In order to be arrested and convicted of a DUI, the individual must be driving a vehicle. The California Vehicle Code defines vehicle as "a device by which any person or property may be propelled, moved, or drawn upon a highway, excepting a device moved exclusively by human power or used exclusively upon stationary rails or tracks." Automobiles, trucks, motorcycles, mopeds, and snowmobiles fall within the classification of a vehicle.

For the purposes of a DUI arrest and conviction, other type of “vehicles" include bicycles; boats, aquaplanes, and water skis; aircraft; and horses and other beasts of burden. However, wheelchairs and motorized tricycles and quadricycles, operated by persons who, because of physical disability, are otherwise unable to move about as pedestrians, may not be prosecuted for DUI.