Speed Limits

Updated: April 2021

What’s happening now?

SDOT workers install a new 25 mph speed limit sign
We are reducing and posting 25 MPH speed limits on just about every arterial street (any street with a yellow dividing line) in Seattle.

Some arterial streets with higher traffic volumes will have their posted speed limit reduced to 30-35 MPH with ongoing evaluations for a lower speed limit.

Overview

Speed is the critical factor in the frequency and severity of crashes.

As we continue to redesign our high injury network of streets, we’re also looking at proactive, systemwide improvements. Lowering speed limits across the city is a key element of this work.

“Addressing dangerous speeding is the only way for everyone to get around safely. As we design a transportation network that serves everyone, we have to prioritize saving lives as we manage our streets.”

SDOT Director Sam Zimbabwe

Since Seattle adopted Vision Zero in 2015, we've made big strides lowering speed limits across the city, prioritizing the safety of people over the throughput and speed of vehicles. Seattle is one of the first cities in the country to study how reducing speed limits and increasing speed limit sign frequency improves safety for everyone. Early results show a decrease in vehicular speeds and a reduction of up to 39% in crashes.

Comparison of a driver's field of vision at 15 mph and at 30 mph. The 15mph driver can see the road as well as pedestrians off to the sides, the 30 to 40 mph driver can only see a narrow portion of the road.

A driver's field of vision increases as speed decreases.  At lower speeds, drivers can see more of their surroundings and have more time to see and react to potential hazards.

In early 2020, we started our work with posting speed limit signs on every arterial street in the city and we completed this work in early 2021. People will see more speed limit signs (we're putting them in every quarter mile) to increase awareness. 

Check out the Speed Limits map below to see our progress so far.

Why?

Lowering vehicular speeds has been and will continue to be a key part of Seattle's Vision Zero efforts.

We'll say it again: speed is the critical factor in the frequency and severity of crashes. A few miles per hour difference can make a big impact on a person's chance of survival. 

This image details survival rates of pedestrians if hit by vehicles traveling at different speeds. 9 out of 10 pedestrians survive if hit by a vehicle traveling at 20 miles per hour. 5 out of 10 pedestrians survive if hit by a vehicle traveling at 30 miles per hour. Only 1 out of 10 pedestrians survive if hit by a vehicle traveling at 40 miles per hour.

Race and social justice

We're seeing that speed limit signs alone can improve public safety, even without changes in enforcement or urban design.

This finding is important because enforcement disproportionately impacts Black people and other people of color. At SDOT, we are learning and listening to how our urban spaces disproportionately place Black people in harm's way. In addition, speed limit signs are the most cost-effective method of reducing speed, and lead to promising results for safety.

What We've Done So Far

Our early work with reducing speed limits started with redesigning high injury streets - places that have had high frequency of crashes due to vehicular speeds and activity from those who walk and roll throughout the corridor. We'll continue redesigning streets and making proactive, systemwide changes.

In 2016, we changed the Seattle Municipal Code to reduce citywide default speed limits. The default speed limit for non-arterial streets changed from 25 MPH to 20 MPH. The default speed limit for arterial streets changed from 30 MPH to 25 MPHunless otherwise posted. At that time, we installed new signs at highway off-ramps, ferry terminals, and at the arterial city limits, and reduced downtown speed limits to 25 MPH.

In 2017, we focused our speed limit efforts on urban villages (think: neighborhood business districts). These are where we see the most activity (lots of people walking, biking, driving, and taking transit) and the most crashes involving pedestrians - nearly 80% of pedestrian collisions occur within or near urban villages.

In 2020, we moved forward with reducing speed limits to 25 MPH for most arterial streets across the city, with some arterial streets posted 30-35 MPH.

In 2021, we reduced speed limits on several WSDOT arterials and will continue working closely with WSDOT on evaluating lower speed limits on the state arterials that go through the city.

Click the image below to enlarge the timeline of speed limit changes

A timeline illustrating the speed limit changes shared in text above

Funding

This work is funded by the Levy to Move Seattle, a 9-year $930 million levy approved by voters in 2015.

City of Seattle Speed Limit Map

The map below reflects current speed limits and upcoming speed limit work we've issued to city crews.

Click on a street to see what the speed limit is.