New data: Viaduct closure hasn't made traffic much worse


Traffic on the now-closed Alaskan Way Viaduct.

A full week has passed since the End of the World for Seattle commuters, aka the closure of the Alaskan Way Viaduct. But has "Viadoom" (or Vimaggedon or Apocaduct, if you prefer) made things significantly worse, as once predicted? According to the data from Inrix, a local traffic analytics firm, not really.

In news coverage leading up to "Viadeath 2016," Inrix provide the official data forecasts for Seattle’s traffic snarls. The company predicted commute times would increase by 50 percent, a statistic quoted in the Seattle Times,, Q13 and the Puget Sound Business Journal. Through sensors in commercial vehicles, Bluetooth devices and smartphone apps, Inrix creates a sort of digital web of traffic information. The company's mission is to provide accurate and immediate data on how traffic in urban centers like Seattle works.

But in an email exchange with Crosscut, a representative speaking on behalf of Inrix backpedaled on those initial predictions, saying that, “According to INRIX’s analysis, commute times have not dramatically increased and several of the major routes into the city have been only moderately affected.”

“Drivers have handled the closure well!” she said.

According to analytics market manager with Inrix, Lytang Kelley, travel times have been longer, but not astronomically. On I-5, travel time has increased by about five minutes, and rush hour has shifted toward 6 a.m. as people allow themselves more time to get into work. The same goes for the West Seattle bridge, on which travel times have jumped about five minutes. On I-90 Westbound, commutes have only increased by between three and five minutes. And on 520, traffic’s about normal.

Asked about roads like notorious traffic hotspot Mercer Street, Kelley responded that speeds have been slightly slower than normal going eastbound, but that travel times have increased by around five minutes at the most. Travel times on Denny Way have also increased slightly, she said.

There are obvious holes in these numbers, mostly with regards to non-highway traffic. But simply put, commutes are not 50 percent worse.

Do the folks in our local traffic agencies agree? In a conference call Friday, representatives from WSDOT and SDOT weren’t jumping out of their seats to say traffic is fine.

“We’re seeing about what we expected,” said Jonathan Layzer of SDOT. While Aurora Avenue north of the Battery Street tunnel is predictably light, Layzer said that they were seeing I-5 congestion spill onto east and west streets and that arterials on the south end of downtown were seeing heavy congestion. Most significantly, though, the entire system is much more fragile, so any traffic incident on I-5 has a much larger ripple effect than when the viaduct is open.

Traffic in Seattle is awful, as always, and the widespread misery is justified. If commuters feel like they're waiting longer in traffic, they're right. But the adjustments of their fellow commuters have made the End Times more palatable. The trick now is for drivers to keep it up and not return to old habits.

This story has been updated.


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About the Authors & Contributors

David Kroman

David Kroman

David Kroman is formerly a reporter at Crosscut, where he covered city politics.