California Air Resources Board

The millions of cars, trucks and motorcycles operating on California's roadways each day are the single greatest source of smog-forming emissions in the state, and a top contributor to climate-changing gases. Ensuring new vehicles are as clean as possible, and keeping existing cars and trucks well maintained and in good working order is vital to reducing transportation pollution. But delivering healthy air to all Californian's requires a move away from combustion powered vehicles and the widespread introduction of zero-emission cars, trucks, and equipment.