KING COUNTY – Building a new highway the length of the state along the Cascade foothills is “too long, has too many components and is too complex” to be feasible, according to a report released Oct. 19.

Instead, the highway dubbed the Washington Commerce Corridor might run from Interstate 90 to Chehalis and carry only freight trucks – not passenger cars, consultants recommended in their draft report.

“From this point forward, I will not be looking at anything north of I-90 because the numbers don’t crunch,” said state Sen. Dan Swecker, sponsor of the Commerce Corridor study and a Republican from Lewis County. “The trucking community doesn’t want it.”

The long corridor was envisioned to be financed by a combination of power and fuel utilities, and freight truck, rail and passenger car traffic, and create a possible bypass around Puget Sound traffic.

A conceptual route stretching from Canada to Oregon and bypassing traffic on Interstates 5 and 405 might have cost $41 billion to $50 billion – or $6.7 billion more if 16 miles of tunnels were used to bypass the Mount Baker-Snoqualmie National Forest, the report by Wilbur Smith Associates said.

The idea of running a highway the length of the state along the Cascade foothills prompted opposition from environmentalists and rural towns along the conceptual route.

The consultant’s report confirmed some of the opponents ‘charges: The route is expensive, runs afoul of the state Growth Management Act and faces environmental, funding and routing hurdles.

Utilities weren’t interested in the route, consultants said, because the plan is too far in the future and north-south energy routes are expected to be farther east, if in Washington state at all.

That energy utilities weren’t interested surprised Swecker, who sponsored the $500,000 corridor study ordered by the state Legislature.

“The important thing is that we threw everything into the hopper and gave it a good look and came out with an assessment of options with most potential,” Swecker said.”I’m pleased to know the road itself was possible from the Chehalis area to I-90, which was probably my highest priority.”

The I-90 to Chehalis route is 186 miles.

The route would cost $13.5 billion to $19 billion and might be paid for by high-level tolls on freight trucks – if 50 percent of the truck traffic on Interstate 5 could be tempted to use the alternate route, consultants said.

“This is not a car road,” Swecker said of the recommended trucks-only route. “Adding cars to this road immediately detracts from the attractiveness to trucking, and increased the cost incredibly.”

Public subsidies would still be needed. Land alone from I-90 to Chehalis might cost $3.9-$6.8 billion. Construction could cost $6.4-$15 billion.

Different highway bypasses around Puget Sound traffic have been considered for decades. Interstate 405 was built as the first bypass around Interstate 5.

A route once dubbed Interstate 605 might have replaced 148th Avenue in Bellevue but for local opposition.

Later, I-605 moved east to the Snoqualmie Valley to bypass traffic on I-405. Mercer Island Republican Sen. Jim Horn persuaded the state Legislature to fund a $500,000 study of I-605 in the late 1990s.

The latest highway proposal would have to steer clear of the Cedar River Watershed, which supplies drinking water to about 1.3 million people in the greater Seattle area, consultants said in their report.

The state Growth Management Act pushes growth into urban areas, while the proposed corridor might encourage rural growth, consultants said.

The conceptual route might plow through streams, wetlands and priority habitats, requiring “major environmental mitigation” or not be feasible, consultants said.

The first-ever study was useful because it asked whether private companies might finance an entire highway corridor, said Barbara Ivanov, state director of freight strategy and policy.

That a sweeping, privately funded corridor the length of the state proved infeasible at this time helps focus future evaluation on the segment from I-90 to Chehalis, she said.

A final report and public meetings are expected next month.