Why there are bumps along I-5 through downtown Seattle (and when they’ll go away)

Oct 12, 2021, 5:05 AM | Updated: 10:27 am
I-5, bumps...
I-5 near downtown Seattle. (WSDOT file photo/Flickr)
(WSDOT file photo/Flickr)

When KIRO Radio’s Dave Ross asks you to update something for him, you do it.

When discussing traffic on Seattle’s Morning News on Monday morning, Dave asked me about those annoying bumps on I-5 southbound out of downtown Seattle. They showed up after new pavement was installed between downtown Seattle and the West Seattle Bridge, and they were supposed to be taken care of during the recent lane closures.

Here’s the latest:

The expansion joint replacement work that is part of the Revive I-5 project has only replaced six of the 40 joints so far. That has left 34 bumps in the road that the state will get to next construction season. But don’t worry: You won’t have to deal with those big bumps until next year. The contractor has been working at night to smooth them down, and that work will be done soon.

“They’re carving these little ramps from the concrete to the expansion joint level,” the Washington State Department of Transportation’s Tom Pearce explained. “It’s a four-to-one ramp. The average drop is about an inch. They are carving about four inches back on either side of the pavement. That’s not going to eliminate the bump, but it is going to lessen it.”

Those smoothed-down bumps will remain until the joints are replaced next year. Pearce drove over some of the smoothed bumps recently, and he said they were a lot better.

So why did WSDOT pave first and not replace the expansion joints first?

“It’s a more efficient process to repave and then replace the expansion joints because it’s just easier to match the expansion joint height to the pavement, rather than match the pavement to expansion joint height,” Pearce said.

That’s our bump update.

Why are portions of I-90 near Snoqualmie Pass so ‘groovy’?

This weekend, WSDOT is set to start the serious work of adding 1,500 feet of new road to I-5 northbound. This is something I have been talking about for several years.

WSDOT is going to convert the Seneca Street exit only ramp into a through lane so northbound drivers can exit at Seneca if they want, or continue straight on I-5 if they want do that. That lane will eventually connect to the University on-ramp, 1,500 feet up I-5.

Pearce said the contractor plans to close the I-5 northbound collector-distributor lanes overnight on Saturday and Sunday to start creating a work zone.

“We need to move some barrier on northbound I-5 in the Seneca area,” he said. “What that’s going to do is provide us a little more room so we can come back and re-stripe northbound I-5 in that area so there’s actually three through lanes.”

This work is weather dependent, and the forecast is a little iffy. If the work goes forward, it is going to make getting off in downtown Seattle difficult.

“That’s going to mean that the I-90 ramps to northbound I-5 will be closed,” Pearce said. “The Dearborn on-ramp is also going to be closed. The northbound off-ramps to James and Madison Streets will also be closed.”

But you will still be able to get to eastbound I-90. The C/D lanes will close after that ramp.

This new 1,500 feet of I-5 northbound should be finished by next fall. The two C/D lanes to I-5 will also be metered at the same time. There will also be a new ramp meter at the Cherry Street on-ramp to northbound I-5.

Check out more of Chris’ Chokepoints.


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Why there are bumps along I-5 through downtown Seattle (and when they’ll go away)