Toll lanes could avert new I-405 restriction

Within the next few years, Interstate 405's car-pool lanes are going to get so crowded that the restriction will have to be switched from two to three people in a car, state transportation planners have warned.

A proposal being discussed by local leaders could both offer a solution and bring in extra revenue for the state. But it would come at a price.

Under the plan, the diamond lane in each direction would be turned into a "high-occupancy toll" lane, also known as a HOT or "managed" lane. In addition, a second toll lane in each direction would be built along much of the 30-mile corridor. Car-poolers and transit could use the lanes, but they would also be open to lone drivers who would be charged a fee.

"Tolls would allow us to manage the system, auctioning off the excess capacity in the HOT lanes to single drivers," said Craig Stone, I-405 project director for the state Department of Transportation (DOT). "We could carry more vehicles and more people, and we wouldn't have to go to three people in the car-pool lane."

The toll concept, which has been used in other gridlocked regions such as Southern California, has become the anchor of the newest, $4.2 billion plan to improve I-405. Starting with a meeting tomorrow, a committee of local leaders will have about three months to study the proposal and, if they think it would work, get it into a regional transportation funding package voters will consider, possibly as early as this fall.

State planners started looking at toll lanes after voters last fall rejected funding for the previous, $9 billion to $11 billion plan to widen the freeway. Toll lanes, which could help ease congestion for a more affordable price tag, are a direct response to the failure of the Referendum 51 tax package, said Stone.

"People didn't want to pay one way, so they'll have to pay a different way if they want any improvement," he said.

This latest plan for the Eastside's major artery also includes $375 million for bus and arterial improvements and would also add a new general-purpose lane through several sections of the corridor's worst areas — Kirkland, Bellevue and Renton.

If approved and funded, the system could be running in about nine years, Stone said.

State transportation planners have estimated the toll lanes could bring in revenues of about $20 million to $40 million a year. They say the tolls for solo drivers would likely fluctuate with congestion levels. The maximum cost during a peak period in 2020 might be about 40 cents a mile, said Mike Cummings, DOT's environmental and systems director. The preliminary estimates are derived from a formula that takes into account the roadway's congestion level at a given time, its capacity, and drivers' willingness to pay for a faster trip.

A rough design and price tag have already been attached to the proposal, but details, such as whether barriers might separate the HOT lanes from the general roadway, would affect the final cost and complexity of building the project, said King County Councilman Rob McKenna, who sits on the I-405 executive committee.

"The lanes would have to be separated somehow because you don't want people dashing in and out to avoid paying the tolls," he said.

Such issues are to be addressed over the next two months in an $850,000 study of HOT lanes and I-405 that's just getting under way. The funding comes from a Puget Sound Regional Council grant. Officials on the 19-member I-405 executive committee have until June to agree on the final proposal.

"Right now, I doubt we'll be able to make any major decisions until we get some of this information," said Sonny Putter, a city councilman from Newcastle on the I-405 committee.

If voters approve paying for the plan through a regional transportation tax package, the cost would be about $300 a year for average households in King and Snohomish counties with annual incomes between $50,000 and $60,000, according to a recent analysis.

The state Transportation Commission has also ordered a regional HOT lane study, which will examine how tolls on one major corridor could impact traffic flow throughout the Puget Sound region. Tolls are being discussed for other major highways, such as on Highway 520 to fund the construction of a new floating bridge.

Putting HOT lanes on one major corridor but not others would likely cause diversion of traffic onto nontoll roads, Cummings said. Too-high tolls could also cause the idea to backfire.

"If you raise the tolls too high, you could actually lose revenue because people would divert to other facilities. We'd have to strike the appropriate balance," he said.

If the concept proves workable and voters agree to pay for it with new taxes, HOT lanes could bring congestion relief and even help the local economy, McKenna predicted.

"We could guarantee that those HOT lanes remain uncongested," he said. "Imagine if Boeing knew they'd always have an uncongested lane from Renton to Everett, even if it meant they had to pay a little."

Natalie Singer: 206-464-2704 or nsinger@seattletimes.com