S Dearborn St Protected Bike Lanes

What's happening now?

The Seattle Department of Transportation (SDOT) has determined that the S Dearborn St Arterial Asphalt and Concrete (AAC) Project will not have a probable significant adverse impact on the environment. As a result, SDOT issued a Determination of Non-significance (DNS) on February 5, 2018. This decision was made after review of a completed environmental checklist. The DNS and checklist may be examined through the links below:

SEPA Determination of Non-significance
SEPA Checklist

The public is invited to provide comments on the DNS and checklist. Comments must be provided no later than 5:00 pm, February 19, 2018.

In addition, any interested person may appeal this DNS by submitting a Notice of Appeal and a filing fee to the Office of the Hearing Examiner no later than 5:00 PM on February 26, 2018.

Please see the DNS for more information on providing comments and submitting appeals.

Project Description

Protected bike lanes physically separate people riding bikes from people driving and are distinct from the sidewalk. These lanes are especially attractive to people who might be willing to bicycle but are concerned about safety.

The current bike lanes were in installed in 1974 and were some of the first ones in the city, which were considered state of the art. Over a period of 5 years (2009 – 2013) there were 175 collisions along S Dearborn St and 19 of them involved people biking, which accounts for almost 11%.

This project will help us achieve Seattle's Vision Zero goal to end traffic fatalities and serious injuries by adding a protected buffered zone between people biking and people driving. Once the protected bike lanes are installed, people biking will have a safer and more predictable path to ride on the road, away from people walking and driving, which will improve safety for everyone and reduce collisions throughout the corridor.

Upcoming Work: Map

Dearborn map

People driving west will access Dearborn Ave S via Hiawatha Pl S to S Charles St to Rainier Ave S. Read more about the partial median.

Final Design

Community outreach began in summer 2015 and concluded in October with informational sessions held in the Jackson Place neighborhood, where neighbors asked questions and learned about the project.

Existing cross section
Existing cross section - typical

Planned cross section
Planned cross section - typical

We'll use green pavement markings to emphasize safety at intersections and driveways where people biking and driving cross paths. In areas where the center turn lane is underused, we'll repurpose that space to provide wider widths for the protected bike lanes. At locations where there are higher volumes of left turn movements, the center turn lane will be maintained. These locations are:

  • Northbound 6th Ave S
  • Northbound 6th Ave S
  • Southbound Maynard Ave S
  • On-ramp to northbound I-5
  • Northbound Corwin Pl S

Updated intersection design
Updated intersection design at S Dearborn St and Rainier Ave S.

The intersection of S Dearborn St and Rainier Ave S, considered one of the busiest in the city, will undergo a series of improvements as part of the project. In order to accommodate the width of the new protected bike lanes and allow longer green cycles for everyone traveling through it, we are adding a partial median for westbound traffic on S Dearborn St at Rainier Ave S. This will decrease delays for people traveling through the intersection and reduce the number of people cutting through the Jackson Place neighborhood to access I-5.

Vehicle and people volumes
Current % of Vehicles and Total People Volumes approaching the intersection weekdays from 4 – 7 pm.
* Best practice assumption of 1.6 people per vehicle and transit ridership.

Recent Traffic studies at the intersection and Jackson Place neighborhood show how these improvements will make it easier and safer for people to clear the intersection in a timely manner, while improving reliability on bus routes along Rainier Ave S. Access to bicycle facilities downtown and along the nearby neighborhood greenway on Hiawatha Pl S will also be more convenient by the new intersection improvements.

Updated percentages
Delay reduction percentages for people using transit and driving after diverter implementation.

Route comparison
Route comparison before and after diverter implementation.

Diverter stats
Diverter will decrease overall delay at the intersection by approximately one minute when accessing the Jackson Place neighborhood.

Schedule and What You Need to Know About Upcoming Work

Work will occur in 2 phases:


The first phase of work includes installation of a buffered bike lane from 6th Ave S to just west of I-5 and from just east of I-5 to Rainier Ave S; new left turn signal at Charles St.; a partial median on S Dearborn St at Rainier Ave S that will restrict westbound access at Rainier Ave S for people driving.


The second phase paves the street from just east of I-5 to Rainier Ave S, improves pedestrian crossings, and upgrades the buffered bike lane with white plastic posts. This protected bike lane will run along S Dearborn St from 6th Ave S to Rainier Ave S (including under I-5). Notice of construction will be provided in advance.

Community Outreach

October 24 Drop-in Session #2
October 20 Drop-in Session #1
October 20 CID Preservation and Development Authority Mtg
October 13 Jackson Place Community Council
October 11 Bing Kung Association
September 29 Chong Wa Benevolent Association
September 19 Gee How Oak Tin Apartments
September 3 Bush Hotel
August 27 Nihonmachi Terrace Apartments
August 26 Demingo Apartments
August 25 Little Saigon Public Safety Meeting
August 19 Eastern Hotel Tenants
July 6 12th Avenue Iron
July 1 Bicycle Advisory Board
June 24 Goodwill Industries
June 16 Freight Advisory Board
June 10 King County Metro


This project is funded by the 9-year Levy to Move Seattle, approved by voters in 2015.


S Dearborn St Safety Improvement Project Mailer (May 2017)

S Dearborn St Protected Bike Lane Project Drop-in Sessions Postcard

Fact Sheet (English)
Fact Sheet (Vietnamese)
Fact Sheet (Chinese)

Postcard (English)
Postcard (Vietnamese)
Postcard (Chinese)

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