I-5 - Olympia Area Southbound - Congestion Management

Project news

  • Beginning Tuesday, Aug. 18, WSDOT will activate new southbound I-5 ramp meters in Lacey and Olympia.  
  • These ramp meters are located at Martin Way East Sleater-Kinney Road Southeast, Pacific Avenue Southeast and Henderson Boulevard Southeast.
  • Sign up for email updates on this project and other major roadwork on state highways in Thurston County. 

Needs & benefits

Multiple vehicles merging onto the highway at the same time contributes to southbound I-5 congestion between Lacey and Olympia. A platoon of merging vehicles will cause drivers using I-5 to change lanes or slow down. This has a cumulative affect similar to damming a river that contributes to congestion.

Ramp meters pace the flow of merging traffic. A short wait at a traffic signal on the on-ramp helps break up the platoon of vehicles. When vehicles enter the highway in controlled intervals, those vehicles are less likely to disrupt highway flow.

Overall, highway drivers increase their average highway speeds and shorten overall highway travel times. Ramp meters also help reduce the potential for collisions when multiple vehicles merge onto the highway at the same time.


March 2019 - Project advertised for bidding
April 2019 - Project awarded private contractor
Spring 2019 - Construction began
April 2020 - Project complete


Financial Data for PIN 300519Q
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $0
Pre-Existing Funds (PEF) $550
CWA $0
Total $550


Brian Whitehouse
Lacey Project Engineer Office

Doug Adamson
WSDOT Media Relations

I-5 Olympia Area Southbound Congestion Management project vicinity map