Friday, June 24, 2016

To switch or not to switch

By Justin Fujioka

Why am I sitting in a backup while the other direction has the express lanes open with free flowing traffic? I’m sure this has gone through the minds of many of you at some point – including me.

While it’s not exactly in their job description, our traffic engineers must sometimes be performers in a careful balancing act – which direction will the express lanes relieve the most congestion from Seattle’s entire transportation system.

The key phrase here when it comes to Thursday evening’s rainy and rough commute across Lake Washington is “entire transportation system.”

Every weekday, the I-90 express lanes open eastbound at 2 p.m. because our traffic data shows much more traffic heads out of Seattle than into town from mid-afternoon to late evening. And by 5:30 p.m. Thursday, traffic going east across Lake Washington was extra heavy because of a collision that blocked the left lane of eastbound SR 520 near Montlake Boulevard.

So when a jackknifed semi crashed just before 6 p.m. and blocked the two right lanes of westbound I-90 in the Mt. Baker Tunnel, a difficult choice had to be made: To switch or not to switch.

Switching the I-90 express lanes takes at least an hour – and even longer when there is congestion. That’s because our crews have to sit in traffic to get to the express lanes gates to close them. Crews must then check the lanes to confirm that all traffic has cleared and that all signage and gates are in place.

Closing the express lanes during the peak of the commute would have likely led to major eastbound congestion that would back up onto I-5 in Seattle. Keep in mind, eastbound SR 520 traffic was already hosed because of the crash near Montlake and already spilling onto I-5. Seattle to Bellevue travel times on SR 520 peaked near 70 minutes.

Shortly before 7 p.m., engineers addressed “the switch” again. One lane of eastbound SR 520 was still blocked because the tow truck that needed to clear a vehicle was also stuck in eastbound traffic. Of course, westbound traffic was brutal as well, with Bellevue to Seattle travel times on I-90 at close to 90 minutes.

Crews on scene at the I-90 semi collision reported to our Transportation Management Center that all that was needed was for tow to arrive and estimated a clearing time at one hour. Remember, one hour is also the minimum time it takes to switch the express lanes. That means one hour with no traffic in the I-90 express lanes. It would’ve been a disservice to thousands of additional vehicles going eastbound. All lanes reopened just after 8 p.m.

Our main job is to keep traffic moving safely on all of our highways. And that’s why a decision was made to not switch the I-90 express lanes, at the risk of creating additional backups on other corridors in our transportation system.


Helena said...

If WSDOTS goal is to keep traffic moving, then why are you still extorting the public and creating massive traffic jams on I405 with the extortion toll lanes???

Dusty Jewett said...

Because EastSide has consistently decided that busses-on-interstates is better than off-street mass transit. In order to keep the busses moving, there have to be HOV lanes.

WSDOT comment policy

Post a Comment