Speed humps

Speed humps, cushions, and tables discourage drivers from speeding. Speed humps are raised asphalt bumps that extend across the street. Speed cushions resemble speed humps with added wheel cutouts to allow large vehicles, like buses or emergency vehicles, to pass through unaffected. These two devices are typically spaced 300-400 feet along the street. Speed tables are 12-22-foot long, flat-topped speed humps that are typically used on fire department routes.

Street characteristics, such as width, determine the type of device we use. We usually install speed humps on non-arterial or residential streets, and reserve speed cushions and speed tables for busier streets with larger vehicles. 

How does SDOT decide where to install speed humps, cushions, or tables?

  • SDOT installs speed humps and speed cushions on neighborhood greenways and streets around schools.
  • If a street is too steep (i.e. the grade is more than 7%), then SDOT does not install speed humps due to drainage issues.

How can the community request speed humps?

  • The community may pursue funding through Your Voice Your Choice or Neighborhood Matching Fund.
  •  If the community applies through these programs, SDOT conducts a traffic study to verify that 15% of the vehicles are traveling at more than five miles per hour over the speed limit.

How much do they cost?

Speed humps and cushions are about $5,000. Speed tables cost about $10,000.

How long do they take to install?

1-2 years. We usually identify priority streets with high speeds in the first year, and construction happens the next year.

For additional information, see page 19 in the Safe Routes to School Engineering Toolkit. 


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

Newsletter Updates


Sign up for the latest updates from Transportation

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.