Carguy at 18:59, 28 June 2006

2006-06-28T18:59:27Z

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'''Daytime Running Lamps''' ("'''[[Daytime Running Lights|DRL]]'''", also "Daylight Running Lamps", "Daytime Running Lights") are [[automotive lighting|lighting devices]] on the front of roadgoing [[motor vehicle]]s, automatically switched on when the vehicle is moving forward, and intended to increase the conspicuity of the vehicle during daylight conditions.

==Scientific study==
Scientific study of the value of DRLs has yielded widely divergent results. It is problematic and difficult to apply the successful results obtained in Scandinavian countries to jurisdictions like the U.S., Canada and Australia, for the ambient light conditions and vehicles in use are extremely different. Studies conducted in North America have thus far not shown a conclusive safety benefit to [[Daytime Running Lights|DRL]], and have raised questions about possible safety disbenefits, e.g. turn signal masking, motorcycle safety reduction and/or glare, from certain [[Daytime Running Lights|DRL]] implementations. Nevertheless, a safety improvement is at least suggested by many studies.

==Regulations Worldwide==
===Scandinavia===
[[Daytime Running Lights|DRL]] were first mandated in Scandinavian countries, where ambient light levels are generally low even during the day. Finland was the first country to require [[Daytime Running Lights|DRL]] in 1972. Sweden adopted the same requirement in 1977, Norway in 1986, Iceland in 1988, and Denmark in 1990. The [[Daytime Running Lights|DRL]] regulations in these countries initially favored the use of 21-watt signal bulbs identical to those used in brake lamps and turn signals, mounted at the extreme outer left and right edges of the front of the vehicle, and producing approximately 400 to 600 candela on axis. To increase manufacturer flexibility in complying with the requirement for [[Daytime Running Lights|DRL]], the daytime illumination of low-beam [[headlight]]s was added as an optional implementation. Given the [[UNECE]] headlight specifications in use in those countries, such an implementation would produce approximately 400 cd axially. Headlamp-based [[Daytime Running Lights|DRL]] were required in Hungary starting in 1989. In all cases, DRLs were required to produce white light.

===Canada===
Canada Motor Vehicle Safety Standard 108 required [[Daytime Running Lights|DRL]] on all new cars made after January 1 1990. Canada's proposed [[Daytime Running Lights|DRL]] regulation initially was extremely similar to regulations in place in Scandinavia, with an axial luminous intensity limit of 1,500 candela, but automakers objected, claiming it was too expensive to add a new front lighting device, and would increase warranty costs (by dint of increased bulb replacements) to run the low beams. After a pitched 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. These changes to the regulation permitted automakers to implement less-costly [[Daytime Running Lights|DRL]], such as by connecting the high beam filaments in series to supply each filament with half its rated voltage, or by burning the front [[turn signals]] full time (except when actually flashing as turn indicators).

===United States===
[[GMC|General Motors]], interested in reducing the build variations of cars for the North American market, began lobbying the DOT (United States Department of Transportation) to permit [[Daytime Running Lights|DRL]] in the United States shortly after Canada required them. A prolonged regulatory battle was fought, with the DOT objecting on grounds of potential safety drawbacks and glare issues. Eventually, however, these objections were set aside and [[Daytime Running Lights|DRL]] were legalized (but not mandated) effective with the 1995 model year. General Motors immediately equipped most (and, in following years, all) of its vehicles with [[Daytime Running Lights|DRL]]. Saab, Volkswagen and Subaru gradually introduced [[Daytime Running Lights|DRL]] in the U.S. market beginning in 1995.

Public reaction to [[Daytime Running Lights|DRL]], mostly positive in Canada, was decidedly mixed in the U.S. (where [[motorcycles]] have been required since 1976 to be wired so as to burn the low beam headlamp whenever the engine is running). Thousands of complaints regarding glare from [[Daytime Running Lights|DRL]] were lodged with the DOT shortly after the lights were allowed, and there was also some concern that [[Daytime Running Lights|DRL]] based on front turn signals introduce ambiguity into the turn signal system. In 1997, in response to these complaints and after measuring actual [[Daytime Running Lights|DRL]] intensity well above the 7,000 cd limit on vehicles in use, DOT proposed changes to the [[Daytime Running Lights|DRL]] specification that would have capped axial intensity at 1,500 candela, a level nearly identical to the European 1,200 cd and identical to the initially-proposed Canadian limit. During the open comment period, thousands of public comments were received by DOT in support of lowering the intensity (or advocating the complete elimination of [[Daytime Running Lights|DRL]] from U.S. roads). Automaker sentiment generally ran along predictable lines, with European automakers experienced at complying with European [[Daytime Running Lights|DRL]] requirements voicing no objection to the proposal, and North American automakers vociferously repeating the same objections they raised in response to Canada's initial proposal. The DOT proposal for [[Daytime Running Lights|DRL]] intensity reduction was rescinded in 2004.

===Great Britain===
UK regulations briefly required vehicles first used on or after 1 April 1987 to be equipped with a '''dim-dip''' device or daytime running lamps, except such vehicles as comply fully with [[World Forum for Harmonization of Vehicle Regulations|ECE Regulation 48]] regarding installation of lighting equipment. A dim-dip device operates the low beam headlamps (called "dipped beam" in the UK) at between 10 percent and 20 percent of normal low-beam intensity. UK DRLs must emit at least 200 candela straight ahead, and no more than 800 candela in any direction. These regulatory provisions were based on [http://dastern.torque.net/techdocs/DimDip2.html ILPE research and recommendations]. In practise, most vehicles were equipped with the dim-dip option, rather than DRLs, and the Dim-Dip requirement was quashed by the European Commission. See [[Automotive lighting]] for more information.

==See also==
*[[Automotive Lighting]]
*[[Headlamp]]
*[[Federal Motor Vehicle Safety Standard 108]]

==External links==
*[http://dms.dot.gov/search/searchFormSimple.cfm U.S. DOT Docket Viewer] (Enter docket # 4124 to view U.S. DOT [[Daytime Running Lights|DRL]] regulation proposal and comments thereto)
*[http://www.lightsout.org/ Association of Drivers Against Daytime Running Lights]
*[http://headlightson247.com/ Let's TURN 'EM ON - Headlights On 24/7] (Austrailian [[Daytime Running Lights|DRL]] activist website)
*[http://http://dastern.torque.net/techdocs/dimdip.html UK Dim-Dip Regulatory History]
*[http://www.unece.org/trans/main/wp29/wp29regs/87rv1am1e.pdf ECE Regulation 87 concerning Daytime Running Lamps]

[[Category:Automotive technologies]]

Daytime Running Lights - Revision history

Carguy at 18:59, 28 June 2006