20-25 MPH or Safe Speeds For Seattle
Frequently Asked Questions
Who supports the 20/25 MPH idea?
Many community, public health, school, business, and advocacy groups are asking for safer speed limits. We hope you will too after learning more about how this idea will save lives!
What’s the idea for non arterial streets (neighborhood streets)?
A safe and livable 20 MPH speed limit for every neighborhood street in Seattle. Currently, the “default” speed on non-arterial streets is 25 MPH - faster than you probably drive on neighborhood streets. 20 MPH streets will be safer for us all, particularly people walking and kids playing.
What’s the idea for arterial streets?
Streets that are known to be dangerous should have speed limits examined, and potentially reduced to 25 MPH, as part of a comprehensive safety strategy. Additionally Communities should be able to request the city work with them to reduce arterial speed limits especially in areas such as business districts and through community hubs. Traffic should be smooth and safe and people should be able to get where they need to go reliably and safely. One part of this would be to change the "default arterial speed limit" signs at the entrances of Seattle to 25 MPH to let visitors know that they may encounter 25 MPH arterial streets.
Will changing the speed limit save lives?
Yes. Changing the speed limit will make our streets safer for everyone! Each year in Seattle about 20 people are killed in traffic collisions and another 150 are seriously injured. 42% of of these collisions involved speeding. Driving even a little slower gives us all more time to see each other and makes it easier to stop. Well-established research shows that even a small speed decrease makes a big difference. Vehicle stopping distance improves by 45 feet (23%) when traveling at 25 MPH versus 30 MPH. If a collision does happen, nine out of ten people hit by a driver going 20 MPH will survive, while at 30 MPH survival rates decrease to only five out of ten.
Will 20 MPH for neighborhood streets mean I’ll take longer to drive anywhere?
No. On non-arterial (neighborhood) streets, it is already difficult to drive faster than 20 MPH due to roundabouts and narrow street widths. When people do speed it is especially dangerous for elders and children living and playing in their neighborhoods.
Would a 25 MPH for arterial street make my commute longer?
First of all, this proposal does not change all arterial streets to 25 MPH (see FAQ above). Not likely. Most people drive during rush hour, when it’s already difficult to drive fast. Travel time is primarily determined by factors like traffic signals, congestion, and turning vehicles. Moreover, a top reason for congestion in Seattle is traffic collisions. Reducing speeds will reduce collisions and reduce the frequency of collision-related congestion. People driving outside of peak travel times may see a slight increase in their travel time. If you’re going 30 MPH without any interruptions, a lowered speed limit of 25 MPH will add about 1 minute to your trip (the average car trip in Seattle is about 3.5 miles). We think the occasional extra minute is worth it to save someone’s life.
When would the speed limits change, and which streets would be affected?
A default 20 MPH speed limit for non-arterial neighborhood streets could take effect as soon as the signs could be changed, except where they are currently signed to 15 MPH (as they are in some school zones).
The 25 MPH limit for arterial streets would be implemented on a case by case basis over time with community and SDOT evaluation (this is the model used by every other city in King County). Only then would speed limit signs be changed and a 25 MPH limit enforced.
Are there other cities with 20/25 MPH speed limits?
Yes. 20 MPH neighborhood streets are widely seen as a best practice around the world to keep neighborhoods safe and comfortable places to live in and raise families. Every other city in King County has a default speed limit of 25 MPH or lower. Many other large cities around the world, including New York, Los Angeles, Washington D.C., London, Paris, Berlin, and Tokyo, already have a speed limit set to 25 MPH or lower to improve drivers’ ability to avoid crashes.
Isn’t 20/25 MPH just a way to raise additional revenue for the City?
Not at all. Seattle should reduce its speed limit in order to make the city safer for people walking, biking, and driving. A lower speed limit helps meet the City’s goal of bringing traffic fatalities to zero. Data shows that driving at or below 25 MPH improves drivers’ ability to avoid crashes.
Sometimes streets are just dangerous. Why focus on speed?
Dangerous driver choices, such as speeding, failure to yield, and improper turns, are the primary cause or a contributing factor in 70% of pedestrian fatalities. Legislative efforts, such as lowering the speed limit, combined with engineering street safety improvements, education and enforcement work together to create safer streets for us all.
What is Vision Zero?
Seattle’s goal for traffic fatalities and serious injuries is the same you would want for you and your family: zero (this goal is called Vision Zero). While zero fatalities may seem ambitious, it’s the same standard we expect of our airline system. 20/25 MPH is a great way to improve drivers’ ability to avoid crashes!