Montlake SR-520 Expansion Contract Comes in $30 Million Over Budget


The Washington State Department of Transportation (WSDOT) will pay a contracting firm $455 million to complete the next phase of freeway expansion through central Seattle: a rebuild of SR-520’s Montlake interchange. That is $30 million more than the $425 million maximum originally budgeted for the project, which includes a lid over the freeway, improved bike and pedestrian access on a parallel route, an added lane on SR-520 for eastbound traffic, and additional lanes over the freeway on Montlake Boulevard.

The additional $30 million, first reported by Mike Lindblom at the Seattle Times, doesn’t mean that the project has been put on hold or its timeline has been delayed–WSDOT’s overall budget still has $1 billion allocated for the remaining segments of expanded freeway infrastructure for the SR-520 corridor, though of course those segments could also end up costing more than originally estimated. High labor and construction materials costs continue to plague almost all of the Seattle area’s major capital improvement projects, but highway projects like this one don’t seem to draw nearly as much scrutiny for their cost/benefit analysis as others do. When it comes to freeways, the fiscal conservatives seem to take a nap.

In context, the $30 million increase in the budget for the Montlake Interchange is the entire Move Seattle levy contribution for three badly needed transit corridor improvement projects that will get people out of vehicles: Rainier Ave, NW Market/45th St, and Route 40. Those routes are in dire danger of getting scaled back due to lack of federal partnership opportunities. It’s double the amount spent by the Move Seattle levy on pedestrian safety.

The new Montlake interchange will see more lanes funneling vehicles to and from SR-520 ramps, and those lanes will be wider than they are now, leading to higher speeds. While the plans may change as the contractor completes its design/build contract, the 2016 plans showed the number of lanes over 520 on Montlake Boulevard jumping from six to nine. Neighborhood opposition in Montlake largely has focused on the loss of the nearby market and not on the amount of car infrastructure that will be added to the area.

The current Montlake at 520 intersection. (Google Maps)
Plans for the new Montlake Interchange expand the number of lanes. (WSDOT)

With additional information coming out showing just how urgently our society will need to adapt to avoid catastrophic impacts due to climate change, projects that have been in motion for years, such as the several billion dollars being spent to improve the connections between I-5 and 520, might need to be reassessed, but, without the leadership at the state level to do so, the bureaucracy continue as normal at WSDOT. Governor Jay Inslee is currently campaigning hard for what could be the country’s first state-based carbon fee while at the same time his state government is steaming ahead at full speed with a number of freeway expansion projects that will increase emissions.

Earlier this month, WSDOT announced it projections that traffic on the new SR-99 tunnel replacing the Alaskan Way Viaduct (also surely over budget) will increase to 7,000 vehicles per day, up a third compared to current levels. If those projections are accurate, that’s a significant increase in vehicle emissions, and doesn’t even account for the corresponding increase in surface street traffic that the Seattle Department of Transportation (SDOT) expects to see downtown. For a city that has signed on to the Paris Climate Accords, we are not acting like Paris.

Projected increase in vehicle traffic on highway 99 through central Seattle. (WSDOT)

There is a growing consensus that Portland, Oregon is making a mistake by spending $450 million on adding a lane to I-5 through the Rose Quarter–a mistake it had avoided in past decades when it successfully beat back freeway expansions through its center city. In Seattle, there doesn’t seem to be a similar consensus forming. It’s likely that Washington state residents will see it differently in the coming decades.

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Ryan Packer lives in the Summit Slope neighborhood of Capitol Hill and has been writing for the blog since 2015. They report on multimodal transportation issues, #VisionZero, preservation, and local politics. They believe in using Seattle's history to help attain the vibrant, diverse city that we all wish to inhabit. In December 2020, Ryan started a three-month stint as editor of Seattle Bike Blog.

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“There is a growing consensus that Portland, Oregon is making a mistake by spending $450 million on adding a lane to I-5 through the Rose Quarter…”

That’s a lie. The Rose Quarter I-5 ‘auxiliary lane’ improvements for exit and entrance ramps should reduce the high accident rate. Surface street improvements bode well for pedestrian and bicycling. There is no growing concensus that it’s a mistake. Just the opposite, care you Seattlers ever choose to investigate the facts.

Howard Metzenberg

This proposal adds new capacity for motor vehicles to the interchange, yet the real bottlenecks for vehicles moving through the neighborhood are elsewhere, at points both north and south of the interchange, including the drawbridge, the stadium, the hospital, and the Montlake business district. This project will simply move the daily traffic jams to other points on this north-south corridor, especially with cars also being diverted away from the Arboretum. The new choke points are obvious.

The freeway lid is an expensive bauble that adds a small amount of low quality green space to a neighborhood that already has sufficent green space, much of it badly utilized and some of it choked by invasive weeds. Why not instead improve the flow of buses, bicycles, and pedestrians through this north-south bottleneck by creating alternative, higher capacity solutions for crossing the ship canal, like a dedicated bridge that serves alternative transportation for Husky Stadium and light rail?

Mike S

Appreciate the article, but I think there are a few aspects that are not fully considered here. In particular the number of lanes in the Montlake-520 interchange continues to be a target. But in reality, I think the design is in the right direction. Today the choke points of left turns, u-turns, etc. creates the substantial bottlenecks that extend traffic back significantly in every direction.

Adding additional turns lanes and creating easier flow of traffic entering/exiting 520 will substantially improve the traffic conditions on streets through the Montlake area by improving flow in these critical intersections. Without this improvement I think you’d see a massive investment that does nothing to improve travel times in the area, which significantly impacts transit. Reducing the choke points is necessary to improving the broader network. Obviously just my opinion, but so much of the backup is due to terrible setup in this area that I think the new design really will improve overall quality / experience in the area.

But I think a lot of the problem here is around the climate argument. Making a climate argument about investments into SR-99 and SR-520 ignores a lot of other beneficial aspects and doesn’t totally hold water in my opinion.

Equating increased usage of the SR-99 tunnel to increased emissions really isn’t that black and white – a lot of those increased trips may just be diverted from other corridors and the total emissions increase probably isn’t that great compared to the alternative of vehicles idling and spending longer in traffic because of a lack of alternatives (i.e. no tunnel). Similarly with the 520 interchange, I’d expect the net benefit of nine lanes improving overall flow and access to 520 may potentially reduce overall emissions by reducing the miles long gridlock in each direction of idling cars.

Additionally, mobility is crucial to the future of our region – both economically and environmentally. I fully agree that more should be invested in non-car transportation, but without the infrastructure in place to reduce some of the gridlock, transit cannot benefit. It is a chicken and egg situation, but without the right corridors and options in place to allow transit to move more freely in and out of the city, less people will choose transit. Increasing the number of bus options does not necessarily equal greater bus ridership.

I think this article ignore a lot of the connection and flow aspects and should be less focused on freeway expansion. The adage of build it and they will come with freeway projects is certainly still valid, but I think our bigger problem is that we haven’t built it and all those people are already here.

Andrew Barash

One of the main reasons there will be more vehicle (car, and bus) lanes on Montlake Blvd over SR-520 is the closure of the Arboretum on/off ramps. There was a strong desire by the neighboring communities to no longer have the Arboretum connect to the freeway, so all traffic is routed to Montlake Blvd instead. So now Montlake Blvd will handle the former arboretum traffic (from Madison Park/Valley and Rainier Valley).

Brian Nelson

Not sure why you’re comparing/contrasting a state project with 3 city projects – as I’m sure you know they’re authorized by different municipals and appropriated by separate funding streams. The Montlake 520 interchange is a WSDOT high priority project, that even though is 7% over the original estimated budget, comes with a ridiculously high benefit-to-cost ratio. If you’re truly outraged by the increased cost and somehow successfully lobbied to get that additional $30M moved from this project to the Rainier Ave, NW Market/45th St, and Route 40 projects, that would just result in WSDOT de-scoping elements that minimally add benefit e.g. park landscaping and the pedestrian/bicycle land bridge.