April 25, 2024
How do you add a new lane onto northbound I-5 in downtown Seattle without a huge mega-project? You get creative and use what you have.

How do you add another lane onto northbound I-5 in downtown Seattle without a huge mega-project? You get creative and use what you have.
Northbound I-5 will have another full lane going into and through downtown Seattle, sometime over the next week or so.
More Chokepoints: WSDOT to address I-5 chokepoints between Everett, Marysville
The Washington Department of Transportation (WSDOT) has spent the last two years moving a barrier and eking-out 1,500 feet to extend the exit lane at Seneca Street through where University Street joins the freeway.
Sometime over the next week, you will have the choice of exiting at Seneca or just going through. There will be three through lanes into downtown for the first time. 
“We didn’t have to add on to the freeway to do this,” WSDOT’s Amy Moreno said. “We worked within our footprint. We just moved the barrier and created that extra capacity.”
This extra lane should really help the daily congestion into downtown.
But to put the finishing touches on this lane, and to continue with the other improvements in the same area, there are some big closures coming this week. 
“We will be closing lanes on the main line one night, closing lanes in the [collector-distributor lanes] and going back and forth but really the two main full closures are going to be Tuesday night and Saturday night,” Moreno said.
Those two nights, only the northbound I-5 express lanes will be open. The mainline of I-5 will close around 9 p.m. The collector-distributor lanes will close at about midnight.
There will be no direct access from I-90 to I-5 during those four hours. 
“If you’re heading into downtown, get off at Edgar Martinez Drive,” Moreno said. “If you’re coming over from I-90, there is a detour route you need to take.”
What is the state doing with those collector-distributor lanes?
I have been warning you for a few years now that ramp meters would be going in. They went up earlier this year. More signs are going in. And sometime this fall, those ramp meters will go active.
Moreno said they are needed to better regulate the traffic both in the collector-distributor lanes and on the mainline. 
“You think about I-90 and I-5 congregating in that spot,” she said. “Two huge interstates coming together, and they just kind of, to borrow into your terms, create a chokepoint.”
More on the new I-5 lane through Seattle: WSDOT adding ramp meters to I-90/I-5 connection in Seattle
A lot of people have asked me how or why is the state putting red lights on the freeway. You have to understand those lanes are part of a ramp system and not actually part of the freeway. 
“It is a connection ramp, and this is not the first time this has been done,” Moreno said. “A lot of studies have shown in these cases it actually helps the flow of traffic.”
I know this is a distinction or technicality that doesn’t matter to you, but that’s the reasoning. 
“The collector-distributor is technically a ramp right there, which is tough for people on I-90 because they were just speeding on a freeway,” Moreno said. “You are connecting now to a another interstate, and hopefully once those ramp meters go up everyone’s gonna see the benefit they’re going to bring.”
The state will give drivers a few weeks notice of when those meters will go active this fall, and I’ll be tracking that timing carefully.
But for now, the big change to I-5 will be the addition of that third through lane at Seneca.
Follow @https://twitter.com/newsguysully