Per-mile driving taxes are spreading faster than most Americans realize

DENVER — Automotive analyst Lauren Fix warned listeners of The Kim Monson Show that “about 17 states” are testing or phasing in per-mile driving taxes, a system that charges motorists for every mile they travel rather than taxing them at the fuel pump. The actual scope of the movement is even larger than Fix described. According to Ballotpedia, 37 states have conducted research or joined regional coalitions studying vehicle miles traveled (VMT) taxes, and 24 of those states have either a pilot program or an active program. The Washington State Transportation Commission puts the research figure even higher, at 40 states as of 2024.

The shift is being driven by a simple math problem. The federal gas tax has not been raised since 1993, and as vehicles become more fuel efficient and electric vehicles pay nothing at the pump, the Highway Trust Fund is losing purchasing power. According to the Congressional Research Service, the federal gasoline tax has lost roughly 73 percent of its purchasing power since it was last raised. States are looking for alternatives, and VMT taxes are the leading candidate.

The double taxation question

Fix put the concern plainly: “The people with gasoline and hybrid cars are paying twice. So if I’m filling up at the pump, I’m paying a tax, a federal and a state, and I’m driving on the roads now, I’m paying a mileage tax.”

Every state with an active VMT program has designed its system to prevent exactly that scenario. Oregon’s OReGO program, the nation’s first road usage charge system launched in 2015, charges 2 cents per mile and issues a non-refundable credit for the state’s 40-cent-per-gallon fuel tax paid at the pump. The Washington State Transportation Commission states the principle explicitly: “Drivers would pay RUC or gas tax, but not both.”

But the risk Fix identified is not hypothetical. Colorado illustrates why. Colorado SB21-260, signed in 2021, created a road usage fee assessed per gallon of gasoline and diesel. This fee is layered on top of the existing motor fuel tax, not offered as a replacement. It is being phased in from fiscal year 2022-23 through 2031-32. The Colorado Department of Transportation has also conducted separate VMT pilot programs at a rate of 1.2 cents per mile. For Colorado drivers, the result is additional fees without any offset for what they already pay in fuel taxes.

Which states are furthest along

Four states have enacted VMT programs, according to the Eno Center for Transportation: Oregon (2015), Utah, Virginia, and Hawaii (2023). Outside of Hawaii, none of these programs are mandatory. That will change. Oregon is transitioning to a semi-mandatory system: beginning July 1, 2027, used electric vehicle drivers must choose a flat fee or per-mile payment at registration renewal. New EVs follow on Jan. 1, 2028, and hybrids on July 1, 2028.

Hawaii has the most aggressive timeline. Its HiRUC program will require mandatory participation for EV drivers by July 1, 2028, and for all non-heavy vehicles by 2033. It will be the first state where per-mile charges are compulsory for all drivers.

California, which faces a roughly $215 billion, 10-year transportation funding gap according to the California Road Charge program, ran a six-month pilot from August 2024 through January 2025 under SB 339 at a rate of 2.8 cents per mile. AB 1421, which passed the California Assembly on Jan. 29, 2026, directs continued study with a final report due by Jan. 1, 2027. At the federal level, the Infrastructure Investment and Jobs Act required the Secretary of Transportation to establish a national motor vehicle per-mile user fee pilot program.

Rural drivers and the fairness debate

Fix argued that per-mile taxes hit rural commuters hardest: “Not everybody lives a mile from work. And so if you live out in the country, you’re enjoying life, and then you have to drive to work and it takes you an hour, which isn’t unusual. Then what? Then you’re paying for the mileage driving both directions. And that’s where the problem lies.”

The picture is more complicated than it first appears. The Washington State Transportation Commission found that low-income drivers pay 14 percent more per mile driven under the current gas tax compared to high-income drivers, largely because they tend to drive less fuel-efficient vehicles. A National Bureau of Economic Research working paper reached a similar conclusion, finding that rural areas and central U.S. census tracts would generally pay less under a flat per-mile rate than they currently pay in gas taxes.

The counterpoint is equally valid. Even if the per-mile rate is lower, high-mileage rural drivers would still face a larger total annual bill simply because they drive more. The equity impact depends on whether you measure fairness by the per-mile cost or the total dollars paid each year.

Arizona pushes back

Not every state is moving toward VMT taxes. Arizona placed a constitutional amendment on the November 2026 ballot that would prohibit any state tax or fee based on miles traveled. If approved, Arizona would become the first state to constitutionally ban VMT programs. The measure passed the legislature on party-line Republican votes, signaling that opposition to per-mile taxation is becoming a partisan fault line.