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A daytime running lamp (DRL, also daytime running light) is an
automotive lighting
The lighting system of a motor vehicle consists of lighting and signalling devices mounted to or integrated into the front, rear, sides, and in some cases the top of a motor vehicle. They illuminate the road ahead for the driver and increase t ...
and
bicycle lighting
Bicycle lighting is illumination attached to bicycles whose purpose above all is, along with reflectors, to improve the visibility of the bicycle and its rider to other road users under circumstances of poor ambient illumination. A secondary p ...
device on the front of a roadgoing
motor vehicle
A motor vehicle, also known as motorized vehicle or automotive vehicle, is a self-propelled land vehicle, commonly wheeled, that does not operate on Track (rail transport), rails (such as trains or trams) and is used for the transportation of pe ...
or bicycle, automatically switched on when the vehicle's
handbrake has been pulled down, when the vehicle is in gear, or when the engine is started, emitting white,
yellow
Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the R ...
, or amber light. Their intended use is not to help the driver see the road or their surroundings, but to help other road users identify an active vehicle.
Implementations
![Lowbeam DRL](https://upload.wikimedia.org/wikipedia/commons/5/52/Lowbeam_DRL.jpg)
Depending on prevailing regulations and equipment, vehicles may implement the daytime-running light function by functionally turning on specific lamps, by operating low-beam headlamps or fog lamps at full or reduced intensity, by operating high-beam headlamps at reduced intensity, or by steady-burning operation of the front turn signals. Compared to any mode of headlamp operation to produce the daytime running light, functionally dedicated DRLs maximize the potential benefits in safety performance, glare, motorcycle masking, and other potential drawbacks.
[ ]
Usage
A daytime running lamp is usually automatically switched on once the ignition is on; other vehicles may switch the daytime running lamps on when the parking brake is released or when the vehicle is shifted into gear. A daytime running lamp emits a brighter light when the headlamps are not turned on and its brightness will be dimmed slightly in conjunction with the headlamps being turned on.
Safety performance
A 2008 study by the U.S.
National Highway Traffic Safety Administration
The National Highway Traffic Safety Administration (NHTSA ) is an agency of the U.S. federal government, part of the Department of Transportation. It describes its mission as "Save lives, prevent injuries, reduce vehicle-related crashes" rela ...
analysed the effect of DRLs on frontal and side-on crashes between two vehicles and on vehicle collisions with pedestrians, cyclists, and motorcyclists. The analysis determined that DRLs offer no statistically significant reduction in the frequency or severity of the collisions studied, except for a reduction in light trucks' and vans' involvement in two-vehicle crashes by a statistically significant 5.7%.
Effect of ambient light
The daytime running light was first mandated, and safety benefits first perceived, in Scandinavian countries where it is persistently dark during the winter season. As ambient light levels increase, the potential safety benefit decreases while the DRL intensity required for a safety improvement increases. The safety benefit produced by DRLs in relatively dark Nordic countries is roughly triple the benefit observed in the relatively bright United States.
[
]
Effect on motorcycle safety
A number of motorcycling advocacy Motorcycling advocacy is activism for motorcyclists seeking to establish and protect their rights, and to influence issues of interest to the motorcycling community. This includes lobbying organizations that work to influence laws, and groups or ind ...
groups are concerned over reduced motorcycle conspicuity and increased vulnerability with the introduction of headlamp-based DRLs on cars and other dual-track vehicles, since it means motorcycles are no longer the only vehicles displaying headlamp
A headlamp is a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage, ''headlamp'' is the term for the device itself and ''headlight'' is the term for ...
s during the day. Some researchers have suggested that amber
Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In Ma ...
DRLs be reserved for use exclusively on motorcycles, in countries where amber is not presently a permissible color for DRLs on any vehicles, while other research has concluded there is a safety disbenefit to two 90 mm x 520 candela
The candela ( or ; symbol: cd) is the unit of luminous intensity in the International System of Units (SI). It measures luminous power per unit solid angle emitted by a light source in a particular direction. Luminous intensity is analogous to ...
(cd) DRLs on motorcycles in comparison to one 190 mm x 270 cd dipped (low) beam headlight. The latter result suggests that a daytime running lamp's luminous area may have an important influence on its effectiveness.
Environmental impact
DRL power consumption varies widely depending on the implementation. Current production DRL systems consume from 5 watts (dedicated LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
system) to over 200 W (headlamps and all parking, tail, and marker lights on). International regulators, primarily in Europe, are working to balance the potential safety benefit offered by DRL with the increased fuel consumption due to their use. Because the power to run the DRLs must be produced by the engine, which in turn requires burning additional fuel, high-power DRL systems increase CO2 emissions sufficiently to affect a country's compliance with the Kyoto protocol
The Kyoto Protocol was an international treaty which extended the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions, based on the scientific consensus that (part ...
on greenhouse gas emissions
Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and lar ...
. For that reason, low-power solutions are being encouraged and headlamp-based systems are not allowed after DRLs became mandatory in Europe at the beginning of 2011. LEDs and low-power, high-efficacy, long-life light bulbs produce appropriate amounts of light for an effective DRL without significantly increasing fuel consumption or emissions. Fuel consumption reductions of up to 0.5 mpg may be found when comparing a 55 W DRL system to a 200 W DRL system. In 2006, the UK's Department of Transport also found significant reductions in emissions and fuel consumption when comparing a 42 W DRL system to a 160 W full headlight DRL systems. DRL fuel consumption can be reduced to insignificant levels by the use of 8 to 20 W DRL systems based on LEDs or high-efficacy filament bulbs.
Worldwide
European Union
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
Directive 2008/89/EC required all passenger cars and small delivery vans first type approved on or after 7 February 2011 in the EU to come equipped with daytime running lights. European Union Directive 2008/89/EC ended validity on 31 October 2014, implicitly repealed by the replacement Regulation (EC) No 661/2009. The mandate was extended to trucks and buses in August 2012. Functional piggybacking, such as operating the headlamps or front turn signals or fog lamps as DRLs, is not permitted; the EU Directive requires functionally specific daytime running lamps compliant with ECE Regulation 87 and mounted to the vehicle in accordance with ECE Regulation 48. DRLs compliant with R87 emit white light on an axis of between 400 and 1,200 candela with an apparent surface of 25 cm2 to 200 cm2 with an additional requirement of between 1 and 1,200 candela in a defined field.
In the past, Germany, Spain, France and other European countries have encouraged or required daytime use of low beam headlamps on certain roads at certain times of year; Ireland encourages the use of low beam headlights during the winter, Italy, Hungary and Romania require daytime running lamps outside populated areas, and Bulgaria, Czech Republic, Estonia, Kosovo, Latvia, Lithuania, North Macedonia, Montenegro, Poland, Serbia, Slovakia and Slovenia require the use of full or reduced voltage low beam headlights at all times. Whether this requirement is met by the DRLs required on new cars since February 2011 is a matter of individual countries' laws.
Nordic countries
DRLs were first mandated in the Nordic countries
The Nordic countries (also known as the Nordics or ''Norden''; literal translation, lit. 'the North') are a geographical and cultural region in Northern Europe and the Atlantic Ocean, North Atlantic. It includes the sovereign states of Denmar ...
, where ambient light levels in the winter are generally low even during the day. Sweden was the first country to require widespread DRLs in 1977. At the time, the function was known as ''varselljus'' ("perception light" or "notice light"). The initial regulations in these countries favored devices incorporating 21 W signal bulbs identical to those used in brake lamps and turn signals, producing yellow
Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the R ...
or white light of approximately 400 to 600 cd on a axis
An axis (plural ''axes'') is an imaginary line around which an object rotates or is symmetrical. Axis may also refer to:
Mathematics
* Axis of rotation: see rotation around a fixed axis
*Axis (mathematics), a designator for a Cartesian-coordinate ...
, mounted at the outer left and right edges of the front of the vehicle. Finland adopted a daytime-light requirement in 1972 on rural roads in wintertime, and in 1982 on rural roads in summertime and 1997 on all roads all year long; Norway in 1985, Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
in 1988, and Denmark
)
, song = ( en, "King Christian stood by the lofty mast")
, song_type = National and royal anthem
, image_map = EU-Denmark.svg
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Danish Realm, Kingdom of Denmark
...
in 1990. To increase manufacturer flexibility in complying with the requirement for DRLs, the daytime illumination of low beam headlight
A headlamp is a lamp (electrical component), lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage (language), usage, ''headlamp'' is the term for the ...
s was added as an optional implementation. Given the headlamp specifications in use in those countries, such an implementation would produce approximately 450 cd axially.
United Kingdom
UK regulations briefly required vehicles first used on or after 1 April 1987 to be equipped with a ''dim-dip'' device
or functionally dedicated daytime running lamps, except those vehicles type-approved to ECE Regulation 48 regarding installation of lighting equipment—this exception was made because ECE R48 did not require dim-dip or daytime running lights, and while countries signatory to the ECE Regulations are permitted to maintain their own national regulations as an option to the ECE regulations, they are not permitted to bar vehicles approved under the ECE regulations. The dim-dip system operated the low beam headlamps (called "dipped beam" in the UK) at between 10% and 20% of normal low beam intensity. The running lamps permitted as an alternative to dim-dip were required to emit at least 200 cd straight ahead, and no more than 800 cd in any direction. In practice, most vehicles were equipped with the dim-dip option rather than the running lamps.[
The dim-dip lights were not intended for use as daytime running lights. Rather, they operated when the engine was running and the driver switched on the front position (parking) lamps. Dim-dip was intended to provide a nighttime "town beam" with intensity between that of the parking lamps commonly used at the time by British drivers in city traffic after dark, and low beam headlamps; the former were considered insufficiently intense to provide improved conspicuity in conditions requiring it, while the latter were considered too glaring for safe use in built-up areas. The UK was the only country to require such dim-dip systems, though vehicles so equipped were sold in other ]Commonwealth
A commonwealth is a traditional English term for a political community founded for the common good. Historically, it has been synonymous with "republic". The noun "commonwealth", meaning "public welfare, general good or advantage", dates from the ...
countries with left-hand traffic
Left-hand traffic (LHT) and right-hand traffic (RHT) are the practices, in bidirectional traffic, of keeping to the left side or to the right side of the road, respectively. They are fundamental to traffic flow, and are sometimes referred to ...
.
In 1988, the European Commission
The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...
successfully prosecuted the UK government in the European Court of Justice
The European Court of Justice (ECJ, french: Cour de Justice européenne), formally just the Court of Justice, is the supreme court of the European Union in matters of European Union law. As a part of the Court of Justice of the European Un ...
, 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.[ Nevertheless, dim-dip systems remain permitted, and while such systems are not presently as common as they once were, dim-dip functionality was fitted on many new cars (such as the ]Volkswagen Polo
The Volkswagen Polo is a supermini car (B-segment) produced by the German car manufacturer Volkswagen since 1975. It is sold in Europe and other markets worldwide in hatchback, saloon, and estate variants throughout its production run.
History
...
) well into the 1990s.
Canada
Canada Motor Vehicle Safety Standard 108 requires DRLs on all new vehicles made or imported after January 1, 1990. Canada's proposed DRL regulation was essentially similar to regulations in place in Scandinavia, with an axial luminous intensity
In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. ...
limit of 1,500 cd, but automakers claimed it was too expensive to add a new front lighting device, and would increase warranty costs (due to increased bulb replacements) to run the low beams. After a regulatory battle, the standard was rewritten to permit the use of reduced-voltage high beam headlamps producing up to 7,000 axial candela, as well as permitting any light color from white to amber or selective yellow
Selective yellow is a colour for automotive lamps, particularly headlamps and other road-illumination lamps such as fog lamps. Under ECE regulations, headlamps were formerly permitted to be either white or selective yellow—in France, selectiv ...
. These changes to the regulation permitted automakers to implement a less costly DRL, such as by connecting the high beam filaments in series
Series may refer to:
People with the name
* Caroline Series (born 1951), English mathematician, daughter of George Series
* George Series (1920–1995), English physicist
Arts, entertainment, and media
Music
* Series, the ordered sets used in ...
to supply each filament with half its rated voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...
, or by burning the front turn signals
The lighting system of a motor vehicle consists of lighting and signalling devices mounted to or integrated into the front, rear, sides, and in some cases the top of a motor vehicle. They illuminate the road ahead for the driver and increase th ...
full-time except when they are actually flashing as turn indicators.
United States
Shortly after Canada mandated DRLs, General Motors
The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
, interested in reducing the build variations of cars for the North American market, petitioned the U.S. National Highway Traffic Safety Administration
The National Highway Traffic Safety Administration (NHTSA ) is an agency of the U.S. federal government, part of the Department of Transportation. It describes its mission as "Save lives, prevent injuries, reduce vehicle-related crashes" rela ...
in 1990 to permit (but not require) US vehicles to be equipped with DRLs like those in Canada.[Federal Register 98-20918 NPRM: Federal Motor Vehicle Safety Standards Lamps, Reflective Devices, and Associated Equipment]
/ref> NHTSA objected on grounds of the potential for high-intensity DRLs to cause problems, such as glare and turn signal masking, and issued a proposed rule in 1991 that specified a maximum intensity of 2,600 cd.[ Industry and safety watchdogs reacted to the proposed rule,][ and eventually the glare objections were set aside and most of the same types of DRLs allowed in Canada were permitted but not required effective with the 1995 model year.][ General Motors immediately equipped most (and, in following years, all) of its vehicles with DRLs beginning with the ]Chevrolet Corsica
The Chevrolet Corsica (named after Corsica, France) is a front-wheel drive compact car that was produced by Chevrolet from 1987 until 1996. The Corsica was built upon the L-body platform. It shared the L-body with the 2-door Beretta, and the reb ...
. Saab
Saab or SAAB may refer to:
Brands and enterprises
* Saab Group, a Swedish aerospace and defence company, formerly known as SAAB, and later as Saab AB
** Datasaab, a former computer company, started as spin off from Saab AB
* Saab Automobile, a fo ...
, Volkswagen
Volkswagen (),English: , . abbreviated as VW (), is a German Automotive industry, motor vehicle manufacturer headquartered in Wolfsburg, Lower Saxony, Germany. Founded in 1937 by the German Labour Front under the Nazi Party and revived into a ...
, Volvo
The Volvo Group ( sv, Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distributio ...
, Suzuki
is a Japan, Japanese multinational corporation headquartered in Minami-ku, Hamamatsu, Japan. Suzuki manufactures automobiles, motorcycles, All-terrain vehicle, all-terrain vehicles (ATVs), outboard motor, outboard marine engines, wheelchairs ...
and Subaru
( or ; ) is the automaker, automobile manufacturing division of Japanese transportation conglomerate (company), conglomerate Subaru Corporation (formerly known as Fuji Heavy Industries), the Automotive industry#By manufacturer, twenty-first ...
gradually introduced DRLs in the U.S. market beginning in 1995. In recent years, Lexus
is the luxury vehicle division of the Japanese automaker Toyota. The Lexus brand is marketed in more than 90 countries and territories worldwide and is Japan's largest-selling make of premium cars. It has ranked among the 10 largest Japanese ...
has installed high-beam or turn signal based DRLs on US models. Some Toyota
is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
models come with DRLs as standard or optional equipment, and with a driver-controllable on and off switch. Starting in the 2006 model year, Honda
is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan.
Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
began equipping their U.S. models with DRLs, mostly by reduced-intensity operation of the high beam headlamps.
Public reaction to DRLs, generally neutral to positive in Canada, is decidedly mixed in the U.S. Thousands of complaints regarding glare from DRLs were lodged with the DOT shortly after DRLs were permitted on cars, and there was also concern that headlamp-based DRLs reduce the conspicuity of motorcycles, and that DRLs based on front turn signals introduce ambiguity into the turn signal system.[ In 1997, in response to these complaints and after measuring actual DRL intensity well above the 7,000 cd limit on vehicles in use, DOT proposed changes to the DRL specification that would have capped axial intensity at 1,500 cd, a level equivalent to the European 1,200 cd and identical to the initially proposed Canadian limit.][ During the open comment period, a volume of public comments were received by NHTSA in support of lowering the intensity or advocating the complete elimination of DRLs from U.S. roads. Automaker sentiment generally ran along consistent lines, with European automakers experienced at complying with European DRL requirements voicing no objection to the proposal, and North American automakers repeating the same objections they raised in response to Canada's initial 1,500-cd proposal.][docket for DRL glare complaints]
/ref> The NHTSA proposal for DRL intensity reduction was rescinded in 2004, pending agency review and decision on a petition filed in 2001 by General Motors, seeking to have NHTSA mandate DRLs on all U.S. vehicles.[Federal Register E9-15314: Denial of GM Petition to Mandate DRLs]
/ref> The GM petition was denied by the NHTSA in 2009, on grounds of severe methodological and analytical flaws in the studies and data provided by GM as evidence for a safety benefit to DRLs.[ In denying the petition, the NHTSA said:
Several states on the Eastern seaboard, the Southeast, Gulf Coast and California have laws that require headlights to be switched on when windshield wipers are in use. DRLs are not considered headlights in most vehicle codes and so DRLs may not meet the letter of these laws in use.
]
Australia
DRLs are permitted but not required in Australia, though the Australian College of Road Safety, an Australian automotive safety group, advocates making DRLs mandatory rather than optional.
See also
* Automobile safety
Automotive safety is the study and practice of design, construction, equipment and regulation to minimize the occurrence and consequences of traffic collisions involving motor vehicles. Road traffic safety more broadly includes roadway design.
...
* Bicycle safety
Bicycle safety is the use of road traffic safety practices to reduce risk associated with cycling. Risk can be defined as the number of incidents occurring for a given amount of cycling. Some of this subject matter is hotly debated: for example ...
References
External links
Headlights overview
Insurance Institute for Highway Safety (IIHS)
{{DEFAULTSORT:Daytime Running Lamp
Automotive lamps
Vehicle safety technologies