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

6

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

Date (xx/xx/xxxx) Department Name Page NumberSeattle Department of Transportation 9

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

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Impacts to Retail Businesses along Dexter Ave North

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Sales index is trending at a positive 5% annual growth rate

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Dexter Avenue

Date (xx/xx/xxxx) Department Name Page NumberSeattle Department of Transportation 37

Amazon

Date (xx/xx/xxxx) Department Name Page NumberSeattle Department of Transportation 38

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?

Dongho.Chang@seattle.gov

City Traffic Engineer

https://www.seattle.gov/visionzero