The California Air Resources Board (CARB) is about to enact a major update to its Advanced Clean Cars (ACC) program, setting new standards on vehicle emissions and zero-emission vehicle regulations that 16 other states follow. Section 177 of the Clean Air Act allows these states to adopt California’s standards in lieu of federal requirements.

The ACC program regulates emissions from light-duty cars and trucks, including both greenhouse gases and smog-forming pollutants. It also sets minimum requirements for sales of zero-emission vehicles in the state, which may be plug-in electric or hydrogen fuel-cell electric vehicles.

The proposed California regulations could influence federal policy as well, said Alice Henderson, director and senior attorney for transportation and clean air policy at the Environmental Defense Fund.