A headlamp is a lamp hooked up to the entrance of a car to illuminate the street forward. Headlamps are also usually called headlights, but in the most precise usage, headlamp is the term for the machine itself and headlight is the time period for the beam of mild produced and distributed by the device. Headlamp performance has steadily improved throughout the automobile age, spurred by the great disparity between daytime and nighttime visitors fatalities: the US National Highway Site visitors Security Administration states that almost half of all traffic-related fatalities occur at nighttime, despite solely 25% of visitors travelling throughout darkness. Other vehicles, EcoLight solar bulbs comparable to trains and aircraft, are required to have headlamps. Bicycle headlamps are often used on bicycles, and are required in some jurisdictions. They are often powered by a battery or a small generator like a bottle or hub dynamo. The first horseless carriages used carriage lamps, which proved unsuitable for travel at velocity.

The earliest lights used candles as the commonest type of gasoline. The earliest headlamps, fuelled by combustible gas resembling acetylene gasoline or oil, operated from the late 1880s. Acetylene fuel lamps were widespread 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 light. Quite a few automotive manufacturers supplied Prest-O-Lite calcium carbide acetylene fuel generator cylinder with gas feed pipes for lights as normal equipment for 1904 cars. The primary electric headlamps had been introduced in 1898 on the Columbia Electric Car from the Electric Car Company of Hartford, Connecticut, and had been optional. Two components limited the widespread use of electric headlamps: the short life of filaments in the tough automotive surroundings, and the problem of producing dynamos small sufficient, yet highly effective sufficient to provide enough present. Peerless made electric headlamps commonplace in 1908. A Birmingham, England agency known as Pockley Vehicle Electric Lighting Syndicate marketed the world's first electric automotive-lights as a complete 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 vehicle's Delco electrical ignition and lighting system, forming the modern automobile electrical system. The Information Lamp Firm launched "dipping" (low-beam) headlamps in 1915, however the 1917 Cadillac system allowed the light to be dipped using a lever inside the automotive rather than requiring the driver to stop and get out. The 1924 Bilux bulb was the first trendy unit, having the sunshine for both low (dipped) and EcoLight solutions excessive (important) beams of a headlamp emitting from a single bulb. A similar design was introduced in 1925 by Information Lamp known as the "Duplo". In 1927 the foot-operated dimmer switch or EcoLight solar bulbs dip change was launched and turned commonplace for a lot of the century. 1933-1934 Packards featured tri-beam headlamps, the EcoLight solar bulbs having three filaments. From highest to lowest, EcoLight solutions the beams had been referred to as "country passing", "nation driving" and "metropolis driving". The 1934 Nash also used a three-beam system, though on this case with bulbs of the typical two-filament type, and the intermediate beam combined low beam on the driver's side with excessive beam on the passenger's side, so as to maximise the view of the roadside while minimizing glare toward oncoming visitors.

1952 "Autronic Eye" system automated the choice of high and low beams. Directional lighting, utilizing a swap and electromagnetically shifted reflector to illuminate the curbside solely, was launched within the uncommon, one-yr-solely 1935 Tatra. Steering-linked lighting was featured on the 1947 Tucker Torpedo's middle-mounted headlight and was later popularized by the Citroën DS. This made it potential to turn the light in the path of journey when the steering wheel turned. The standardized 7-inch (178 mm) round sealed-beam headlamp, one per aspect, was required for all automobiles offered within the United States from 1940, nearly freezing usable lighting know-how in place until the 1970s for Americans. In 1957 the legislation changed to allow smaller 5.75-inch (146 mm) spherical sealed beams, two per aspect of the car, and in 1974 rectangular sealed beams have been permitted as effectively. Britain, Australia, and some other Commonwealth countries, as well as Japan and Sweden, also made intensive use of 7-inch sealed beams, although they were not mandated as they had been in the United States.