Using proceeds from Interstate 405 express toll lanes, the Washington State Dept of Transportation plans to add even more capacity on I-405 in the form of a shoulder lane.

With heavy congestion plaguing the greater Seattle area on Interstate 5, I-405 hasn’t provided much of a traffic-free alternative. Already WSDOT has introduced express toll lanes—to limited success—both northbound and southbound near Bellevue, but the latest effort centers around adding new lane capacity between State Route 527 and I-5 to further help relieve congestion.

The focus of the new project will be to build a northbound peak-use shoulder lane—also known as hard shoulder running—for 1.8 miles. The project also comes with a new noise wall along I-405.

The department will use overhead lane controls signs to display whether the peak-use shoulder lane is open to traffic, which the department plans for sometime roughly between 3 and 7 p.m., the heaviest time period for northbound movement on the freeway.

Vehicles over 10,000 gross vehicle weight, except for buses, will be prohibited from using the lane.

In a statement, WSDOT says, “By building more capacity to handle the large volumes of traffic entering I-405 from SR 527, we expect to improve congestion that travelers are experiencing, especially in the area near the SR 522 interchange, where I-405 has less capacity.”

This project comes during a time when state officials are working to find a longer-term solution to ease congestion in the area.

Construction will start on the 1.8-mile stretch of shoulder lane in late 2016 or early 2017 following a late fall 2016 contract award. WSDOT expect the lane to open by summer 2017.

Follow Tim Newcomb on Twitter at @tdnewcomb.