AUGUST 2020 | FHWA-SA-20-033 

VISION ZERO SUCCESS STORY – INFRASTRUCTURE

Rainier Avenue South Redesign — 

Seattle, Washington

Background 

The Rainier Valley neighborhood located in 

southeast Seattle is home to one of the City’s 

most culture-rich and diverse populations. Rainier 

Avenue South is a principal arterial street that 

connects residents and communities along the 

former regional rail corridor. The area surrounding 

Rainier Avenue South includes many land uses like 

retail, schools, and parks. These uses are pertinent 

to pedestrians, cyclists, transit users, and drivers. 

It was also the corridor with the highest number 

of traffic crashes in Seattle; the corridor had a per 

mile crash rate that is greater than other streets in 

the City that carry more than twice the volume of 

traffic as on Rainier Ave South. The City launched 

Vision Zero1 efforts in 2014, one of which was 

working with the community to redesign a onemile segment of the eight-mile corridor for the 

pilot phase of the Rainier Avenue South Corridor 

Safety Project. The City implemented changes to 

the piloted segment between South Alaska Street 

and South Kenny Street over a weekend in August 

2015. 

Rainier Avenue South carries over 13,000 people 

daily on transit, is a freight and emergency 

response route, and serves between 19,700 and 

26,600 vehicles each weekday. Studies in the 

corridor show that between 1,000 and 2,000 

vehicles per day travel along the corridor at a 

speed greater than 10 miles above the 30 miles 

per hour (mph) posted speed limit. The total 

average number of annual crashes over the 

10 years prior to the redesign was 95 crashes, 

9 serious injury crashes, and 1 fatality crash. 

Key Successes

The redesign of the Rainier Avenue South 

corridor including geometric changes, signal 

timing and speed limit modifications, and 

transit efficiency measures such as new bus 

lanes (figure 1) resulted in the following traffic 

safety successes: 

15% -overall decrease in the

total number of crashes.

30% -overall decrease in total

injury crashes.

28% and 52% (southbound and

northbound, respectively) -decrease in the 

number of speeders recorded at South 42nd 

Street.

Figure 1. Photograph. Newly installed bus lane on 

Rainier Avenue South at South Cloverdale Street. © 2020 Seattle DOT

1 Seattle Department of Transportation. (2020). “Vision Zero”. 

https://www.seattle.gov/visionzero
Additionally, of the over 70,000 people living in 

the surrounding zip codes, 15 percent of homes 

do not own a vehicle; making pedestrian safety a 

top interest of the community. 

Implementation

The City made the following design changes to 

improve safety along the one-mile pilot segment:

• Reconfigured Roadway – Removed one travel 

lane from each direction (shown in both figures 

2 and 3) to accommodate a center two-way 

left-turn lane. 

• Prioritized Transit – Added a transit priority 

signal2 and added dedicated bus (and rightturn) lanes to both directions.

• Retimed Signals – Retimed signals for the new 

flow of traffic, including longer cycle lengths, 

leading pedestrian intervals3, and left-turn 

signals.

• Lowered Posted Speed Limit – Reduced the 

posted speed limit from 30 to 25 mph.

• Enhanced Sight Lines – Added pavement 

paint and flexible delineator posts at crossings 

to improve sight lines for traffic entering the 

corridor and reduce distance for pedestrians 

crossing the street. Additionally, new reflectors, 

curb bulbs, and raised and/or repainted 

crosswalks increased visibility for pedestrian 

crossing.

Outcomes 

The corridor improvements implemented during 

the pilot consisted of a reduction in high speeding 

(40+ mph), improved pedestrian crossings, and 

modified turning movements. This resulted in a 

15-percent reduction for all crashes, a 30-percent 

reduction in injury crashes, and a 40-percent 

reduction in bicycle and pedestrian crashes. The 

City anticipated travel time for general traffic along 

this study corridor to increase and it did so by 

about 54 and 81 seconds in either direction. The 

City also expected and observed some diversion 

in volume from Rainier Avenue South, as traffic 

rerouted to the nearby, and under capacity Martin 

Luther King Jr Way South. 

The addition of bus lanes and transit priority signals 

helped to maintain or improve transit services, 

with the northbound travel time reducing by three 

minutes during the PM peak hour. The southbound 

route experienced no significant change during 

the same time period.

Funding

This project was funded by the City’s Bridging the 

Gap safety program. 

Figure 2. Graphic. Aerial photograph of Rainier Avenue South intersection showing transit and lane improvements.

Figure 3. Graphic. Aerial photograph of Rainier Avenue South intersection showing rechannelization improvements.© 2017 Seattle DOT

POINT OF CONTACT

DONGHO CHANG

CITY TRAFFIC ENGINEER 

SEATTLE DEPARTMENT OF TRANSPORTATION

206.684.5106 | DONGHO.CHANG@SEATTLE.GOV

JIM CURTIN 

PROJECT DEVELOPMENT DIVISION DIRECTOR 

SEATTLE DEPARTMENT OF TRANSPORTATION

206.684.8874 | JIM.CURTIN@SEATTLE.GOV

2 Federal Highway Administration. (2015). “Signal Priority.” 

 https://www.transit.dot.gov/research-innovation/signal- 

 priority

3 Federal Highway Administration. (2017). “Leading Pedestrian Intervals.” https://safety.fhwa.dot.gov/provencountermeasures/lead_ped_int/

Rainier Avenue South Project Website: https://

www.seattle.gov/visionzero/projects/rainier-ave-s