BOTHELL — Commuters will be able to drive on the shoulder of northbound I-405 through Canyon Park for the first time during the Monday evening commute.
The Washington State Department of Transportation plans to open the new “peak-use shoulder lane” to general purpose traffic between Highway 527 and the I-5 interchange in Lynnwood, starting at 2 p.m. Monday.
Drivers and buses will be able to use the 1.8-mile stretch of shoulder during times with the heaviest congestion. Overhead signs will indicate when the shoulder, on the right side only, is open to traffic.
The $7 million project will be paid for with toll revenue from the I-405 express toll lanes.
The state took in more toll income than expected in the first year, pushing the shoulder project ahead of schedule. It originally was slated for spring 2018. The shoulder lane is the first project to be paid for with toll revenue.
Shoulder driving should offer a temporary solution to a frustrating problem for north-end drivers.
The evening commute in Snohomish County is taking longer since the state in 2015 widened I-405 south of Highway 522 and added tolling. Five lanes of traffic are now funneled into three as folks cross the county line.
Long-term plans include adding a second express toll lane at the north end and rebuilding the interchanges at Highway 522 and Highway 527. Lawmakers have set aside money for planning and design work.
Crews have been testing the electronic signs in recent weeks in preparation for activating the system.
What the signs will mean:
A green arrow will indicate when the lane is open.
A red “X” will indicate when it is closed.
Other arrows, in yellow, will tell drivers when to merge or to use extra caution because of an incident ahead.
An additional sign mounted on the side of the signpost can display more detailed information, such as “shoulder blocked,” “shoulder work ahead,” or “slow traffic ahead” and the like.
Traffic in the area is monitored remotely. In case of a crash or other emergency, state crews can change the signs to shift traffic in a way that helps emergency vehicles get through. There also are four paved emergency pullouts for shoulder-lane drivers.
This is the first shoulder driving allowed in the area that is controlled based on real-time traffic conditions.
But using the shoulder to expand highway capacity isn’t new. For example, shoulder driving is allowed during set days and times on the eastbound U.S. 2 trestle between Everett and Lake Stevens.
The state plans to take a similar “dynamic” approach to add shoulder driving on northbound I-5 in Marysville to help with the afternoon slog there.
Melissa Slager: email@example.com, 425-339-3432.