Automotive lighting

Early road vehicles used fuelled lamps before the availability of electric lighting. The first Ford Model T used carbide lamps for headlights and oil lamps for tail lights. It did not have all-electric lighting as a standard feature until several years after its introduction. Dynamos for automobile headlights were first fitted around 1908 and became commonplace in 1920s automobiles. Trafficators—signalling arms that flipped up, which later were lighted—were introduced in the early 1900s, and were actuated either mechanically or pneumatically. Tail lights and brake lights were introduced around 1915, and by 1919, low-beam or dipped beam headlights were available. Sealed beam headlights were introduced in 1936 and standardized as the only acceptable type in the US in 1940. Self-cancelling turn signals were developed in 1940. By 1945, headlights and signal lights were integrated into the body styling. Halogen headlights were developed in Europe in 1960. High-intensity discharge (HID) headlights were produced starting in 1991. In 1993, the first LED tail lights were installed on mass-production automobiles, with LED headlights subsequently being introduced in the 2000s as more powerful LEDs became available. ==Colour of light emitted==

The colour of light emitted by vehicle lights is largely standardized by established conventions, first codified in the 1949 Geneva Convention on Road Traffic and later specified in the 1968 United Nations Vienna Convention on Road Traffic. With some regional exceptions, lights facing rearward must emit red light, side-facing lights and all turn signals must emit amber light, and lights facing forward must emit white or selective yellow light. No other colours are permitted except on emergency vehicles. Vehicle lighting colour specifications can differ somewhat in countries that have not signed the 1949 and/or 1968 Conventions; examples include turn signals and side marker lights in North America, as described in those lights' sections later in this article. ==Forward illumination==

Forward illumination is provided by high- ("main", "full", "driving") and low- ("dip", "dipped", "passing") beam headlights, which may be augmented by auxiliary fog lights, driving lights, or cornering lights. Headlights Low beam (dipped beam, passing beam, meeting beam) standards instead of UN ECE regulations. These standards contain regulations for dipped beam headlights that also specify a beam with a sharp, asymmetric cut-off; the half of the beam closest to oncoming drivers is also flat and low, but not as low as prescribed in UN ECE regulations. The half of the beam closest to the outside of the road is also flat, but higher than the half closest to oncoming vehicles. This results in substantially increased glare for oncoming drivers and also poorer illumination of the near side of the roadway in comparison to headlights conforming to UN ECE regulations. High beam (main beam, driving beam, full beam) Auxiliary high beam lights may be fitted to provide high-intensity light to enable the driver to see at longer range than the vehicle's high beam headlights. Such lights are most notably fitted on rally cars, and are occasionally fitted to production vehicles derived from or imitating such cars. They are common in countries with large stretches of unlit roads, or in regions such as the Nordic countries that receive fewer daylight hours during winter. "Driving light" is a term hailing from the early days of night time driving, when it was relatively rare to encounter an opposing vehicle. Only on occasions when opposing drivers passed each other would the low (dipped or "passing") beam be used. The high beam was therefore known as the "driving beam", and this terminology is still found in international UN Regulations, which do not distinguish between a vehicle's primary (mandatory) and auxiliary (optional) upper/driving beam lights. The "driving light" term has been supplanted in US regulations by the functionally descriptive term "auxiliary high-beam light". Many countries regulate the installation and use of driving lights. For example, in Russia, each vehicle may have no more than three pairs of driving lights (including the original lights), and in Paraguay, auxiliary driving lights must be off and covered with opaque material when the vehicle is operated in urban areas. Front fog lights or selective yellow light, and were designed for use at low speed to increase the illumination directed towards the road surface and verges in conditions of poor visibility due to fog, dust or snow. They are sometimes used in place of dipped-beam headlights, reducing glare from fog or falling snow, although the legality of using front fog lights without low-beam headlights varies by jurisdiction. fog lights In most countries, weather conditions rarely necessitate the use of front fog lights and there is no legal requirement for them, so their primary purpose is frequently cosmetic. They are often available as optional extras or only on higher trim levels of many cars. Since as early as the 2020s, several car manufacturers have noticeably omitted the front fog lights from many of their latest models, as more recent high-tech lighting technologies such as daytime running lamps (DRLs) and LEDs connected to automatic high-beam systems negate the use of fog lights. However, some manufacturers who still offer fog lights as standard equipment in certain model trims have diversified its use to function also as an automatic lighting delay for vehicles, to light up surroundings and roadside curbs after being parked. An SAE study has shown that in the United States, more people inappropriately use their fog lights in dry weather than use them properly in poor weather. Because of this, use of the fog lights when visibility is not seriously reduced is often prohibited in most jurisdictions; for example, in Australia, "The driver of a vehicle must not use any fog light fitted to the vehicle unless the driver is driving in fog, mist or under other atmospheric conditions that restrict visibility." The respective purposes of front fog lights and driving lights are often confused, due in part to the misconception that fog lights are always selective yellow, while any auxiliary light that makes white light is a driving light. Automakers and aftermarket parts and accessories suppliers frequently refer interchangeably to "fog lights" and "driving lights" (or "fog/driving lights"). Cornering lights On some models, cornering lights provide steady-intensity white light for lateral illumination in the direction of an intended turn or lane change. They are generally actuated in conjunction with the turn signals, and they may be wired to also illuminate when the vehicle is shifted into reverse gear. as well as rear cornering lights. Cornering lights have traditionally been prohibited under international UN Regulations, though provisions have recently been made to allow them as long as they are only operable when the vehicle is travelling at less than 40 kilometres per hour (about 25 mph). Spotlights Police cars, emergency vehicles, and vehicles competing in road rallies are sometimes equipped with an auxiliary spotlight, sometimes called an "alley light", in a swivel-mounted housing attached to one or both A-pillars, aimed by a handle protruding through the pillar into the vehicle. ==Conspicuity, signal and identification lights==

Conspicuity devices are lights and reflectors that are intended to make a vehicle more conspicuous and visible with respect to its presence, position, direction of travel, change in direction, or deceleration. Such lights may light steadily, blink, or flash, depending on their intended and regulated function. Most must be fitted in pairs—one left and one right—though some vehicles have multiple pairs (such as two left and two right stop lights) and/or redundant light sources (such as one left and one right stop light, each containing two bulbs). Front SE Front position lights lights rather than the vehicle's headlights. In Germany, the StVZO (Road Traffic Licensing Regulations) calls for a different function provided by these lights: with the vehicle's ignition switched off, the operator may activate a low-intensity white light at the front and red light at the rear on either the left or right side. This function is used when parking in narrow unlit streets to provide parked-vehicle conspicuity to approaching drivers. This function, which is optional under UN and US regulations, is served passively in the United States by mandatory side marker retroreflectors. Functional piggybacking, such as using the headlights, front turn signals, or fog lights as DRLs, is not permitted; the EU Directive requires functionally specific daytime running lights compliant with UN Regulation 87 and mounted to the vehicle in accord with UN Regulation 48. Prior to the DRL mandate, countries requiring daytime lights permitted low beam headlights to provide that function. National regulations in Canada, Sweden, Norway, Slovenia, Finland, Iceland, and Denmark require hardwired automatic DRL systems of varying specification. DRLs are permitted in many countries where they are not required, but prohibited in other countries not requiring them. In the US, daytime running lights may emit either amber or white light, and may produce up to 7,000 candela. This has provoked a large number of complaints about glare. Dim-dip lights UK regulations briefly required vehicles first used on or after 1 April 1987 to be equipped with a "dim-dip" device or special low-intensity running lights, except such vehicles as complying fully with UN Regulation 48 regarding the installation of lighting equipment. A dim-dip device operates the dipped beam headlights at between 10% and 20% of normal low-beam intensity. Running lights permitted as an alternative to dim-dip were required to emit at least 200 candela straight ahead, and no more than 800 candela in any direction. In practice, most vehicles were equipped with the dim-dip option rather than dedicated running lights. In 1988, the European Commission successfully prosecuted the UK government in the European Court of Justice, arguing that the UK requirement for dim-dip was illegal under EC directives prohibiting member states from enacting vehicle lighting requirements not contained in pan-European EC directives. As a result, the UK requirement for dim-dip was quashed. These side-facing devices make the vehicle's presence, position and direction of travel clearly visible from oblique angles. Side markers are permitted but not required on cars and light passenger vehicles outside the United States and Canada. If installed, they are required to be brighter and visible through a larger horizontal angle than US side markers, may flash only in synchronous phase with the turn signals (but are not required to flash), and they must be amber at the front and rear, except rear side markers may be red if they are grouped, combined, or reciprocally incorporated with another rear lighting function that is required to be red. (intended for showing the overall length of long vehicles from in front and behind a combination) and the U.S. type amber front/red rear lights for passenger cars. Side marker lights can be seen as the successor to "cowl lights" used on vehicles during the 1920s to 1930s, which were a pair of small lights installed at the top edges of the cowl between the hood and the windshield, and would serve as a reference point for oncoming traffic where the widest part of the body was. These were sometimes used in tandem with fender lights during the same time period, when fenders were separate from the body and only covered the wheels. Turn signals Direction indicator lights). They are activated by the driver on one side of the vehicle at a time to advertise intent to turn or change lanes towards that side, or used simultaneously as a hazard warning signal to warn other drivers of a vehicle parked on the road which was previously made by a relay or the leaf spring in a thermal flasher. If the stalk switch is not moved beyond the fixed left/right position and allowed to flip back, the control module will only flash the lights three times. History of turn signals Electric turn signal lights date from as early as 1907. In 1908, Alfredo Barrachini in Rome added electric lights inside the arms that turned on as they extended, but operation was still by a cable system. An early patent for a new style of turn signal was issued in 1909 to a British man named Percy Douglas-Hamilton, who came up with a system that used a hand on each side of the car, which could be illuminated to indicate a coming turn. Silent film star Florence Lawrence is also credited with introducing an innovative version of the signalling arm in 1914, a predecessor to the modern turn signal, and a mechanical brake signal. She did not patent these inventions, however, and received no credit or profit from them. Possibly the first factory installation of illuminated turn signals was on the Talbot 105 (as well as the 75 and 95), which used them at the front as well as at the rear from 1932 until 1935. The modern flashing turn signal was patented in 1938, and shortly after, most major automobile manufacturers offered this optional feature before it became mandatory in 1967. After turn signals were introduced regulations were brought in requiring them and laying out specifications that had to be met. Ultimately standards governed minimum and maximum permissible intensity levels, minimum horizontal and vertical angles of visibility, and minimum illuminated surface area, to ensure that they are visible at all relevant angles, do not dazzle those who view them, and are suitably conspicuous in all conditions ranging from full darkness to full direct sunlight. Electrical connection and switching Turn signals are required to blink on and off, or "flash", at a steady rate of between 60 and 120 pulses per minute (1–2 Hz). The international UN Regulations do not include analogous specifications. Virtually all vehicles (except many motorcycles and commercial semi-tractors) have a turn indicator self-cancelling feature that returns the lever to the neutral (no signal) position as the steering wheel approaches the straight-ahead position after a turn has been made. Beginning in the late 1960s, using the direction-indicator lights to signal for a lane change was facilitated by the addition of a spring-loaded momentary signal-on position just shy of the left and right detents. The signal operates for however long the driver holds the lever partway towards the left or right turn signal detent. Some vehicles have an automatic lane-change indication feature; tapping the lever partway towards the left or right signal position and immediately releasing it causes the applicable turn indicators to flash three to five times. Some transit buses, such as those in New York, have turn signals activated by floor-mounted momentary-contact footswitches on the floor near the driver's left foot (on left-hand drive buses). The foot-activated signals allow bus drivers to keep both hands on the steering wheel while watching the road and scanning for passengers as they approach a bus stop. New York City Transit bus drivers, among others, are trained to step continuously on the right directional switch while servicing a bus stop, to signal other road users they are intentionally dwelling at the stop, allowing following buses to skip that stop. This method of signalling requires no special arrangements for self-cancellation or passing. Sequential turn signals Sequential turn signals are a feature on some cars, wherein the turn signal function is provided by multiple lit elements that illuminate sequentially rather than simultaneously. The visual effect is one of outward motion in the direction of the intended turn or lane change. Sequential turn signals were factory fitted to 1965–1971-model Ford Thunderbirds, 1967–1973 Mercury Cougars, Shelby Mustangs between 1967 and 1970, 1969 Imperials, the Japanese-market 1971–1972 Nissan Cedric, Nissan Laurel and Nissan Bluebird, some Volkswagen, Audi, SEAT, Škoda and Porsche models, Toyota C-HR, some Peugeots and Ford Mustangs since 2010. Two different systems were employed. The earlier, fitted to the 1965 through 1968 Ford-built cars and the 1971–1972 Nissan Cedric, employed an electric motor driving, through reduction gearing, a set of three slow-turning cams. These cams would actuate switches to turn on the lights in sequence. Later Ford cars and the 1969 Imperial used a transistorised control module with no moving parts to wear, break, or go out of adjustment. FMVSS 108 has been officially interpreted as requiring all light sources in an active turn signal to illuminate simultaneously. Some vehicles, such as the 2010 and later Ford Mustang, Other US vehicles with sequential turn signals comply by illuminating all elements of the turn signal simultaneously, before sequentially turning them off. Turn signal colour has a US-spec red left rear turn signal and an international-spec amber right one. Until the early 1960s, most front turn signals worldwide emitted white light and most rear turn signals emitted red light. The American auto industry voluntarily adopted amber front turn signals for most vehicles beginning in the 1963 model year, though the advent of amber signals was accompanied by legal stumbles in some states and front turn signals were still legally permitted to emit white light until FMVSS 108 took effect for the 1968 model year, whereupon amber became the only permissible front turn-signal colour. Currently, most countries outside the United States and Canada require that all front, side and rear turn signals produce amber light. was built with amber rear turn signals from 2006 to 2008 and red ones from 2009 to 2014. In Belgium, Brazil, Canada, the GCC countries, Israel, Luxembourg, the Netherlands, Switzerland, and the US, the rear signals may be amber or red. Additionally, red turn signals can also be found in countries with trade agreements with the US such as Mexico and South Korea, and New Zealand. Proponents of red rear turn signals have claimed that they are less costly to manufacture, and automakers use the turn signal colour as a styling element to differentiate vehicles of different model years. It has been recognised since the 1960s that amber turn signals are more quickly spotted than red ones. A 2008 US study by the National Highway Traffic Safety Administration suggests vehicles with amber rear signals rather than red ones are up to 28% less likely to be involved in certain kinds of collisions, a followup 2009 NHTSA study determined there to be a significant overall safety benefit to amber rather than red rear turn signals, US studies in the early 1990s demonstrated improvements in the speed and accuracy of drivers' reactions to the stop lights of vehicles ahead when the turn signals were amber rather than red, and NHTSA determined in 2015 that amber rear turn signals can be provided at comparable cost to red ones. There is some evidence that turn signals with colourless clear lenses and amber bulbs may be less conspicuous in bright sunlight than those with amber lenses and colourless bulbs. Colour durability The amber bulbs commonly used in turn signals with colourless lenses are no longer made with cadmium glass, since various regulations worldwide, including the European RoHS directive, banned cadmium because of its toxicity. Amber glass made without cadmium is relatively costly, so With accumulated heat-cool cycles, though, some of these coatings may flake off the bulb glass, or the colour may fade. This causes the turn signal to emit white light rather than the required amber light. The international regulation on motor vehicle bulbs requires manufacturers to test bulbs for colour endurance. However, no test protocol or colour durability requirement is specified. Discussion is ongoing within the ''Groupe des Rapporteurs d'Éclairage'', the UNECE working group on vehicular lighting regulation, to develop and implement a colour durability standard. Rather than using an amber bulb, some signal lights contain an inner amber plastic enclosure between a colourless bulb and the colourless outer lens or by using integrated amber LEDs in a colourless enclosure which produces less heat. Rear Rear position lights (tail lights) Conspicuity for the rear of a vehicle is provided by rear position lights (also called tail lights). These are required to produce only red light and to be wired such that they are lit whenever the front position lights are lit, including when the headlights are on. Rear position lights may be combined with the vehicle's stop lights or be separate from them. In combined-function installations, the lights produce brighter red light as stop lights and dimmer red light as rear position lights. Regulations worldwide stipulate minimum intensity ratios between the bright (stop) and dim (position) modes, so that a vehicle displaying rear position lights will not be mistakenly interpreted as showing stop lights and vice versa. and in the Vienna Convention on Road Traffic, though they are often informally called brake lights. They are required to be fitted in multiples of two, symmetrically at the left and right edges of the rear of every vehicle. The CHMSL is generally required to illuminate steadily and not permitted to flash, though US regulators granted Mercedes-Benz a temporary 24-month exemption in January 2006 to the steady-light requirement to evaluate whether a flashing CHMSL provides an emergency stop signal that effectively reduces the likelihood of a crash. On passenger cars, the CHMSL may be placed above the back glass, affixed to the vehicle's interior just inside the back glass, or integrated into the vehicle's deck lid or into a spoiler. Other specialised fitments are sometimes seen; the Jeep Wrangler and Land Rover Freelander have the CHMSL on a stalk fixed to the spare wheel carrier. Trucks, vans, and commercial vehicles sometimes have the CHMSL mounted to the trailing edge of the vehicle's roof. The CHMSL is required by regulations worldwide to be centred laterally on the vehicle, though UN Regulation 48 permits lateral offset of up to 15 cm if the vehicle's lateral centre is not coincident with a fixed body panel, but instead separates movable components such as doors. Depending on the left and right lights' height, the lower edge of the CHMSL may be just above the left and right lights' upper edge. The 1952 Volkswagen Bus was equipped with only one stop light, mounted centrally and higher than the left and right rear lights, which did not produce a stop light function. The 1968–1971 Ford Thunderbird could be ordered with optional supplemental high-mounted stop and turn signal lights integrated into the left and right interior trim surrounding the rear glass. The Oldsmobile Toronado (from 1971 to 1978) and the Buick Riviera (from 1974 to 1976) had similar dual high-mounted supplemental stop/turn lights as standard equipment; these were located on the outside of the vehicle below the bottom of the rear glass. This type of configuration was not widely adopted at the time. Car and lighting manufacturers in Germany experimented with dual high-mount supplemental stop lights in the early 1980s, but this effort, too, failed to gain wide popular or regulatory support. Effective with the 1986 model year, the United States National Highway Traffic Safety Administration and Transport Canada mandated that all new passenger cars come equipped with a CHMSL. The requirement was extended to light trucks and vans for the 1994 model year. Early studies involving taxicabs and other fleet vehicles found that a third high-level stop light reduced rear-end collisions by about 50%. Once the novelty effect wore off as most vehicles on the road came to be equipped with a CHMSL, the crash-avoidance benefit declined. However, said benefit has not declined to zero, and a CHMSL has become so inexpensive to incorporate into a vehicle that it remains a cost-effective collision avoidance feature even at the long-term enduring crash-reduction benefit of 4.3%. A NHTSA report suggests that a vehicle equipped with a CHMSL has 23.7% less risk to be involved as a lead vehicle in a chain collision and 16.0% less risk to be involved as a middle vehicle in such a collision. Emergency stop signal (ESS) Emergency stop signalling is a lighting function wherein the vehicle's stop (brake) lights and/or hazard/turn indicators flash in phase at 3 to 5 Hz under heavy or urgent braking. The emergency stop signal is automatically activated if the vehicle speed is greater than and the emergency braking logic defined by regulation No. 13 (heavy vehicles), 13H (light vehicles), or 78 (motorcycles) is activated; the ESS may be displayed when a light vehicle's deceleration is greater than or a heavy vehicle's deceleration is greater than , and the ESS must be discontinued once the vehicle's deceleration drops below . Toyota, Mercedes-Benz, Volvo and BMW were among the earlier automakers to begin equipping vehicles with ESS. In 2013, Kia introduced the concept on some of their Australian-market models. Other methods of severe braking indication have also been implemented; some Volvo models make the stop lights brighter, and some BMWs have "Adaptive Brake Lights" that effectively increase the size of the stop lights under severe braking by illuminating them at brighter-than-normal intensity. As long as the brighter-than-normal stop lights are within the regulated maximum intensity for stop lights in general, this kind of implementation does not require specific regulatory approval, since the stop lights continue to operate in accord with general stop light regulations. The idea behind such emergency braking indicator systems is to catch following drivers' attention with increased urgency. However, there remains considerable debate over whether the system offers a measurable increase in safety. To date, studies of vehicles with ESS have not shown significant improvement. The systems used by BMW, Volvo, and Mercedes differ not only in operational mode (growing vs. intensifying vs. flashing, respectively), but also in such parameters as the deceleration threshold of activation. Data is being collected and analyzed in an effort to determine how such a system might be implemented to maximize a safety benefit, if such a benefit can be realized with visual emergency braking displays. An experimental study at the University of Toronto has tested stop lights which gradually and continuously grow in illuminated area with increasing braking. The ESS is not expensive because it reuses existing warning and stop signals. One potential problem with flashing stop lights in the United States and Canada is regulations that permit flashing stop lights to be used as rear turn signal and hazard lights, in lieu of separate dedicated lights. Rear fog lights is illuminated either by a single or a pair of yellow or white light(s), affixed within the indentation of the trunk or bumper. It is designed to light the surface of the plate without creating light directly visible to the rear of the vehicle, and must be illuminated whenever the position lights are lit. On large vehicles Large vehicles such as trucks and buses are in many cases required to carry additional lighting devices beyond those required on passenger vehicles. The specific requirements vary according to the regulations in force where the vehicle is registered. Identification lights In the US and Canada, vehicles over wide must be equipped with three amber front and three red rear identification lights spaced apart at the centre of the front and rear of the vehicle, as high as practicable. End-outline marker lights UN Regulation 48 requires vehicles exceeding in width to be equipped with white front and red rear end-outline marker lights on both the left and right, by the late 1960s, regulations around the world came to require all new vehicles to be so equipped. Operation of the warning signals must be from a control independent of the turn signal control, and an audiovisual tell-tale must be provided to the driver. In most vehicles, the hazard warning signals can be switched on and off with a physical push-button, which is typically marked with a triangular symbol, symbolizing a warning triangle. This function is meant to indicate a hazard such as a vehicle stopped in or near moving traffic, a disabled vehicle, a vehicle moving substantially slower than the flow of traffic such as a truck climbing a steep grade, the presence of stopped or slow traffic ahead on a high-speed road and/or the presence of stopped or slow traffic ahead on unpredictable natural disasters like earthquakes, floods, landslides. In vehicles with separate left and right green turn signal tell-tale on the dashboard, both left and right indicators may flash to provide a visual indication of the hazard flashers' operation. In vehicles with a single green turn signal tell-tale on the dashboard, a separate red tell-tale must be provided for hazard flasher indication. Because the hazard flasher function operates the vehicle's left and right turn signals, a left or a right turn signal function may not be provided while the hazard flashers are operating. Apart from its use as emergency lighting, a single flash of the hazard lights is used to show gratitude to yielding drivers in several countries. However, in the United Kingdom, they must not be used except to warn others of either a temporary obstruction when the vehicle is stationary or a hazard ahead on a dual carriageway with a speed limit of at least 50 mph. Retroreflectors "Retroreflectors" (also called "reflex reflectors") produce no light of their own, but rather reflect incident light towards its source, such as another driver's headlights. They are regulated as automotive lighting devices, and specified to account for the separation between a vehicle's headlights and its driver's eyes. Thus, vehicles can remain conspicuous even with their lights off. Regulations worldwide require all vehicles and trailers to be equipped with rear-facing red retroreflectors; in countries where UN Regulation No. 48 is applied, these must be triangular on trailers and non-triangular on vehicles other than trailers. Such systems have in the past been sold as aftermarket accessories, but are today seldom seen in traffic. Front brake lights Since the late 1960s, there have been proposals to introduce a front-mounted brake light, where green or blue lights would indicate to pedestrians at crossings that an approaching vehicle is slowing down. Front brake lights were demonstrated in concept cars including the 1967 Explorer IV and the ==Interior and convenience lights==

Most cars have at least one "dome light" (or "courtesy light") located in or near the ceiling of the passenger compartment, to provide illumination by which to fasten seatbelts and enter or exit the car. These often have an option to automatically switch on when the front (or any) passenger doors are opened. Many vehicles have expanded this feature, causing the overhead interior light to remain on after all doors are closed, allowing passengers to fasten seat belts with added illumination. The extended lighting cycle usually ends when the vehicle's ignition has begun, or a gradual reduction in light emitted after a couple of minutes if the car is not started, called "theater" lighting. Interior lighting has been added on some vehicles at the bottom edge of the dashboard, illuminating the floor for front passengers, or underneath the front seats at the rear, illuminating the floor for rear passengers. This type of convenience lighting approach is also sometimes used to illuminate interior or exterior door handles, exterior step running boards, or electric window switches. LED light sources appear increasingly as interior convenience lights in various locations, especially with finely focused lighting on console control surfaces and in cabin storage areas. Map lights are aimed at specific passenger positions and allow for reading without glare distraction to the driver. Some vehicles have "approach lighting" or "puddle lights" (lights that illuminate the ground outside the doors) in the exterior mirrors or lower edges of the doors, as well as interior lighting activated via key fob. Many cars have lights in the trunk, the engine compartment, the glove box, and other storage compartments. Modern pickup trucks usually have one or more white cargo lights that illuminate the bed of the truck, often controlled in conjunction with the interior dome lighting. Most gauges and controls on a dashboard in modern vehicles are illuminated when the headlights are turned on, and the intensity of light can be adjusted by the driver for comfort. Saab automobiles, for example, have an aircraft-style "night panel" function that shuts off all interior illumination save for the speedometer (unless attention is called to a critical situation on another gauge) to improve the driver's night vision. ==On service vehicles==

Emergency vehicle lights Emergency vehicles such as fire engines, ambulances, police cars, snow-removal vehicles and tow trucks are usually equipped with intense warning lights of particular colours. These may be motorised rotating beacons, xenon strobes, or arrays of LEDs. The prescribed colours differ by jurisdiction; in most countries, blue and red special warning lights are used on police, fire, and medical-emergency vehicles. In the United States and some other jurisdictions, amber lights are for tow trucks, private security personnel, construction vehicles, and other nonofficial special-service vehicles, while volunteer firefighters use red, blue, or green, depending on jurisdiction. In the US it is a violation of the DOT (Department of Transportation) Uniform Vehicle Code for any non-emergency vehicle (Police/Fire/Ambulance) to operate forward-facing red lights of any kind. Cars in the US only have red tail lights, and no blue lights; a vehicle displaying a red (forward-facing) light (flashing or not) coming towards a driver, or from behind the driver (in rearview mirror) indicates that an official emergency vehicle is coming, requiring the driver to yield, pull off to the side of the road, or otherwise get out of its way. Some US states allow emergency vehicles to have blue lights that can be turned on to warn drivers of an emergency vehicle in action; blue and red lights can be combined, forward- and/or rear-facing. In the UK, doctors may use green warning lights; although these do not allow the user to claim any exemption from road traffic regulations (compared to the blue lights used by statutory emergency services when responding to calls). Special warning lights, usually amber, are also sometimes mounted on slow or wide vehicles such as mobile cranes, excavators, tractors, and even mobility scooters in certain conditions. Taxi displays Standard taxicabs for street hire are distinguished by special lights affixed to the vehicle's roof in accordance with local regulations. They may have an illuminated "Taxi" sign, a light to signal that they are ready to take passengers, or off duty, or an emergency panic light the driver can activate in the event of a robbery to alert passersby to call the police. Depending on local regulations, the "Taxi" sign may also be required to display a number identifying the vehicle. ==Light sources==

reflector to achieve a directed beam Incandescent lights The incandescent light bulb was for a long time the only light source used in automotive lighting. Incandescent bulbs are still commonly used in turn signals to stop hyper-flashing of the turn signal flashers. Many types of bulbs have been used. Standardized type numbers are used by manufacturers to identify bulbs with the same specifications. Bases may be bayonet-type with one or two contacts, plastic or glass wedges, or dual wire loops or ferrules used on tubular "festoon" lights. Screw-base lights are never used in automobile applications due to their loosening under vibration. Signal lights with internal or external coloured lenses use colourless bulbs; conversely, lights with colourless lenses may use red or amber bulbs to provide light of the required colours for the various functions. Typically, bulbs of 21 to 27 watts producing 280 to 570 lumens (22 to 45 mean spherical candlepower) are used for stop, turn, reversing and rear fog lights, while bulbs of 4 to 10 W, producing 40 to 130 lm (3 to 10 mscp) are used for tail lights, parking lights, side marker lights and side turn signal repeaters. Tungsten-halogen lights are a very common light source for headlights and other forward illumination functions. Some recent vehicles use small halogen bulbs for exterior signalling and marking functions, as well. The first halogen light approved for automotive use was the H1, which used 55 watts producing 1500 lumens and was introduced in Europe in 1962. Light-emitting diodes (LED) Since 1993, light-emitting diodes (LEDs) have increasingly been used in automotive lighting. They offer a very long service life, extreme vibration resistance, high colour durability, high efficiency (lumen/Watt) and can benefit from considerably more compact packaging compared to most bulb-type assemblies. LEDs also offer a potential safety benefit when employed in stop lights; when power is applied, they rise to full intensity approximately 250 milliseconds (¼ second) faster than incandescent bulbs. This effectively instant rise time theoretically provides following drivers more time to react to the stop light signal, but has not been shown to make cars with LED stop lights less likely to be struck from behind. LEDs were first applied to automotive lighting in centre high-mount stop lamps (CHMSLs), beginning with the 1986 Chevrolet Corvette (C4). Adoption of LEDs for other signal functions on passenger cars is gradually increasing with demand for the technology and related styling updates. The first car registered to drive on the road with full LED rear lights was Land Rover's LCV 2/3 concept car in the 1990s. At the time, the only light function that was difficult to reproduce was the reverse light, as white LEDs did not yet exist. The reverse function was only achievable with the introduction of blue LEDs; by mixing red, green and blue LEDs in a defined distributed pattern behind a lens, white light was produced that conformed to the legal requirements of a reverse light. The Maserati 3200GT, introduced in 1999, was the first production car to use full LED taillights. In North America, the 2000 Cadillac Deville was the first passenger car with LED taillights. The 2002 Kia Opirus was an early adopter of LED front turn signals. The 2007 Audi R8 used two strips of optically focused high-intensity LEDs for its daytime running lights. Optional on the R8 outside North America were the world's first LED headlights, made by AL-Automotive Lighting. The low and high beams, along with the position (parking) light and front turn signal, all use LEDs. The Lexus LS 600h (XF40) features LED low beam, position and side marker lights in North America, and the 2009 Cadillac Escalade Platinum used LEDs for the low and high beams, as well as for the position and side marker lights. The Mercedes-Benz S-Class (W222) used entirely LED lights, even in the most basic trim level. LED lights are used for flashing beacon lights on vehicles such as maintenance trucks. In addition, UN Regulation 112 contains a set of tests for LED modules, including colour rendering, UV radiation, and temperature stability tests. According to UN Regulations 112 and 123, mechanical, electromechanical or other devices for headlights must withstand endurance tests and function failure tests. High intensity discharge (HID) High-intensity discharge, or HID lights, sometimes referred to as "xenon lights", are modified metal halide lights employing xenon fill gas. Traditional HID lights, such as those used for general lighting, have a long warm-up time. Headlights must provide light very shortly after they are turned on, and the xenon gas serves to reduce warm-up time. Neon tubes Neon light tubes were introduced into series production for the centre high-mount stop light on the 1995 Ford Explorer. Notable later uses included the 1998 Lincoln Mark VIII with a neon tube spanning the width of the trunk decklid, and the BMW Z8, which made extensive use of neon. Neon lights offer the same nearly instant rise time as LEDs, but require a high-voltage ballast. == Self driving ==

In December 2023, Mercedes-Benz received approval in California and Nevada, the only states where it is legal to operate their self-driving vehicles, for turquoise lights in accordance with SAE standard J3134, to indicate to outside observers that the car's self-driving system is engaged. Mercedes is the first car manufacturer to equip their self-driving vehicles with such lights. ==Distributive lighting==

In distributive light systems, the light from a single source is sent via optical fibres or light guides to wherever it is needed in the automobile. Light guides are commonly used to distributively light dashboard displays, and premium vehicles are beginning to use distributive systems for lighting such items as door locks, window controls, and cup holders. Distributive exterior lighting has also been explored, with high-intensity central light sources. ==See also==