Electric vehicles will be introduced into the Los Angeles area to reduce air pollution. Currently proposed battery-powered electric vehicles are expensive to operate and have limited range and power. A grid system of overhead wires to power electric vehicles while on the main roads offers savings in battery-depreciation costs, together with greater vehicle range and power. We estimate the annual cost of the grid-battery system and compare it to the battery-only system. Air-pollution impacts of the two systems are also compared. With a sufficiently large number of electric vehicles, the grid system yields significant cost reductions and provides better service to vehicle users while offering air-pollution reduction advantages.