WSDOT to install ramp meters for drivers getting on I-5 from Mercer Street


SEATTLE -- New ramp meters will be installed and tested at the Mercer Street on-ramps to north and southbound Interstate 5.

Traffic engineers at WSDOT say the goal is to ease congestion for drivers on I-5 passing through the downtown Seattle area.

The new signals will start pacing vehicles entering the freeway on weekends only starting March 10. After a month, crews will evaluate the metered traffic and could turn on the ramp meters for weekday traffic as early as April 10.


How will the ramps work?

Here's WSDOT's explanation:

"On Mercer Street, once you cross Fairview Avenue, you will have two lanes on the ramp to northbound I-5 and three lanes on the ramp to southbound I-5 where you can wait for your green light to merge onto the freeway. The signals will alternate traffic from each lane, and instead of a clogged ramp, picture more of a slow leak of vehicles onto I-5. Gaps between merging vehicles will make the merge easier and reduce the risk of collisions near the I-5 on-ramps.

"Traffic engineers will monitor congestion and travel times on I-5 to determine when to turn on ramp metering. In coordination with the Seattle Department of Transportation, they will also monitor and adjust the ramp metering when it is active. As far as backups and delays on Mercer Street itself, engineers do not expect any negative effect."

You can find more information on WSDOT's website here.