Published August 15 2016
To improve traffic flow on Interstate 405, especially during peak commute times, the state Department of Transportation is adding a meter to the on-ramp from Coal Creek Parkway/Lake Washington Boulevard onto southbound I-405. Activation will be on Wednesday.
Since 1967, the state Department of Transportation has used ramp meters to improve safety and traffic flow on several of Washingtons urban freeway systems.
WSDOT engineers partnered with Bellevue transportation engineers to design a ramp meter that both regulates the flow of traffic onto the freeway while also managing the queuing leading onto the freeway ramp. WSDOT's blog explains the coordination involved.
- The ramp meter is installed as far down the on-ramp as possible.
- Instead of one lane, the ramp has two to hold more vehicles.
- The ramp meter detection is connected with Bellevue's nearby traffic signal to coordinate the two systems.
- A "No Right Turn on Red" sign for southbound Lake Washington Boulevard will be activated while the ramp meter is on, to help balance the flow of traffic with the left turns from Coal Creek Parkway.