Automotive Lighting: http://en.wikipedia.org/wiki/Automotive_lighting#Daytime_running_lampsWikipedia entry on "Automotive Lighting" said:Nighttime standing-vehicle conspicuity to the front is provided by "front position lamps", known as "parking lamps" or "parking lights" in North America, and "front sidelights" in British English. Despite the UK term, these are not the same as the side marker lights described below. The front position lamps may emit white or amber light in North America; elsewhere in the world they must emit only white light. Colloquial city light terminology for front position lamps derives from the practice, formerly adhered to in cities like Moscow, London and Paris, of driving at night in built-up areas using these low-intensity lights rather than headlamps. It is now illegal in many countries to drive a vehicle with parking lamps illuminated, unless the headlamps are also illuminated.
Some countries permit or require vehicles to be equipped with daytime running lamps (DRL). These may be functionally-dedicated lamps, or the function may be provided by, e.g., the low beam or high beam headlamps, the front turn signals, or the front fog lamps, depending on local regulations. In ECE Regulations, a functionally-dedicated DRL must emit white light with an intensity of at least 400 candela on axis and no more than 1200 candela in any direction. Most countries applying ECE Regulations permit low beam headlamps to be used as daytime running lamps. Canada, Sweden, Norway, Slovenia, Finland, Iceland, and Denmark require hardwired automatic DRL systems of varying specification depending on the specific country. DRLs are permitted in many countries where they are not required, but prohibited in other countries not requiring them.
In North America, daytime running lamps may produce up to 7,000 candela, and can be implemented as high-beam headlamps running at less-than-rated voltage. This has provoked a large number of complaints about glare.