Washington State Department of Transportation will begin charging tolls Monday on a one-mile stretch of State Route 509 between Interstate 5 and 24th Avenue South, creating another toll road option near Seattle-Tacoma International Airport.
The tolls will apply to both directions at the ramps connecting to and from Interstate 5, affecting only the newly constructed expressway portion of SR 509 that opened in late June.
Drivers with Good To Go! passes will pay between $1.20 and $2.40 depending on time of day, with no exemptions for carpools. Those without accounts will receive mail bills including an additional $2 fee.
The expressway represents the first phase of a larger infrastructure project designed to provide a north-south alternative to the heavily congested I-5 corridor through south King County. The route will eventually offer improved freight connections between I-5 and the ports of Tacoma, Seattle, and Sea-Tac Airport.
Construction continues on a two-mile extension that will connect the current expressway to existing SR 509, which currently terminates at South 188th Street near the airport. This additional segment is scheduled for completion in 2028.
Existing portions of SR 509 built before the expressway project will remain toll-free, ensuring that only users of the new infrastructure pay fees.
Tolling will commence at 5 a.m. Monday and serves dual purposes: covering operational and maintenance costs for the new roadway while generating revenue for other components of WSDOT’s Puget Sound Gateway Project.
The SR 509 tolls join Washington’s expanding network of toll roads, which includes I-405 Express Toll Lanes, SR 167 high occupancy toll lanes, the SR 520 Bridge, the SR 99 Tunnel, and the Tacoma Narrows Bridge.
The new toll road reflects WSDOT’s strategy of using dynamic pricing to manage traffic flow while funding infrastructure improvements. Time-of-day pricing aims to encourage off-peak travel and optimize roadway capacity.
The expressway project addresses long-standing transportation challenges in south King County, where limited north-south routes have created persistent bottlenecks affecting both commuter and freight traffic.
Revenue from the tolls will support not only immediate operational needs but also future phases of the Puget Sound Gateway Project, which encompasses broader regional transportation improvements.
The phased opening approach allows WSDOT to begin generating toll revenue while completing remaining construction work on the full expressway connection.
