Seattle Highway Shutdown Provides Data Sharing Lesson

The planned closure of the Alaskan Way Viaduct in downtown Seattle mobilized collaboration and data sharing across several public transportation agencies, helping to establish new behavior towards commuter travel.

by / August 22, 2019
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In Seattle, a major transportation infrastructure project had the potential to cause huge traffic headaches. But it also introduced car commuters to other forms of commuting, including public transit and biking, while generating new data sharing relationships among public agencies.

Earlier this year, transportation officials began shutting down the Alaskan Way Viaduct, an elevated two-level freeway along the Seattle waterfront, in preparations for demolition. The highway, built in the 1950s, has long been in need of replacement. On Jan. 11, the Washington State Department of Transportation (WSDOT) closed the structure, which averaged nearly 80,000 cars every weekday, for three weeks.

“It was the longest highway closure in the Puget Sound region’s history,” said Heather Marx, director of downtown mobility at the Seattle Department of Transportation, speaking Tuesday during a webinar hosted by Meeting of the Minds, a nonprofit dedicated to studying smart cities issues and solutions.

The shutdown would affect thousands of daily commuters and others coming into Seattle's busy downtown, prompting a cross-agency approach to rerouting bus lines and changing transportation behaviors in an effort to mitigate the expected upsurge in traffic congestion.

“We were concerned that the rest of the network wasn’t going to successfully be able to absorb all of those trips,” said Marx in comments during the webinar titled "Democratized Data Access: the Key to Managing Urban Mobility in Cities."

The enormity of the project forced collaboration across several agencies, including Seattle DoT, WSDOT, the Port of Seattle, King County Metro Transit and Sound Transit, in ways that were both aspirational and difficult, according to Marx.

“Everybody wants to work together. Everybody has the intention of working together. But, every different government has different procurement rules, and different procurement processes, and different internal audiences,” he said.

The project demonstrated the need for data sharing among agencies, not only for the large once-in-a-generation sort of projects, but also in the more day-to-day workings of urban mobility.

“We’re working hard to keep talking so that we can start sharing data a little bit more seamlessly,” said Marx. “It is my hope that we can all be on a single platform, for some of that more meaningful, consequential data.”

Remix, which provides transportation and transit planning tools to some 300 agencies across the country, pointed out how essential data sharing is in a quickly shifting mobility landscape.

“Transportation has changed more in the last five years than in the last 50,” said Rachel Zack, a policy strategist at Remix, during Tuesday’s webinar. “Where transportation was felt to be relatively understood, new modes are changing how people are getting around, in a way that is operating much more quickly than sort of the tools we have in our agencies to react.”

The data-driven planning tools Remix provides are developed with a goal of sharing data across departments.

“We want the street planners to talk to the transit planners and the new mobility planners in a way that they’re all referencing the same information,” said Zack.

“The idea of everybody having access to some of the most basic pieces of information, and to be able to visualize that, each on their own, is actually quite game-changing,” she added.

In the end, the cross-agency planning to close the Alaska Viaduct proved to be a success with the traffic mitigation plan going off, “kind of, without a hitch,” said Marx.

The effort was a far-reaching education campaign to encourage transit use and reduce single-occupancy trips. It worked, in part, said Marx, because, “I think everybody really understood how high the stakes were.”

Overall volume of vehicles was down 10 percent, with significant increases in light rail ridership and bicycle use. “We had something like a 200 percent increase in bicycle ridership,” said Marx. “And this is in January.” 

Employers also tested out the idea of working remote. None of the mitigation strategies were entirely shelved once the three-week closure came to an end. The replacement of the highway is an enormous infrastructure project with more traffic disruptions to follow.

Anecdotally, said Marx, a number of commuters “made the change out of necessity, and then found they really preferred the changed behavior. They really preferred riding the bus. Or they really preferred riding their bike.

“Big things like this help broaden the bounds of ... thought for how people get around,” she added. “And so, somebody who does something once out of necessity might find that it’s actually better. And so I think that’s what we’re trying to build for the long term.”

Skip Descant Staff Writer

Skip Descant writes about smart cities, the Internet of Things, transportation and other areas. He spent more than 12 years reporting for daily newspapers in Mississippi, Arkansas, Louisiana and California. He lives in downtown Sacramento.

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