OLYMPIA — Commuters using express lanes on I-405 between Lynnwood and Bellevue could see minimum tolls of $1, rising to as much as $15 at peak times, by next spring.

The Washington State Transportation Commission, at the request of the state Legislature, released proposed changes to toll rates on the I-405 toll lanes Wednesday. If approved by the commission in January, it would be the first change to the toll rates there in eight years.

The interstate’s current tolls range from $0.75 and $10. Prices rise when the lanes are close to capacity.

Along with the increased rates, the commission proposed extending the evening tolling time by one hour, until 8 p.m.

The increased tolls would pay for planned construction improvements to I-405. Bids for projects have come in “significantly over cost estimates and planned funding,” requiring more toll revenue, according to the commission.

The Legislature initially allocated $605 million for improvement projects for the interstate. In July, the state awarded the contract to Skanska for $834 million, nearly $230 million over estimates.

Some state legislators are looking for new revenue sources to pay for transportation needs, rather than depending on the state’s gas tax, especially with more drivers using electric and more efficient vehicles.

Boosted tolls aim to increase speeds on express lanes. Increased congestion and on the roads have led the interstate to fall under performance goals. Ninety percent of the time, drivers in the toll lanes are going slower than 45 mph during peak hours, according to the commission.

Longer travel times, the commission reported, can be attributed to populations in nearby areas rising. Lynnwood’s population grew 12% from 2020 to 2022, according to U.S. Census Bureau data.

Drivers using toll lanes pay by mail or by a Good To Go! account with the state Department of Transportation, which lets drivers pay the lowest amount on all toll roads in the state.

These toll increases would also apply to Highway 167, connecting Tacoma and Renton.

The commission will accept written and spoken public comment on the proposed changes until Jan. 22. Written comments can be submitted through the commission’s website. On Jan. 29, they will adopt the final rates.

Changes would take effect March 1.

If the new tolls are implemented, the next phase would measure how much the new fares bring in. Then the commission could adjust things as needed, with the potential for weekend tolling.

Jenelle Baumbach: 360-352-8623; jenelle.baumbach@heraldnet.com; Twitter: @jenelleclar.