State Moves to Track Your Miles – What You Might Pay

White SUV driving on a sunny road — Photo: Jenson / Shutterstock

California already tested technology that tracks how many miles you drive, not how much gas you buy, to figure out how to charge you for using the roads.

Quick Take

California ran a Road Charge Collection Pilot from August 2024 to January 2025, testing per-mile payment methods as a possible gas tax replacement.
A new bill, Assembly Bill (AB) 1421, would require state agencies to combine their research and report recommendations to lawmakers by January 1, 2027.
No statewide mileage tax rate, start date, or payment rule has been set in any official bill or Caltrans document.
The idea has become a flashpoint in the California governor’s race, with one candidate saying “everything should be on the table” while denying he proposed a new tax.

What California Has Actually Tested So Far

The California Department of Transportation, known as Caltrans, ran a real pilot program testing whether charging drivers by the mile could replace the state’s gas tax. The program, authorized under Senate Bill 339, collected data from August 2024 through January 2025. A final report on what worked and what didn’t is due to the Legislature by December 2026.

Two Different Ways To Charge Drivers

The pilot didn’t test just one pricing idea. According to a California Transportation Commission presentation, one group of drivers paid a flat fee for every mile driven. A second group paid a fee tied to their specific vehicle, calculated by taking the state’s per-gallon gas tax and dividing it by that car’s fuel-economy rating. That split matters, because a fuel-efficient car and a gas-guzzler would pay very differently under the second model.

The legal vehicle moving this forward right now is AB 1421, introduced by Assembly Member Lori Wilson in February 2025. The bill does not create a tax. It requires state agencies to pull together existing research on mileage-based fees and report formal recommendations to legislative committees by January 1, 2027. It also keeps alive an existing Road Usage Charge Technical Advisory Committee, meaning this work has been building for years, not appearing suddenly.

Why California Is Even Looking At This

Gas tax revenue pays for road repairs, but that money is shrinking. Cars get better gas mileage, and more drivers own hybrids or fully electric vehicles that use little or no gasoline. The Congressional Budget Office has projected that if electric vehicles made up half of new car sales between 2028 and 2031, the federal Highway Trust Fund would take a major revenue hit. Caltrans defines a road charge simply as paying based on miles driven instead of gallons purchased.

What The Research Does Not Settle

Here is where the official record stops short of the loudest claims circulating online. Neither the AB 1421 bill text nor Caltrans’s program pages set a statewide per-mile rate, a start date, or a mandatory payment system. The documents describe research, pilots, and a committee, not an enacted tax. How a future program would treat the existing gas tax, whether as a replacement, an offset, or something charged on top of it, has not been decided in the materials reviewed.

How This Became A Campaign Issue

The mileage tax idea surfaced in California’s governor’s race. Candidate Xavier Becerra said “everything should be on the table” when asked about funding road repairs, while his campaign stated he has not proposed a mileage tax. Rival candidate Steve Hilton has opposed the idea outright. That gap between openness to studying an option and actually adopting one is where much of the public confusion has taken root.

@XavierBecerra
You said that California needs the money for road repairs, the current gas tax is about $37 million a day, what did you do with the money.
No mileage tax.
NO NEW TAXES pic.twitter.com/3izyRzBVwz

— B Rad (@jsbees) October 31, 2026

California is not alone in wrestling with this. States including Utah, Oregon, Virginia, and Hawaii have tried road usage charging systems with mixed results, and a Reason Foundation study found none of the four permanent programs it evaluated matched the gas tax’s low administrative costs. That track record suggests California’s technical advisory committee has real work ahead before any statewide rollout could function smoothly, let alone fairly, for drivers across rural, suburban, and urban areas.

What remains unresolved is just as telling as what’s been tested. Privacy protections for mileage tracking, enforcement penalties, and household cost impacts are not finalized in any public document. Until the pilot’s full report lands in December 2026 and AB 1421’s recommendations follow by January 2027, drivers are left watching a research process that is real, active, and unfinished.