California public transit agencies soon can adopt stronger "buy America" rules for the content of new bus and rail cars, under a bill signed Monday by Gov. Jerry Brown.

Assembly Bill 1097 permits public transit systems to set their own requirements for the minimum percent of American-made content and components in federally funded buses and rail cars.

Without the state law, the federal minimum of 60 percent applies to public transit purchases of buses and rail cars, legislative staffers say. When the law takes effect Jan. 1, transit agencies can impose a higher buy-American minimum. The buy-America requirements, however, cannot be imposed if they increase the purchase price of vehicles in excess of certain federal thresholds.

"With our economy still feeling the effects of 'the great recession,' we need to keep working to create every job we can," said Assemblywoman Nancy Skinner, D-Berkeley, the author of the bill. "AB 1097 supports American jobs and the recovery of manufacturing at no cost to state or local governments."

The bill has the potential to raise the price of buses and rail cars purchased by public transit systems, according to the Assembly Appropriations Committee.

California lawmakers, however, say they are concerned about the loss of jobs to overseas manufacturers. With a scarcity of American bus and rail car manufacturers, many transit operators buy from overseas companies.

The bill was supported by BART, which plans a $3.4 billion replacement of its entire rail car fleet, and the California Transit Association.