Roundabout Will Combat Dangerous Intersection on West Lake Sammamish Pkwy, Says WSDOT

The Washington Department of Transporation (WSDOT) announced building a roundabout at the intersection of the westbound I-90 on- and off-ramps and West Lake Sammamish Parkway S.E./180th Avenue S.E. is scheduled to begin in the next several weeks

Road planners say the project is needed to reduce the risk of serious collisions.

The I-90 to West Lake Sammamish Parkway intersection was the site of 41 collisions from 2006-2010, including one fatal collision, 11 injury collisions, 14 rear-end incidents and 13  involving drivers turning from the off-ramp on to West Lake Sammamish Parkway (WLSP). The roundabout will help reduce the risk of serious collisions at the intersection by controlling the flow of traffic near the on- and off-ramps to WLSP and preventing traffic from backing up onto westbound I-90.

The End Result
The new roundabout at West Lake Sammamish Parkway will help reduce the risk of serious collisions by controlling the flow of traffic near the ramps and preventing traffic backups on westbound I-90.

Project Benefits

Given the nature of the I-90 WLSP intersection, the number of collisions that occur within or near the intersection and increasing traffic volumes, a roundabout is an ideal solution for a few reasons:

• Roundabouts reduce the number and severity of collisions because people drive more slowly through a roundabout.
• With roundabouts, drivers can no longer run a red light or turn left in front of oncoming cars; two situations where severe or fatal injuries are common.
• Roundabouts also help keep traffic moving because drivers only have to yield to others, not stop.

What is the project timeline?

• Winter 2012: we will begin advertising the project for competitive bidding
• March 20, 2013: we awarded the project to Graham-Marshbank JV.
• May 2013: we will begin construction
• Winter 2013: we expect to complete construction