
• Reduced pedestrianleft turn crashes by80%
• Plant/Railing forpeople comfort
2nd Ave
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• More families travellingaccessing downtown by walkingand biking
2nd Ave
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Dexter/7th Ave
• Downtown Neighborhood
• DowntownDesign Standards
• 25 mph (40 kph)
25 mph(40 kph)
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• 2011 Paving Project
• 1.5 Miles (2.3 km) in Length
• 4 lanes to 2 lanes
• Bus and Bike Improvements
Dexter Avenue
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In-lane Transit Islands
Before
After
Before
After
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• 19% increase in traffic volume
• 11,800 AWDT Before
• 14,100 AWDT After
• 19% decrease in collision rate
• ~40% increase in bus ridership
• Bus travel time approximately same (+0.4 sec)
Results
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Dexter Avenue
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Dexter Avenue
0
50
100
150
200
250
300
350
400
Sale
s In
de
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Fiscal Quarter
Impacts to Retail Businesses along Dexter Ave North
DEXTER
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SR 9
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Mer
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Am
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ove
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So
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Sales index is trending at a positive 5% annual growth rate
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Dexter Avenue
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Amazon
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Vibrant CompleteStreets
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Dexter onto Mercer
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Mercer toSeattle Center
Image: Seattle Bike Blog
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Mercer toSeattle Center
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Westlake
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Westlake
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Westlake
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Questions?
City Traffic Engineer
https://www.seattle.gov/visionzero