If Washington wants to shift from taxing drivers per gallon of gas to charging per mile they drive, lawmakers should make the change slowly and consider starting with electric cars, state transportation officials agreed Tuesday.

The Washington State Transportation Commission approved a set of recommendations to the state Legislature outlining broad ideas about how Washington could move from the gas tax to a per-mile fee known as a road usage charge.

Any widespread adoption of such a tax is likely years away. But Tuesday’s vote takes the idea one step closer to formal consideration in Olympia and offers a preview of debates likely to play out around the tax. Particularly acute in an era of climate crisis: Should money from the tax be spent on roads alone?

Traffic Lab is a Seattle Times project that digs into the region’s thorny transportation issues, spotlights promising approaches to easing gridlock, and helps readers find the best ways to get around. It is funded with the help of community sponsors Madrona Venture Group and PEMCO Mutual Insurance Company. Seattle Times editors and reporters operate independently of our funders and maintain editorial control over Traffic Lab content.

Discussion of a per-mile tax has been underway for years as vehicles get more fuel-efficient and more drivers switch to electric cars. In coming years, the state expects gas-tax revenues to increase at a significantly slower rate than road construction costs.

Oregon already has an optional per-mile tax, and Utah plans to offer electric- and hybrid-vehicle owners the option to pay a similar charge instead of annual fees next year. Washington charges electric and hybrid-car owners annual fees.

Commission members emphasize that a per-mile tax in Washington is meant to be a replacement for the gas tax, not an additional tax. State lawmakers will ultimately decide whether to create the charge. Because of bonds already issued against gas-tax dollars, privacy questions and other concerns, a full transition away from the gas tax would likely take 10 years or longer.


The commission recommended that revenue from the tax be restricted under a state constitutional amendment that today requires gas-tax money be spent “exclusively for highway purposes.”

That drew blowback from environmental groups, the Seattle Department of Transportation and King County Councilmember Claudia Balducci.

“It’s fundamentally backward-looking,” Balducci said. Rural areas, suburbs and urban areas like Seattle and Bellevue have different transportation needs, Balducci said.

“You could pour road money down on downtown Bellevue and it just wouldn’t do any good,” Balducci said. “Same for downtown Seattle. The funding that the state makes available should be flexible.”

Transportation Choices Coalition and other groups also argue a per-mile charge should be structured as a progressive tax that doesn’t unfairly burden people with low incomes.

Conservative groups raised concerns about using taxes paid by drivers to fund transit or other efforts.


Mariya Frost, transportation director at the Washington Policy Center, said that could turn the tax into “a tool that can punish people for how they drive or be used to discourage people from driving.”

“I cannot see this tool being used appropriately in Washington state — or fairly,” Frost said.

Transportation Commission member Hester Serebrin, who is also policy director at the Transportation Choices Coalition, opposed the recommendation to restrict the spending to highway uses. Biking, walking and transit help “take cars off the road,” Serebrin said.

Most other members backed the restriction, saying their mandate was to find a way to replace the gas tax.

Last year, the state tested a per-mile tax with a pilot project in which about 2,000 volunteers tracked miles driven and were charged a mock 2.4-cent-per-mile tax. The Transportation Commission says that charge is about what the owner of an average car in Washington pays per mile under today’s 49.4-cent-per gallon state gas tax.

How miles are tracked will be another key issue as Washington debates a per-mile tax. The pilot program allowed drivers to use various ways of tracking miles, including odometer readings and GPS devices. GPS devices can deduct miles driven outside Washington, but are likely to raise significant privacy and data collection questions.

In a survey of participants in the test, nearly half of those who responded grew more supportive of a per-mile charge after testing it, according to the Transportation Commission. On a list of potential concerns, privacy was at the top.

The Transportation Commission plans to deliver a final report to the Legislature in January.