California’s Tax on Miles Driven: Pilot, Costs, and Timeline

California does not currently tax drivers on miles driven. The state has researched a per-mile road charge for roughly a decade and most recently ran a Road Charge Collection Pilot from August 2024 through January 2025, but participation was voluntary and no mandatory program exists.¹ A final report to the Legislature is due by December 31, 2026, and the authorizing law sunsets on January 1, 2027, so any permanent per-mile system would require new legislation.² Today, you still pay at the pump, and electric vehicle owners still pay a flat annual fee at registration.

Why the State Is Studying a Per-Mile Charge

California’s gas tax funds most state road maintenance, and the problem the state is trying to solve is straightforward: cars use less fuel than they used to, and electric vehicles use none, so fuel tax revenue falls even as road use holds steady or climbs. A per-mile charge taxes driving itself, which means every vehicle contributes regardless of what powers it. California’s combined taxes and fees on gasoline reached 70.9 cents per gallon as of January 1, 2026, the highest in the country.³ The road charge research is aimed at eventually replacing that revenue stream, not adding to it.

What the Pilot Tested and What It Would Cost

No official per-mile rate has been set. The Legislature would decide that figure if it chose to move forward. The California Road Charge website uses hypothetical rates of 2, 3, and 4 cents per mile in its public calculator and labels them as hypothetical.⁴

The collection pilot ran two study groups to compare approaches. One group paid a flat per-mile rate that was the same for every vehicle. The other paid an individualized rate calculated by dividing the state fuel tax per gallon by the EPA’s estimated fuel economy for that specific vehicle’s make, model, and year.² Under the individualized method, a truck getting 18 miles per gallon pays more per mile than a sedan getting 35.

To put rough numbers on it: California’s gasoline excise tax rose to 61.2 cents per gallon as of July 1, 2025. Divide that by an average fuel economy of about 25 miles per gallon and you get roughly 2.4 cents per mile. A driver covering 12,000 miles a year at that rate would owe about $290. At 3 cents per mile, the same driver would owe $360. These are ballpark estimates, not set rates, and the actual figure would depend on which taxes and fees the Legislature decides the road charge should replace.

Would You Pay More Than You Do Now?

A road charge is not designed to stack on top of the gas tax. SB 339 required pilot participants to receive a credit or refund for the estimated state fuel taxes they already paid at the pump, and extended the same approach to electric vehicle registration fees, with the EV fee credit prorated across the year.² The intent is revenue replacement.

How that plays out depends on your vehicle. A fuel-efficient hybrid that currently generates little gas tax per mile might owe slightly more under a flat road charge. A less efficient truck that currently generates high per-mile fuel tax revenue might break even or come out ahead. Electric vehicles are the clearest case of a new cost.

What Electric Vehicle Owners Pay Today

EV owners in California already pay an annual Road Improvement Fee of $121 for model year 2020 and later zero-emission vehicles, collected at registration renewal.⁵ That flat fee exists because EV drivers do not contribute through the gas tax. Under a future road charge, SB 339 anticipates the fee would be credited against per-mile charges on a prorated basis.² An EV driver covering 12,000 miles a year at a hypothetical 2.4 cents per mile would owe about $290, minus a prorated credit for the $121 already paid, for a net new cost of roughly $170 that year. That is more than the current flat fee, which is exactly the point of switching: a per-mile system charges a high-mileage EV driver more than a low-mileage one, where the flat fee treats them the same.

How Miles Would Be Reported

The collection pilot gave participants three ways to report miles each month.¹

A plug-in device that connects to the OBD-II diagnostic port found under the dashboard in most cars built after 1996. The device records mileage and transmits it wirelessly, and participants could choose whether it used GPS or not.
Vehicle telematics, for newer connected vehicles. This method uses the automaker’s built-in communication system to share mileage directly and requires an active connected-vehicle account.
An odometer photo submitted through the program’s website each month. No hardware or connectivity required.

Privacy drove most of these design choices. SB 1077 directed the advisory committee to weigh protection of personally identifiable information, the ease of re-identifying location data even after personal details are stripped out, and the question of law enforcement access.⁶ The statute also says travel locations or patterns “shall not be reported” and requires legal and technical safeguards for personal information. The non-GPS plug-in and the odometer photo let drivers participate without revealing where they drove. The 2017 pilot reported no data breaches during its run.⁷

What the current law does not do is spell out specific data destruction timelines or set a warrant requirement for law enforcement access. Those are listed as factors for the committee to consider, not as hard rules. A permanent program would almost certainly need more detailed privacy legislation.

Who Was and Was Not Included

SB 339 required participation in the collection pilot to be voluntary for any vehicle group other than state-owned vehicles.² Participants drove gasoline cars, hybrids, and fully electric vehicles. Heavy-duty commercial trucks and motorcycles were not part of either the 2017 pilot or the collection pilot’s primary scope.⁷ The pilot is no longer recruiting, and no public sign-up portal is currently open.

When a Mandatory Program Could Take Effect

There is no set date. The final report under SB 339 is due by December 31, 2026, and the law itself sunsets on January 1, 2027, unless extended.² Converting pilot findings into a mandatory system would require new legislation covering the rate, collection infrastructure, privacy rules, and enforcement. Any permanent rate would be set by the Legislature.⁴ Until that happens, California drivers pay the gas tax at the pump, and EV owners pay the $121 Road Improvement Fee at registration.

1
California Road Charge. Road Charge Collection Pilot
2
LegiScan. California SB 339 2021-2022 Regular Session Chaptered
3
U.S. Energy Information Administration. Many States Slightly Increased Their Taxes and Fees on Gasoline in the Past Year
4
California Road Charge. California Road Charge
5
California DMV. Registration Fees
6
California Legislative Information. California Vehicle Code SB 1077 Chaptered
7
California Department of Transportation. Road Charge Pilot Program Final Report 2017