20 MPH Zones

Designing Safer Streets

20 MPHThe goal of the 20 MPH Zone program is to improve safety and livability in Seattle neighborhoods by decreasing vehicle speeds. SDOT hopes that reducing neighborhood speed from 25 MPH to 20 MPH will make streets safer for all travelers. There are two phases to our neighborhood 20 MPH Zone program:

  • Phase One: Install 20 MPH signs and 20 MPH markings on the street.
  • Phase Two: If speeds are not reduced with signs, install other safety improvements such as curb bulbs, speed humps, and other appropriate traffic calming devices.

Neighborhoods in cities all over the world are developing "Slow Zones." That's why we want to try out this program in Seattle.

  • · London had a 46% collision reduction in their Slow Zones.
  • · New York Slow Zones report slower and less aggressive driving.

Seattle's 20 MPH Zones are part of a safety-based Vision Zero program that is a partnership between the Seattle Department of Transportation (SDOT) and the Seattle Police Department (SPD) to end fatalities and serious injuries on city streets by 2030.

20 MPH Zone Program