Plan will shift I-90 near pass

SEATTLE – A 15-mile section of Interstate 90 will be shifted farther from the unstable cliffs east of Snoqualmie Pass to better protect drivers from rockslides and snowslides, Transportation Secretary Doug MacDonald said Tuesday.

The $388 million project includes construction of three bridges that would extend out over Keechelus Lake, the reservoir alongside the freeway. Traffic lanes would be 100 feet from the hillside, instead of directly under the most slide-prone areas.

Crews plan to widen one of the nation’s busiest mountain crossings to six lanes from its existing four.

“What we’re proposing is that we move the lanes out over the lake, so the avalanche goes underneath the bridge and into the lake,” project director Brian White said.

Construction on the five-mile stretch is expected to last from 2010 to 2015, with the freeway remaining open to travel.

The bridges will replace some curves so drivers could see farther ahead, and proponents say the design would improve safety for drivers and wildlife such as elk and deer.

The new bridges over the lake and rebuilt bridges that cross creeks would give animals more pathways to the lake, making it less likely they’ll become roadkill. A coalition of environmental groups is helping the agency with the plan.

One planned bridge, across Gold Creek, will be much longer than an existing freeway bridge, allowing better stream flow, White said. In addition, three animal overpasses, with trees and shrubs, will be built across the freeway.

The freeway in that area closes an average of 120 hours a year, mostly to control or clear avalanches. A snow shelter, which covers the westbound lanes, is often overloaded, so the snow slides onto eastbound cars.

Last November, a hillside crumbled in the Keechelus area, dropping rocks as heavy as 5 tons onto the road. Another slide in September, which killed three people, occurred west of the pass.

The money for the project will come from the 9 1/2 -cent gas-tax increase lawmakers approved last year, said DOT spokeswoman Jamie Holter. There isn’t any money yet for another 10-mile widening project east of the lake, but tolls are being studied as one option.

The state Legislature will be asked to look at the possibility of installing tolls on some roadways in the state, including Snoqualmie Pass and the State Highway 520 floating bridge across Lake Washington.

A study by the state Transportation Commission estimates a $4 toll at the pass would raise $513 million for construction, plus $3.1 million for annual maintenance.