What will drivers see when the project is completed in 2014?
- An additional lane in each direction from just west of the Snohomish River Bridge to 179th Avenue SE in Monroe (more than four miles)
- Roundabout at 164th Street SE on the northwest side of SR 522 to help improve traffic flow at the interchange
- Median barrier to separate oncoming traffic and reduce the risk of head-on collisions
- Four new bridges – including 1700-foot bridge over Snohomish River – that will carry westbound traffic
- A new noise wall near 171st Avenue SE and taller barrier to help reduce noise
- Wildlife crossing to provide safe passage for fish and animals and reduce the risk of collisions involving wildlife
What can drivers expect during construction?
Drivers should plan for lane closures on SR 522 from 9 p.m. to 5 a.m. Sunday through Thursday nights, as well as closures of 154th Street SE, 164th Street SE and 179th Avenue SE. Drivers can also expect full closures of SR 522 from 10:15 a.m. to 11:15 a.m. on weekdays when rock blasting starts in July 2012. Bookmark our construction update report to stay on top of upcoming closures.
Why is WSDOT widening SR 522 to four lanes?
Nearly 28,000 vehicles travel this stretch of SR 522 each day. Drivers experience heavy congestion and delays. We will add a new lane in each direction to add capacity, which will help improve traffic flow and cut down on drive times. Widening the roadway will also help reduce the risk of collisions.
This work is the next phase of our project to add a new ramp from eastbound SR 522 to eastbound US 2 to help relieve congestion at the SR 522/US 2 interchange.
Why is WSDOT building a new roundabout at SR 522 and 164th Street SE?
When we designed the SR 522 widening project we looked at ways to improve traffic flow and safety at the 164th Street SE interchange. Whenever we look at changing an intersection, we evaluate a variety of options, including turn lanes, signals and roundabouts. We also look at current and projected traffic volumes. In this case, we determined that the existing intersection will not be able to handle future traffic volumes. Our analysis showed that the roundabout is the best long-term solution for the intersection and would produce the shortest delays and backups for traffic.
When compared with traditional signalized intersections, roundabouts can handle more cars per hour and with less congestion on approaching roads. Roundabouts promote a continuous flow of traffic; drivers go through the intersection at a slow speed, rather than coming to a complete stop for a signal. Roundabouts are also safer than traditional stop sign or signal-controlled intersections. Studies have shown that roundabouts reduced injury crashes by 75 percent at intersections where stop signs or signals were previously used for traffic control. Learn more about roundabouts and their benefits.
We will build the new roundabout on the northwest side of SR 522 and realign the westbound SR 522 on- and off-ramps. We will also add a shared-use path for pedestrians and bicycles along 164th Street SE.
Why is WSDOT installing median barrier on SR 522?
There were 100 collisions on this stretch of mainline SR 522 from 2006 to 2010, including three fatal collisions and one serious injury collision. The median barrier will separate opposing lanes of traffic, reducing the potential for serious head-on collisions. We are also installing 42” barrier on the shoulder of SR 522 north of 164th Street SE.
Why is WSDOT installing a wildlife crossing?
There were 13 reported collisions involving wildlife on this stretch of SR 522 from 2006 to 2010. We’re replacing two fish barriers with a new fish-friendly culvert that will also allow for deer and small mammals to pass under the highway. The project will also include fencing to help guide wildlife to the safe crossing under SR 522. Learn more about WSDOT’s fish and wildlife efforts.
How did we determine where the noise wall would be built?
We consider a variety of factors, including future noise levels and cost effectiveness, when determining whether to build a noise barrier; we follow state and federal guidelines in making those decisions. Learn more about WSDOT's noise program.
We conducted a noise study for neighborhoods near SR 522 during the project design phase. We measured current noise levels and modeled future noise levels based on future traffic volumes. The noise study showed that future noise levels for the neighborhood on the northwest side of SR 522 between 171st Avenue SE and Mountain View Road SE would exceed 66 decibels, which is our threshold for considering a noise wall. This neighborhood also met the WSDOT cost-effective criteria for a 9- to 10-foot noise wall along the westbound lanes of SR 522.
In addition to the noise wall, we are also installing 42-inch concrete barrier along the outside lanes of SR 522 between 164th Street SE and 154th Street SE – ten inches taller than the barrier we typically use on this type of project. The barrier will help prevent vehicles from leaving the roadway and as a side benefit will provide a visual shield and reduce tire pavement noise. We expect the additional height to reduce noise levels by 1-2 decibels, a change that is not typically perceptible to the human ear.
Visit our SR 522 rock blasting page for graphics and a video
We will widen SR 522 to the northwest of the existing roadway. In order to create space for the new roadway, we must blast and remove 300,000 cubic yards of rock.
What can drivers expect during the rock blasting work?
To keep crews and drivers safe during the blasting work, we must fully close SR 522 for an hour at a time. The closures are currently scheduled for 10:15 to 11:15 a.m. on weekdays and are expected to start summer 2012. During the closures, drivers can choose alternate routes or follow a detour using SR 9 and US 2.
How will WSDOT notify residents, drivers and emergency responders about scheduled blasting work?
We will use electronic message signs and highway advisory radio to alert drivers and residents to upcoming closures. We will also provide the information on our project hotline (1-877-832-0303). Crews will also provide advance notice to emergency responders .
How can drivers and residents stay informed about the project?