California motorists could one day pay a new road charge based on every mile they drive. The system, however, might be designed to calculate mileage without tracking a driver’s location.
The issue returned to the spotlight this week after gubernatorial candidate Xavier Becerra declined to rule out a mileage-based tax. In an interview, he said “everything was on the table.”
Becerra’s campaign later said he had not put forward a mileage-tax proposal. Still, his remarks left millions of California drivers wondering how Sacramento would measure their mileage — and whether participation would require the state to monitor where they go.
A six-month California pilot project provides an early look at the possible options. Those methods ranged from GPS-enabled devices that record vehicle data to the much simpler approach of submitting a photograph of a car’s odometer.
Caltrans conducted the pilot from August 2024 through January 2025, with 800 participants testing four different methods for reporting how far they drove.
Participants could connect a GPS-equipped device to their vehicles, use a device without GPS, permit their cars’ built-in systems to transmit mileage information or upload odometer photographs.
Sharing location data was optional. That meant drivers could take part without providing a detailed record of their routes or destinations.
GPS devices were selected by roughly 34% of participants, while another 30% chose to submit odometer photos. The rest relied on their vehicles’ onboard systems or devices that did not use GPS.
YOU MIGHT ALSO LIKE: California Woman Accused of Killing Trans Son-in-Law Blames Husband
The pilot also examined how a mileage-based road charge might affect drivers’ budgets.
Half of the participants paid a flat rate of 2.8 cents per mile. At 10,000 miles, that would amount to $280 before credits. The other half were assigned rates tailored to their vehicles’ federally rated fuel efficiency.
Participants received monthly charges, along with credits or refunds for state gasoline taxes or the electric-vehicle Road Improvement Fee they had already paid during the trial.
The pilot was created under Senate Bill 339, introduced by state Sen. Scott Wiener (D-San Francisco) and signed by Gov. Gavin Newsom in September 2021. The law ordered California to explore mileage-based road charges as declining gas-tax revenue threatens a traditional source of transportation funding.
Even though no statewide program has been approved, the prospect of another charge on drivers has quickly become a political flashpoint.
Republican gubernatorial challenger Steve Hilton has promised to veto a mileage tax if voters elect him.
“They never stop gouging you,” Hilton told The California Post.
Assembly Republican leader Alexandra Macedo likewise criticized the proposal, saying a mileage charge would place an especially heavy burden on working Californians.
“They say they want to tax billionaires and then they’re talking about a mileage tax that hits the working class the hardest,” she told The Post.
For now, California has not approved a statewide mileage tax.