Traffic Data & Speed Limits


Public Works collects information on vehicle counts, travel speeds, and crashes in order to develop transportation projects that improve the safety and efficiency of our transportation system. Monitors traffic and related issues to enhance the safety and operation of our county roadway system. Learn more by visiting the Washington Department of Transportation (WSDOT) website and the Maps and Data statewide information page.

Speed Limits

Jefferson County Code (JCC) 10.05.040 addresses speed limits on county roads. Pursuant to state law at RCW 46.61.400, the default speed limit on county roads is 50 miles per hour (mph). RCW 46.61.415 provides that local authorities may determine and declare a different maximum speed on the basis of an engineering and traffic investigation and a conclusion that the alternate speed is reasonable and safe under the specific road conditions.

Exhibit A of Jefferson County Ordinance 11-98 (amended through Ordinance 6-01) identifies specific speed limits on county roads. Amendments to Exhibit A are adopted by resolution of the Board of County Commissioners after review of an engineering and traffic investigation, public notification and a public hearing. For more information view JCC 10.05.040(3).

Speed Limit Revisions

On September 27, 2010, the Board of County Commissioners adopted an updated Exhibit A, resulting in adjustments to the speed limit on select county roadways. Speed Limit Map.

Speed Limit Revisions - Engineer's Report

Public Works prepares an Engineer's Report in conjunction with proposed changes to speed limits. The Report typically contains a description and analysis of the following elements:
  • 85th percentile speed - 85 out of 100 drivers are traveling at this speed or less
  • Crash history
  • Roadside development
  • Roadway characteristics
  • Safe speed on curves
  • Speed limit recommendation
  • Traffic counts
The following links are a starting point for understanding how speed limits are typically established in Washington state and nationwide:

Neighborhood Electric Vehicles (NEVs)

Neighborhood electric vehicles are speed-limited electric battery vehicles. In Washington state, NEVs are allowed on roads where the posted speed limit is 35 mph or less. For more information view the RCW 46.61.725 page.

Speed Bumps, Humps & Tables

Although we get a large number or requests, we do not install speed bumps, humps, or tables on County roads due to their drawbacks and costs.