Traffic analysts predict commute times may increase 50% for many drivers when viaduct closes

SEATTLE -- If you are one of the tens of thousands of drivers who commute on the Alaskan Way Viaduct each day, your commute time starting Friday morning could take 50 percent longer.

“Right now the prediction somewhere in the lines of ...  50% more in travel time,” said Lytang Kelley, analytics market manager for Inrix, a Kirkland-based traffic data company.

Inrix says if you drive in the downtown core and come in to the city on I-5 .your commute will be 50% longer -- so if it`s normally an hour, plan on an hour and a half.

Areas that connect with I-5 like I-90, SR 520 and SR 522 will likely take 20% longer, according to Inrix.

“The ripple effect will be felt elsewhere,” Kelley said.

And those delays are not even taking fender-benders or other accidents into consideration.

“There are a lot of times when traffic is bad with or without the viaduct closed,” said Jon Layzer, of the Seattle Department of Transportation.

In 2011, when the Washington State Department of Transportation closed the viaduct for a week, traffic wasn`t bad the first few days, but as time went on people went back to their old habits and traffic got much worse. If history is any indication, the gridlock could be worse next week than this Friday.

“People go back to their old habits in the course of the closure. In 2011, we saw that in the fifth and sixth day of the closure,” David Sowers with WSDOT said.

So, transportation planners are encouraging people to ditch the car and use other modes of transportation.

“This is really an opportunity for people to try out something different and contribute to the solution,” Layzer said.