WSDOT expanding operation hours for Walnut Street ramp meter

Ramp Meter

SPOKANE, Wash — The Washington State Department of Transportation is expanding the hours of operation for the Walnut Street ramp meter. 

The new hours of operation, beginning Tuesday, June 8, are 6 a.m. to 6 p.m., Monday through Friday. The current hours are 6 a.m. to 9 a.m. and 2 p.m. to 6 p.m.

The ramp meters were activated in April to reduce collisions, relieve congestion and improve the safety of public traveling. The Walnut Street to eastbound I-90 ramp has historically had the highest number of collisions of all ramps metered on the system due to the short merge onto the interstate.

“Metering the ramp from 6 a.m. to 6 p.m. will break up platoons, in an effort to reduce collisions, by creating a more homogeneous merge onto I-90 for the largest volume hours of the day,” said WSDOT traffic engineer Glenn Wagemann.

WSDOT engineers are continuing to fine-tune ramp meter operations and closely monitor traffic at each ramp, and have created a video to show drivers how to navigate each ramp meter.

After Spokane’s first ramp meter was installed in 2019, there was an estimated 69 percent reduction in collisions. The number of reported injury collisions was reduced from seven to zero in the same time period. Because of those positive results, WSDOT expects the same for the new ramp meter locations and updated hours.

The design and installation of these ramp meters were identified as the best practical solution to address collisions in a 2018 comprehensive study. This study evaluated multiple strategies staged at I-90 from SR 904 to Idaho. Local agencies, transit, freight, businesses, school districts, emergency medical services, and neighborhoods representing stakeholders reviewed the findings within their networks and made recommendations on the final solution.

How ramp meters work

Ramp meters are traffic signals that operate according to real-time conditions on the highway and ramp. They provide consistent gaps between vehicles, and prevent the flooding or platooning of cars onto the highway at once.

Data collection devices gather information including the volume, occupancy, and speed of traffic, which is fed into an algorithm which makes adjustments to the meters to control the flow of vehicles onto the interstate.

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