Off-Road Motor Vehicles: Motorized, recreational vehicles used on non-public roads. They include all-terrain vehicles, dirt-bikes, minibikes, motorbikes, trailbikes, and snowmobiles. Excludes MOTORCYCLES, which are considered public road vehicles.Motor Vehicles: AUTOMOBILES, trucks, buses, or similar engine-driven conveyances. (From Random House Unabridged Dictionary, 2d ed)Recreation: Activity engaged in for pleasure.AccidentsAccidents, Traffic: Accidents on streets, roads, and highways involving drivers, passengers, pedestrians, or vehicles. Traffic accidents refer to AUTOMOBILES (passenger cars, buses, and trucks), BICYCLING, and MOTORCYCLES but not OFF-ROAD MOTOR VEHICLES; RAILROADS nor snowmobiles.Athletic Injuries: Injuries incurred during participation in competitive or non-competitive sports.Automobile Driving: The effect of environmental or physiological factors on the driver and driving ability. Included are driving fatigue, and the effect of drugs, disease, and physical disabilities on driving.Motor Neurons: Neurons which activate MUSCLE CELLS.Automobiles: A usually four-wheeled automotive vehicle designed for passenger transportation and commonly propelled by an internal-combustion engine using a volatile fuel. (Webster, 1973)Seat Belts: Restraining belts fastened to the frame of automobiles, aircraft, or other vehicles, and strapped around the person occupying the seat in the car or plane, intended to prevent the person from being thrown forward or out of the vehicle in case of sudden deceleration.