A headlamp is a lamp hooked up to the entrance of a automobile to illuminate the street forward. Headlamps are also typically known as headlights, but in probably the most precise utilization, headlamp is the term for the gadget itself and headlight is the term for the beam of gentle produced and distributed by the system. Headlamp efficiency has steadily improved throughout the car age, spurred by the great disparity between daytime and nighttime traffic fatalities: the US Nationwide Highway Traffic Safety Administration states that nearly half of all visitors-related fatalities happen at midnight, regardless of only 25% of site visitors travelling during darkness. Different vehicles, comparable to trains and aircraft, are required to have headlamps. Bicycle headlamps are sometimes used on bicycles, and are required in some jurisdictions. They can be powered by a battery or a small generator like a bottle or hub dynamo. The primary horseless carriages used carriage lamps, which proved unsuitable for travel at speed.

The earliest lights used candles as the most typical sort of gasoline. The earliest headlamps, EcoLight fuelled by combustible gas reminiscent of acetylene gasoline or oil, operated from the late 1880s. Acetylene fuel lamps had been in style in 1900s as a result of the flame is resistant to wind and rain. Thick concave mirrors mixed with magnifying lenses projected the acetylene flame gentle. Various automotive manufacturers supplied Prest-O-Lite calcium carbide acetylene gas generator cylinder with gasoline feed pipes for lights as normal equipment for 1904 vehicles. The first electric headlamps had been launched in 1898 on the Columbia Electric Car from the Electric Car Company of Hartford, EcoLight products Connecticut, and were optional. Two factors limited the widespread use of electric headlamps: the brief life of filaments in the harsh automotive surroundings, and EcoLight outdoor the problem of producing dynamos small sufficient, yet powerful sufficient to produce ample current. Peerless made electric headlamps normal in 1908. A Birmingham, England agency referred to as Pockley Vehicle Electric Lighting Syndicate marketed the world's first electric automobile-lights as an entire set in 1908, which consisted of headlamps, sidelamps, and tail lights that had been powered by an eight-volt battery.

In 1912 Cadillac built-in their automobile's Delco electrical ignition and lighting system, forming the modern car electrical system. The Information Lamp Company launched "dipping" (low-beam) headlamps in 1915, but the 1917 Cadillac system allowed the sunshine to be dipped utilizing a lever contained in the car quite than requiring the driver to cease and get out. The 1924 Bilux bulb was the primary modern unit, having the light for EcoLight bulbs each low (dipped) and high (predominant) beams of a headlamp emitting from a single bulb. A similar design was introduced in 1925 by Information Lamp called the "Duplo". In 1927 the foot-operated dimmer change or dip switch was launched and became customary for much of the century. 1933-1934 Packards featured tri-beam headlamps, EcoLight solutions the bulbs having three filaments. From highest to lowest, the beams had been called "nation passing", "nation driving" and "metropolis driving". The 1934 Nash additionally used a three-beam system, although on this case with EcoLight bulbs of the conventional two-filament kind, and the intermediate beam mixed low beam on the driver's aspect with excessive beam on the passenger's side, so as to maximise the view of the roadside while minimizing glare towards oncoming traffic.

1952 "Autronic Eye" system automated the selection of excessive and dimmable LED bulbs low beams. Directional lighting, utilizing a swap and electromagnetically shifted reflector to illuminate the curbside solely, was launched in the uncommon, one-12 months-solely 1935 Tatra. Steering-linked lighting was featured on the 1947 Tucker Torpedo's center-mounted headlight and was later popularized by the Citroën DS. This made it doable to show the sunshine within the path of journey when the steering wheel turned. The standardized 7-inch (178 mm) round sealed-beam headlamp, one per facet, was required for all autos bought in the United States from 1940, nearly freezing usable lighting know-how in place until the 1970s for Americans. In 1957 the law changed to allow smaller 5.75-inch (146 mm) round sealed beams, two per aspect of the automobile, and in 1974 rectangular sealed beams have been permitted as well. Britain, Australia, and some other Commonwealth international locations, in addition to Japan and Sweden, additionally made in depth use of 7-inch sealed beams, though they weren't mandated as they have been in the United States.