Motorcycles: Two-wheeled, engine-driven vehicles.Head Protective Devices: Personal devices for protection of heads from impact, penetration from falling and flying objects, and from limited electric shock and burn.Accidents, 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.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.Licensure: The legal authority or formal permission from authorities to carry on certain activities which by law or regulation require such permission. It may be applied to licensure of institutions as well as individuals.Insurance: Coverage by contract whereby one part indemnifies or guarantees another against loss by a specified contingency.Legislation as Topic: The enactment of laws and ordinances and their regulation by official organs of a nation, state, or other legislative organization. It refers also to health-related laws and regulations in general or for which there is no specific heading.Wounds and Injuries: Damage inflicted on the body as the direct or indirect result of an external force, with or without disruption of structural continuity.Track and Field: Sports performed on a track, field, or arena and including running events and other competitions, such as the pole vault, shot put, etc.Craniocerebral Trauma: Traumatic injuries involving the cranium and intracranial structures (i.e., BRAIN; CRANIAL NERVES; MENINGES; and other structures). Injuries may be classified by whether or not the skull is penetrated (i.e., penetrating vs. nonpenetrating) or whether there is an associated hemorrhage.Accident Proneness: Tendency toward involvement in accidents. Implies certain personality characteristics which predispose to accidents.Law Enforcement: Organized efforts to insure obedience to the laws of a community.Inflation, Economic: An increase in the volume of money and credit relative to available goods resulting in a substantial and continuing rise in the general price level.Automobile Driver Examination: Government required written and driving test given to individuals prior to obtaining an operator's license.Social Control Policies: Decisions for determining and guiding present and future objectives from among alternatives.Eye Protective Devices: Personal devices for protection of the eyes from impact, flying objects, glare, liquids, or injurious radiation.Motor Vehicles: AUTOMOBILES, trucks, buses, or similar engine-driven conveyances. (From Random House Unabridged Dictionary, 2d ed)Protective Clothing: Clothing designed to protect the individual against possible exposure to known hazards.Safety: Freedom from exposure to danger and protection from the occurrence or risk of injury or loss. It suggests optimal precautions in the workplace, on the street, in the home, etc., and includes personal safety as well as the safety of property.Skull Fractures: Fractures of the skull which may result from penetrating or nonpenetrating head injuries or rarely BONE DISEASES (see also FRACTURES, SPONTANEOUS). Skull fractures may be classified by location (e.g., SKULL FRACTURE, BASILAR), radiographic appearance (e.g., linear), or based upon cranial integrity (e.g., SKULL FRACTURE, DEPRESSED).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.