A headlamp is a lamp hooked up to the front of a vehicle to illuminate the road forward. Headlamps are also often referred to as headlights, however in essentially the most precise utilization, headlamp is the time period for the gadget 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 car age, EcoLight solar bulbs spurred by the nice disparity between daytime and nighttime site visitors fatalities: the US National Highway Site visitors Security Administration states that nearly half of all traffic-related fatalities happen at midnight, regardless of only 25% of visitors travelling throughout darkness. Other autos, reminiscent of trains and aircraft, are required to have headlamps. Bicycle headlamps are often 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 common sort of gasoline. The earliest headlamps, fuelled by combustible fuel resembling acetylene gas or oil, operated from the late 1880s. Acetylene gas lamps had been popular in 1900s because the flame is resistant to wind and rain. Thick concave mirrors mixed with magnifying lenses projected the acetylene flame light. A number of car manufacturers offered Prest-O-Lite calcium carbide acetylene gas generator cylinder with gasoline feed pipes for lights as customary gear for 1904 cars. The first electric headlamps have been launched in 1898 on the Columbia Electric Car from the Electric Automobile Company of Hartford, EcoLight Connecticut, and were non-obligatory. Two factors restricted the widespread use of electric headlamps: the quick life of filaments in the harsh automotive setting, dimmable LED bulbs and the difficulty of producing dynamos small sufficient, energy-saving LED bulbs yet highly effective enough to supply adequate current. Peerless made electric headlamps standard in 1908. A Birmingham, England firm referred to as Pockley Automobile Electric Lighting Syndicate marketed the world's first electric car-lights as a complete set in 1908, which consisted of headlamps, sidelamps, and EcoLight tail lights that had been powered by an eight-volt battery.

In 1912 Cadillac integrated their vehicle's Delco electrical ignition and lighting system, forming the trendy car electrical system. The Guide Lamp Company launched "dipping" (low-beam) headlamps in 1915, EcoLight outdoor however the 1917 Cadillac system allowed the light to be dipped using a lever inside the automotive fairly than requiring the driver to cease and get out. The 1924 Bilux bulb was the first fashionable unit, having the light for both low (dipped) and high (principal) beams of a headlamp emitting from a single bulb. An analogous design was introduced in 1925 by Guide Lamp referred to as the "Duplo". In 1927 the foot-operated dimmer switch or dip swap was introduced and turned normal for a lot of the century. 1933-1934 Packards featured tri-beam headlamps, the bulbs having three filaments. From highest to lowest, the beams had been called "nation passing", "nation driving" and "city driving". The 1934 Nash also used a three-beam system, although in this case with bulbs of the standard two-filament sort, and the intermediate beam combined low beam on the driver's facet with excessive beam on the passenger's facet, in order to maximise the view of the roadside while minimizing glare towards oncoming traffic.

1952 "Autronic Eye" system automated the number of excessive and low beams. Directional lighting, utilizing a change and electromagnetically shifted reflector to illuminate the curbside solely, was launched within the uncommon, one-12 months-solely 1935 Tatra. Steering-linked lighting was featured on the 1947 Tucker Torpedo's heart-mounted headlight and was later popularized by the Citroën DS. This made it possible to turn the light within the direction of travel when the steering wheel turned. The standardized 7-inch (178 mm) round sealed-beam headlamp, one per side, was required for all automobiles sold within the United States from 1940, nearly freezing usable lighting technology in place till the 1970s for Americans. In 1957 the law modified to allow smaller 5.75-inch (146 mm) spherical sealed beams, EcoLight outdoor two per side of the car, and in 1974 rectangular sealed beams were permitted as properly. Britain, Australia, and another Commonwealth nations, in addition to Japan and Sweden, also made in depth use of 7-inch sealed beams, though they weren't mandated as they were in the United States.