Report lauds effort to keep Puget Sound highway traffic moving

Congestion is returning to U.S. highways, but Seattle has been more successful than most regions in fighting the trend, according to INRIX, the Kirkland-based traffic-data firm.

The company's latest annual report, "Back on the Road to Gridlock," says that after traffic plummeted during the Great Recession, it worsened in 2010 as the economy began to recover. Overall, traffic increased about 1 percent nationally.

Seattle-Tacoma-Bellevue ranked No. 8 in peak-time congestion, with a "Travel Time Tax" of 19.8 percent. That means an average trip took nearly 20 percent longer during the afternoon commute than it would have if drivers had been able to travel near the speed limit. Los Angeles ranked No. 1, with a 35.4 percent time loss. The national average is 9.7 percent.

What didn't happen around here was a quick bounce back to 2006 gridlock, when area drivers endured an average 29 percent afternoon delay.

"Seattle appears to be an interesting case where a combination of strategic construction projects and aggressive operations of the network are yielding improvements," says the report, to be published Tuesday. The company suggests adding capacity or reducing volumes in the worst bottlenecks.

The findings, based on data from vehicle-navigation devices and smartphones, do not deal with travel times on buses, trains, bicycles or foot.

INRIX praises Washington state's new variable speed-limit signs on Seattle-area freeways, its rapid response crews to clear stalled cars from highways and programs to boost telecommuting and ride-sharing.

Traffic both here and nationally still hasn't reverted to pre-recession levels but will soon, the report says.

The worst bottlenecks here are Interstate 5 southbound at the University District, Highway 16 in Tacoma approaching I-5; and Highway 520 at the east shore of Lake Washington. The most congested corridors are Interstate 405 southbound through Bellevue and Highway 16 eastbound from the Narrows Bridge to I-5.

Mike Lindblom: 206-515-5631 or mlindblom@seattletimes.com