New viaduct speediest option, studies show

It's a 10-minute advantage.

If the Alaskan Way Viaduct were replaced by another elevated highway, a driver making his way from Seattle's Greenwood neighborhood to Seattle-Tacoma International Airport would arrive 10 minutes sooner than if the replacement were a surface boulevard, according to findings released Thursday by the Washington Department of Transportation.

Research shows such a trip during the afternoon commute would take 47 minutes on a surface boulevard and 37 on an elevated viaduct.

Travel time is just one part of a complicated mosaic of 27 measures that will be used to make a final decision among eight viaduct-replacement options under consideration. On Thursday the state released its analyses of trip times — on elevated roadways, on surface boulevards and in tunnels.

The state plans to narrow the eight replacement options to three in December and to make the final selection before the end of the year.

Many of the city's industrial leaders have been pushing for another elevated viaduct, and the Department of Transportation (DOT) travel-time study did find it would save time for freight. From First Avenue South to Interbay on the viaduct during the morning commute would take 16 minutes on an elevated viaduct, compared with as much as 26 minutes on a surface street. From Ballard to Sodo, during the morning southbound commute, it would take 27 minutes on surface streets, as long as 23 minutes in a tunnel, or just 14 minutes on an elevated viaduct.

The travel-time equation, said Ron Paananen, viaduct project manager, will cause some people to weigh the value they put on their time.

While the elevated options appear to move vehicles faster, the tunnel options could be just as fast if the state can figure out a way to smooth tunnel entries and exits, Paananen said. "The elevated may be the fastest trip, but at what cost?" he asked.

In June, the DOT released eight finalist plans for replacing the viaduct. They include three ideas for surface boulevards, two for aerial viaducts, and three tunnel options.

High costs could eliminate some of the plans. While the state at one time had $2.8 billion available to rebuild the viaduct, it has already spent a large amount of that money to replace the south part of the existing viaduct, and DOT officials said only about $1.5 billion remains.

The DOT plans to release cost estimates for each of the eight viaduct options next week; it's not known whether any could be built with the existing funds. Paananen said the state is now looking at other possible funding sources. The DOT may have to go back to the state Legislature for more money.

Susan Gilmore: 206-464-2054 or sgilmore@seattletimes.com