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Seattle plan would reduce default speed limits across the city

Dr. Beth Ebel from Harborview speaks in support of lower speed limits, citing her experience with young traffic trauma patients.
Dr. Beth Ebel from Harborview speaks in support of lower speed limits, citing her experience with young traffic trauma patients.

In a busy city like Seattle, a higher speed limit does little to speed up your trip because traffic and stop lights will prevent you from getting up to top speed very often. But speeds have a huge impact on whether someone is seriously injured or killed in a collision and whether collisions happen at all.

That’s why SDOT’s announcement today, flanked by Councilmembers Mike O’Brien and Tim Burgess, is so smart: Reduce the default speed limits on busy “arterial” streets to 25 miles per hour and on “non-arterial” mostly residential streets to 20 miles per hour.

The change will not affect major streets that have their own signed speeds, such as Aurora. It will only affect those streets where there are no speed limit signs. So knowledge of the change will require a significant public education effort. They will also need to change about 500 signs, mostly at the city limits, to display the new default speeds.

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Councilmember Burgess called the change “the next step to achieving Vision Zero,” the city’s goal of eliminating serious injuries and deaths in traffic by 2030.

“This change would mainly impact the off-peak hours when there are more high-end speeders and more severe collisions,” notes a press release.


In fact, SDOT quietly retimed downtown traffic signals over the winter and spring to 25 miles per hour. This means that someone going 25 on certain streets will hit green lights, but someone going faster will have to hit the brakes at every stop light.

“What we saw is that traffic started moving more reliably and more safely,” said Kubly of the signal retiming project. And that makes a lot of sense when you think about how downtown actually functions.

Put yourself behind the wheel on a typical day on, say, 5th Ave. The street is rarely wide open with no traffic, so a higher speed limit doesn’t help you at all. You just crawl along at the speed of the vehicle in front of you. But in those few blocks where the road does open up, you hit the gas and get up to 35 or 40 before slamming on the brakes at a red light. You’ve cut effectively no time from your trip, but for that block or two your car was an outsized (and perfectly practically legal) risk to all the people driving, walking and biking in this dense area. At 40 miles per hour, someone hit will very likely die. At 25 miles per hour, someone hit will likely live. But more importantly, at 25 you are much more able to avoid collisions from happening at all.

In other words, there are two ways of measuring speed. A: The time it takes to get from one place to another (average speed) and B: The highest mark your speedometer reaches during your trip (top speed). This rule change will hardly affect A at all, but it could significantly reduce B. That’s a smart change.

The speed limit change will go before the City Council’s Transportation Committee September 20 before heading to the full Council for a vote “later this month,” according to the release. If it passes, the changes could start rolling out in November.

There will be a warning period right after the changes take effect before police start giving out citations (Is more enforcement a good idea? More on this in a follow-up post).

“Most people actually want to go the speed limit,” said SDOT Director Scott Kubly. So the biggest immediate benefit from this change will likely come from more people simply knowing about the speed limit changes.

The lower speed limits will also make it easier for the city to implement traffic calming improvements on more streets where speeding remains a problem.

Shout out to all the safe streets advocates, especially Gordon Padelford at Seattle Neighborhood Greenways, for the hard work to help build political support for this effort.

Here’s the full press release:

Mayor Ed Murray and Councilmembers Tim Burgess and Mike O’Brien today unveiled a proposal to enhance safety on Seattle’s streets by changing the speed limit on all residential streets from 25 to 20 MPH and streets in the center city from 30 to 25 MPH. The proposal is part of Seattle’s Vision Zero plan to end traffic deaths and serious injuries on city streets by 2030.

“Having helped pass the Neighborhood Safe Streets Bill during my time in the legislature, I’m proud that Seattle will be the first city in the state of Washington to implement lower speeds on all residential streets,” said Mayor Ed Murray. “When combined with other elements of our ongoing Vision Zero work, such as redesigned roadways and data driven enforcement, lower speed limits will help make Seattle’s roads safer for all.”

Speed contributes to 25 percent of collisions citywide and 42 percent of downtown traffic fatalities every year. It is the critical factor in survivability for a crash. Pedestrians struck by vehicles traveling at 25 MPH are half as likely to die as those struck at 30 MPH.

“Studies show that lowering speed limits is one of the best ways to improve safety in our neighborhoods,” said Councilmember Tim Burgess. “Reducing speeds will not only reduce accidents and fatalities but it also brings peace of mind for those who use our sidewalks, including children and our elderly neighbors. The reduction we are proposing will not restrict mobility.”

In residential areas, going down to 20 MPH brings the entire neighborhood to existing school zone speed limits, making safer routes of travel for all. Vehicle safety in Seattle has improved significantly, but not for people walking and biking. Pedestrian and bicycle collisions make up seven percent of total crashes, but nearly half of fatalities. The new speed limit will apply to 2,400 miles of non-arterial streets and help enhance safe routes to schools, transit, parks and other destinations.

“The proposal presents the opportunity that exists to balance the need for safe passage with thoughtful engineering,” said Councilmember Mike O’Brien. “Reducing speed limits has a direct impact on safety and helps the City implement better design standards that will allow drivers, bikers, pedestrians and parents alike to breathe a little easier as we head back to school by bus, bike or single passenger vehicle.”

Downtown there has been a 20 percent increase in speed-related fatal collisions over the last four years. Signal timing has already been adjusted to the new 25 MPH speed limit and drivers are moving more efficiently through the center city. A 25 MPH speed limit fits the typical operating speed of vehicles in the downtown core today.

This change would mainly impact the off-peak hours when there are more high-end speeders and more severe collisions.

“Speed is the critical factor in crashes, and lowering speeds is essential if we want to end traffic deaths and serious injuries on our streets,” said Seattle Department of Transportation Director Scott Kubly. “You can save a life for only an extra minute more per trip.”

This speed limit is consistent with the Washington State speed limit for city streets and Seattle is the only city in King County with an arterial speed limit over 25 MPH. Also, 25 MPH is the speed limit in the overwhelming majority of city centers nationwide including cities like New York, Portland, Phoenix, Denver and Houston.

The City Council’s Sustainability and Transportation Committee will discuss and vote on the proposal at its September 20 meeting. The legislation will then go before the full council for a vote later this month. If passed into law, the City expects to begin rolling out speed limit changes in November.

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29 responses to “Seattle plan would reduce default speed limits across the city”

  1. William C.

    So, what’re the implications of this for Link on MLK, which is currently constrained to the speed limit of the cars around it? Given how it’s already been criticized for its slowness, I think it’s very important not to slow it down even more and drive more people to their cars.

    1. Gary Yngve

      Why cannot they decouple Link right of wardroom car right of way? All way stop while Link going through.

      1. Gary Yngve

        Stupid phone. Wardroom -> way from

      2. William C.

        I seem to remember hearing online that the FRA requires actual crossing gates if the train’s moving faster than cars. If that’s actually the case (I’m not sure), we’d need to put actual crossing gates at every intersection along MLK – which would also solve the problem of left turner – train collisions. It’d be interesting to get a cost figure on that.

        Alternatively, we could keep MLK as a unique exception with a higher speed limit. That might be problematic given people crossing the street to get to stations in the median, though.

      3. Skylar

        MLK doesn’t have crossing gates because neighborhood groups thought that they would impact character:


        It looks like there’s been research in operating LRT at over 35mph without gates though:


        I don’t have a login so I can’t read it though.

    2. Tom Fucoloro

      MLK is signed 35, so it’s not impacted by the default limit. Can/should the city change the speed limit on the greet while still allowing for efficient Link travel? Of course! But that would probably be separate from this change.

  2. Gary Yngve

    As a pedestrian, so glad the city is doing this! As a fast and fearless Fred, I look forward to framing my first speeding ticket.

  3. Davepar

    Glad to hear about this change. 25 mph seems too fast for most residential streets. Especially considering that Seattle police don’t ticket for <5 over the limit.

    I noticed the change in light timing on 4th Ave. Used to be it was very difficult to keep up with the lights if there was any traffic at all. Much easier now.

  4. (Another) Tom

    Awesome news!

    I emailed my councilmember this morning to express my support and received a warm reply; feels good to know my opinion was counted.

    “The speed limit change will go before the City Council’s Transportation Committee September 20 before heading to the full Council for a vote “later this month,” according to the release. If it passes, the changes could start rolling out in November.”

    I encourage you to email your representative too. Let them know this legislation is important to you.

    1. Andres Salomon

      Yes. And we should probably show up on the 20th at Council and speak in support of the lowered speed limits during public comment.

  5. ODB

    The title of the post–“Seattle will reduce default speed limits across the city”–is not accurate. It is a proposal at this stage. Therefore, it is inaccurate to say that Seattle “will” implement it.

    Also, I don’t think it’s “perfectly legal” to exceed the speed limit for a few blocks. Am I missing something here? Or is this a rather glaring misstatement of the traffic law that is the subject of this post?

    1. Tom Fucoloro

      You’re right. That was a bit sloppy. I said “will” because the Council, SDOT and Mayor’s Office presented it together, suggesting there is broad support from all necessary parties. But you’re right, never count your chickens, etc. I changed the headline.

      And the “perfectly legal” part was sloppy. I changed it to “practically” to acknowledge that nobody gets pulled over for doing 5 or so over the limit, making that the de facto limit. But yeah, “perfectly” is not correct.

  6. William

    This is a great idea if it works but since the SPD seems incapable of enforcing the current speed limits on anything more than an occasional basis, I am not sure how much effect it is really going have.

    The lights in parts of downtown are quite well timed but in much of the rest of Seattle they are not. This encourages speeding and red light running and of course there is very little police enforcement and no one wants traffic cameras, so this style of driving has now become the norm.

    1. William

      Drove up and down 35th Ave NE and this morning and to stay in the stream of traffic I have to drive at nearly 40 mph. I do not think there is speed enforcement down this road more than a handful of times per year and this is probably a pretty typical arterial. So I really question whether a new speed limit going to have much effect unless there is a radically new plan for enforcement.

    2. Gary Yngve

      I want traffic cameras! It’s become socially acceptable for car drivers to speed, run right-on-reds, not stop for peds in crosswalk, text while driving… SPD needs to enforce the rules of the road however they can.

      1. Geoff

        I agree. I can’t believe how may times I am passed (even in a school zone) on 35th Ave NE.

  7. Jack Nolan

    More rules they won’t enforce. That “no cell phone while driving” rule sure is making a difference- NOT.

    Humans are stupid. This won’t help.

  8. Law Abider

    More smoke and mirrors from SDOT so they can pat themselves on the back as they steam forward towards their Zero Vision. Meanwhile, pedestrians, cyclists and car passengers will continue to get injured and die.

  9. Bob Hall

    I hate to join the crowd raining on your parade, but I need some evidence from SDOT and/or this blog that shows that speed limits affect the behavior of people driving.

    I found this to be pretty informative:

    “Moreover, the one test of a lower speed limit on a bike route in Minneapolis produced negligible change in traffic speeds, according to city measurements. Tests in 2012 and 2013 involved a 25 mph limit on 15th Avenue SE. near the University of Minnesota.

    ‘It basically tells me that a sign doesn’t change behavior,’ said Jon Wertjes, the city’s director of traffic and parking services.”

    I’m all for a 20mph speed limit but I don’t expect it to change things.

    1. Josh

      Nothing overnight, of course, but long-term, setting a 20 mph speed limit allows engineers to design residential streets for 20 mph.

      Street design is the primary influence on driver speed, and higher speed limits effectively prohibit many forms of traffic calming that get drivers to maintain safer speeds without Draconian enforcement.

      Allow the engineers to design for 20 mph and you can get shorter pedestrian crossing distances, tighter corner radii, raised crosswalks and speed humps engineered for 20 mph — many of the bicycle- and pedestrian-friendly features currently limited to Neighborhood Greenways could become default treatments if engineers are allowed to design for 20 mph.

      1. Molly

        yes, this exactly. Right now we can’t (legally) fix the streets to force safe driving. After the change we can.

  10. J

    How about installing sidewalks in very busy residential areas, like North Greenwood? More short sighted selective “fixes” from a stupid city.

  11. Andres Salomon

    To all the people saying that just changing signs won’t work: you’re right. This is just the first step.

    Did you ever try to get speed humps or traffic circles installed on your street? Generally what happens is you’ll do a speed study, and SDOT will tell you that the 85th percentile driver speed is only 27mph, while the official speed limit is 25mph; so there’s nothing they can do. Or on an arterial, drivers are only slightly speeding so traffic calming won’t be done.

    This is exactly what happened on NE 55th, for example, after a hit-and-run. The city conducted a speed study: http://www.ravennabryant.org/2014/01/city-to-conduct-study-of-ne-55th-street/
    The study results showed that people were driving at 31-32mph, while the posted limit was 30mph:
    So because people were mostly obeying the speed limit, they did nothing; despite the fact that the speed limit itself was too high. Now, if the speed limit was 25mph, then that study would’ve shown that the vast majority of people were going 6-7mph over the speed limit. That would’ve been cause for traffic calming measures to be put into place. But with a default speed limit of 30mph; *shrug*, nothing to be done.

    That’s why this change is so huge. We’re changing the baseline expectations for speed through our streets. No, it’s not going to be immediately effective, but it will allow us make changes to dangerous streets where we currently can not.

    1. William

      I guess so but this will only lead to incredibly incremental and slow improvements in road safety. Given that road deaths per vehicle mile in the US are about 2x those in, for example, the UK, a disparity that become even larger when adjusted for differences in the mix and relative risks of different types of roads (freeways, rural two lane, urban etc), it seems like we need something a little more transformational, if you want to describe it as “huge”.

    2. Neel Blair

      This. We’ve tried on my street many times on my street. We’re on a route that makes it sometimes advantageous to cut through and avoid an intersection. People do it fast, all the time, and we have tons of kids on our street.

      People speed on our block, and rather consistently, but not ENOUGH. Because that’s the bar we’re given by the city.

      A lower limit changes the bar.

      1. William

        As an alternative, the Mayor and Council could just change the rules governing the SDOT threshold for speeding to be “ENOUGH”. Why the heck not a revenue neutral approach (i.e. fines that are high enough to pay for enforcement) to vigorously enforce the speed limits (not 5-10 mph above it) that we actually have. It is perverse that in order to get people to drive sensibly we have to add speed bumps and chicanes on every street. If the new lower speed limits suddenly make lots of street eligible for new infrastructure as I am sure they will, then you can bet there will then be a huge backlog and funding shortage to do the studies and implement the solutions. In my neighborhood way less than half the residential intersections have rotaries and that is not because of a lack of desire in the neighborhood but that because that is all the city has been able to afford over 20 odd years. So we can wait another 30 years to get them on all intersections (if the program is even still active) or alternatively the city could enforce the old or better still the new speed limits starting tomorrow.

  12. […] DOT Director Scott Kubly and council members Mike O’Brien and Tim Burgess announced the proposal yesterday. The new rules need to be approved by the City […]

  13. Curi

    Let me first say that I’m very happy that posted speed limits are likely to be lowered on many Seattle streets. That said, since the speed limits of neighborhood and arterial streets can’t be enforced to a degree high enough needed for actual behavior change, I think this is mostly a feel-good effort rather than anything more substantive. Without legitimate fear of receiving a traffic ticket, I believe drivers generally drive as quickly as their comfort level allows. So… They probably won’t drive any slower on residential and arterial streets than they currently do. I’m of the opinion that the only way to truly impact driving behavior in this scenario is to implement various forms of traffic calming. This could be in the form of speed bumps & humps, medians, lane and striping alterations, etc.

  14. […] change itself is pretty simple, but the implications for safety could be huge as we reported when it was announced. All it really does is change a bunch of signs near the city limits to spell out the new default […]

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