Traffic Calming

Seattle has been calming traffic since 1978. Since then the Seattle Department of Transportation (SDOT), in partnership with residents, has been involved in the installation of thousands of traffic circles, speed humps and other traffic calming devices. The purpose of these traffic calming devices has been to reduce collisions and speeds on neighborhood streets, thereby creating safer and more pleasant neighborhoods. 

In 2015, SDOT piloted 20 mph zones in five areas City-wide. As part of that pilot program, we completed numerous traffic studies. We found that most people traveled under the speed limit when the street is 25 feet wide and there is parking on both sides of the street. As a result, we are focusing our limited traffic calming dollars on streets where speeds are highest, and this is typically on streets where there are no curbs. As there are many neighborhoods without curbs, other considerations in our prioritization include streets near schools, parks, or other pedestrian generators.

If you are interested in traffic calming solutions for your neighborhood, consider the options we've summarized below. You might want to think about applying to the Your Voice Your Choice (YVYC) program or Neighborhood Matching Fund (NMF) program to fund these solutions. 

  • Yard Signs: Yard signs are intended to inform drivers that they are travelling on a neighborhood street and remind drivers to slow down. 
  • Parking Management: Parking on both sides of the street can be an effective traffic calming tool. On wide open streets, some drivers can feel comfortable traveling at higher speeds.  Narrower streets encourage drivers to slow down.  
  • Radar Speed Sign: The speed signs detect and display the speed of oncoming vehicles.  The displayed speed reminds drivers to drive responsibly.
  • Traffic Circles: Traffic circles guide vehicles through an intersection around a central island, forcing vehicles to slow down. These slower speeds help reduce the number and severity of collisions.  Landscaping in and around the traffic circle further improves neighborhood livability.

Home Zone Program

If you have concerns beyond speeding on your street, including cut-through traffic, you and your neighbors may want to look into other solutions in the Home Zone Program. 


Greg Spotts, Director
Address: 700 5th Ave, Suite 3800, Seattle, WA, 98104
Mailing Address: PO Box 34996, Seattle, WA, 98124-4996
Phone: (206) 684-7623

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The Seattle Department of Transportation (SDOT) is on a mission to deliver a transportation system that provides safe and affordable access to places and opportunities for everyone as we work to achieve our vision of Seattle as a thriving, equitable community powered by dependable transportation.