A California bill that would require new vehicles to have what’s known as passive speed limiters, or warning signals when the vehicle exceeds posted speed limits, passed one house of the state legislature.

The state senate bill, introduced by Sen. Scott Wiener, D-San Francisco, passed the senate chamber on May 21 by a vote of 22 to 13. If passed by the state assembly and signed by the governor, it would require that all new passenger cars, trucks and buses made or sold in California be equipped with the speed limiters starting in 2032, including a 50% phase-in by 2029.

The technology is also known variously as a passive speed governor and passive Intelligent Speed Assistance, or ISA. Passive is the key word in the term, meaning the devices don’t actually limit vehicle speed but instead warn the driver if he or she exceeds a speed limit by a certain number of mph. Senate Bill 961 would require audible and visual warnings if a vehicle exceeds a posted speed limit by more than 10 mph.

Wiener, in announcing senate passage of the bill, said in a press release that it follows a recommendation by the National Transportation Safety Board to require such technology in new vehicles. He pointed to research that shows speeding dramatically increases the chance of a fatal crash, including a 2023 state Office of Traffic Safety report that a third of traffic California fatalities from 2017 to 2021 involved speed and indicating a 23% increase in speed-related crashes from 2019 to 2022.

The assembly must pass its version of the bill by Aug. 31 if it’s to advance this session.

As is the case with many legislative firsts, California regulatory moves tend to influence other states, causing a ripple effect throughout much of the country, so the action, if it becomes law, could ultimately make such speed-dampening technology standard in the industry.

The European Union will require the technology in vehicles sold there starting this July.

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