SR 522 - Snohomish River Bridge to US 2, Four Lane Widening - Completed December 2015

WSDOT widened more than four miles of SR 522 between the Snohomish River Bridge to the US 2 interchange in Monroe from two lanes to four.

The widening included four new bridges, including a new bridges across the Snohomish River, a median barrier to separate oncoming traffic, a new roundabout at 164th Street S.E./Main Street, a noise wall, a wildlife crossing, upgraded lighting and signs.

To create enough space for the widened highway, crews blasted away several hundred thousand cubic yards of rock. Learn more about the blasting work.


How you benefit

Improves safety
Widening the highway and adding a concrete center barrier to separate oncoming traffic reduces the risk of collisions. There were 100 collisions on this stretch of SR 522 from 2006 to 2010, including three fatal collisions.

The roundabout at 164th Street S.E./Main Street also reduces the likelihood of collisions. That intersection was the site of 54 collisions from 2006 to 2010.

Improving traffic flow also reduces the risk of congestion-related collisions such as rear-end and sideswipe. 

Relieves congestion
Added capacity on this stretch of SR 522 improves traffic flow and cuts down on traffic times. The widened highway is in conjunction with a new interchange at US 2 to help relieve congestion in Monroe.

Protects environment
SR 522 travels through some heavily wooded areas that provide habitat for many animals. WSDOT added several features to help reduce the risks of a collision with an animal:

A new wildlife undercrossing not far from the Snohomish River provide deer, coyotes and other animals with a safer route to and from the river.

A new wildlife fences helps reduce the chances that an animal will get close to the highway.

"Jump out" locations in the fence provide a safe spot for deer and other animals that do manage to get close to the highway to find a route to the woods.

In addition, crews built detention ponds to improve water quality. The ponds will collect and filter dirty water, benefiting salmon and other wildlife.


Partnerships & cooperation
WSDOT worked closely with the local communities, Department of Fish and Wildlife and other agencies to plan and complete this project.


Contact us
WSDOT Communications
15700 Dayton Avenue N.
Seattle, WA 98133