California Governor Gavin Newsom vetoed a bill that would require human drivers to be on board self-driving trucks, the Associated Press reports. Union leaders and truck drivers said that this measure would save hundreds of thousands of jobs in the state.

Assembly Bill 316 required that a trained human driver be present in self-driving vehicles weighing over 10,001 pounds. In a report by Reuters, the bill was passed by a “heavy majority” in both state legislature houses.

Currently, California bans autonomous trucks of that weight. Bill 316 arose from efforts to develop a regulatory framework to lift that restriction, reported Reuters.

In his veto message, Newsom stated that due to “the existing regulatory framework that presently and sufficiently governs this particular technology, this bill is not needed at this time.”

Newsom pointed to 2012 legislation that allows the state Department of Motor Vehicles to work with the California Highway Patrol, the National Highway Traffic Safety Administration “and others with relevant expertise to determine the regulations necessary for the safe operation of autonomous vehicles on public roads.”

The head of the California Labor Federation, Lorena Gonzalez Fletcher, called Newsom’s veto shocking and estimated that removing drivers would cost a quarter million jobs in the state, according to AP.

Currently, there is a national shortage of truck drivers disrupting the supply chain. Between self-driving trucks and the gig economy, the trucking industry is exploring how to keep driving the economy.