Traffic Calming

In 2015, Seattle Department of Transportation (SDOT) piloted 20 MPH Zones in five areas City-wide. As part of that pilot program, we did 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.

SDOT focuses limited traffic calming dollars on streets where speeds are highest and this is on streets where there are no curbs. Because there are many neighborhoods without curbs, other considerations for prioritization are streets near schools, parks, or other pedestrian generators.

If you are interested in traffic calming, the first step involves creating a common understanding with your neighbors and the City of the existing problems on your street. Once a common understanding is reached, the appropriate funding source also becomes apparent. The first step to reaching a common understanding generally involves borrowing a radar gun to record speeds on your street for two hours.

Borrowing a Radar Gun

Speed WatchTo borrow a radar gun, contact your nearest Customer Service Centers. When you go in to pick up the radar gun, you will receive instruction on its use. Please note that you may only borrow the radar gun for three days so you want to plan to pick up the gun and then use it the next day.

You will receive several forms when you pick up the radar gun including directions and a recording sheet.

Most people who borrow the radar gun find that there is not a speeding problem on their street. SDOT defines a speeding problem as 15% or more of the traffic is going five miles over the speed limit. If you find that your street has these results after borrowing the radar speed gun, then SDOT will order a traffic study for the street and work with you to identify an appropriate funding source and appropriate traffic calming device from the Engineering Toolkit.