California's Zero Emission Vechile program requires automakers to offer vehicles for slae that produce no emisssions starting in 2003. This study examines the costs and emission benefits of technologies that may be used to meet program requirements, including battery-powered electric vehilces, direct hydrogen fuel-cell vehicles, and gasoline hybird electric vechiles. The authors conclude California should eliminate the program, tighten emission standards on light-duty vehicles, and focus on setting emission performance performance standards.