Call it a clog, a slow-down, a standstill or some other colorful phrase, merging onto I-5 from Mercer Street in Seattle can be a trying experience, with backups extending beyond the length of the on-ramp to I-5. Also exasperating- the I-5 drive through Seattle as the onslaught of slow-merging vehicles brings freeway traffic to a halt.
Beginning Saturday, March 10, the merge will look a little different. New signals installed on the ramps from Mercer Street to both northbound and southbound I-5 will help to pace the merging vehicles. For the first month, the signals will meter traffic during the weekends. After a month of monitoring and evaluating the metered traffic, our engineers will turn on the signals during the week as well. Weekday metering will start Tuesday, April 17.
Take a peek at this animation to get a feel of how the new configuration will work:
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.
|Drivers waiting on the Mercer Street on-ramps to northbound and southbound I-5|
Benefits of ramp metering
Many of us can feel a bit stressed looking ahead to merging traffic. Whether merging lanes or merging from the on-ramp to the freeway, predicting fellow driver behavior can be taxing. The new signals will help to ease some of the anxiety by alternating traffic and taking out the guesswork. Ramp meters also typically:
- Create steadier flow of traffic onto the freeway
- Reduce freeway travel times
- Reduce the severity and number of collisions due to merging traffic
We are confident the new meters at this major downtown intersection will help move traffic out of the city safely and with more consistency.