California Gov. Gavin Newsom vetoed a bill Sept. 27 that would have added people using autopilot features in their cars after drinking or consuming drugs to the state’s driving under the influence law.

The legislation would have redefined the term “drive” for certain driving under the influence, reckless driving, and vehicular manslaughter criminal offenses when a car is operating with autonomous technology—such as Tesla Autopilot.

The term would have included the “volitional movement of a vehicle with driver support features engaged that require a person to supervise the vehicle in order to steer, brake, or accelerate, as needed to maintain safety.”

The governor vetoed Assembly Bill 2502 (AB 2502) and recommended that lawmakers revisit the issue next year.

Newsom gave several reasons for declining to sign the bill.

“I share the author’s goal of ensuring that drivers cannot avoid responsibility for impaired driving by engaging partially automated technology,” Newsom said in the veto message.

“Unfortunately, this bill as drafted introduces significant uncertainties into DUI law, which could have the unintended consequence of making it more difficult to hold dangerous drivers accountable,” the governor said.

The governor said by using undefined terms that are not in alignment with established standards, such as using “driver support features,” as a term, the bill could leave police officers, prosecutors, and courts to resolve complex questions about a vehicle’s software and capabilities before determining if an impaired person was legally driving.

The bill’s author, Democratic Assemblywoman Gail Pellerin of Santa Cruz, created the bill after a Tesla driver in San Francisco passed out on the Bay Bridge in 2018 with a blood alcohol level of more than twice the legal limit, she wrote in a statement to the legislature.

When the driver awoke, he argued that he wasn’t driving drunk because the car was on autopilot, she said.

“These incidents are occurring more often and stem from consumers being misled into believing that it is acceptable to drive a semi-autonomous vehicle while impaired as long as the ‘autopilot’ system is engaged,” Pellirin added.

“This confusion is worsened by companies using misleading language in advertising and exaggerating their vehicles’ capabilities, leading consumers to believe the vehicles are fully self-driving.”

California State Assemblywoman Gail Pellerin (D-Santa Cruz) on the Assembly floor in Sacramento on April 27, 2023. (Courtesy of Assemblywoman Gail Pellerin's Office)

The Automobile Club of Southern California and AAA Northern California, Nevada and Utah clubs supported the measure, saying it closed a gap in DUI enforcement and prevented the misuse of partially automated systems.

Although Pellerin does not name Tesla in the legislation, the company and its CEO Elon Musk have disputed California’s accusations of misleading advertising claims about Tesla Autopilot, arguing in court filings that their statements were not misleading and were legally protected speech.

Pellerin didn’t return a request for comment about the veto by the time of publication.