Audi has been at the forefront of using DRL light signatures as a design feature

Audi has been at the forefront of using DRL 'light signatures' as a design feature

Automotive lighting continues to see rapid product development underpinned by advanced technologies and the needs of car designers to differentiate the product through imaginative lighting solutions. In this second part, extracted from just-auto's QUBE research service, we consider the regulatory framework and the advent of daytime running lights (DRLs) in Europe.

Historically, there has been a wide difference between the rules and regulations surrounding lighting applied in different parts of the world, although Europe has to worked to a centrally coordinated set of rules since the late 1950s.

Often countries have adopted rules similar to or the same as those applying in Europe. However, one major exception remains, namely the US. This means that vehicle companies have to design at least two sets of lights for global markets, one for North America and one for the rest of the world. In general, most countries will accept European compliant lights, although there are some unique settings and requirements in certain markets, such as Australia; these though are understood to be relatively easily met through adopting the European or North American specified lights as required. Japan used to have some unique requirements but these have been largely phased out.

Regulations will set out the performance requirements, in terms of light intensity, distribution and anti-glare performance in particular, for front, rear, reversing and other specific lighting functions. The EU has specific directives or rules for: reflex reflectors, side/rear/stop lamps, direction indicator lamps, rear registration plate lamp, headlamps and bulbs, front fog lamps, rear fog lamps, reversing lamps and parking lamps; in fact out of the 50 EC standards which a car has to comply with to get European type approval, eight of these standards relate specifically to exterior light functions. Moreover, there are specific directives applying to forward vision, rear visibility and lighting installation, meaning that more than one-fifth of EC directives are concerned with lighting and vehicle visibility in some way.

It is worth mentioning a couple of the ECE regulations specifically: ECE37 regulates the specifics of filament lights for cars and other road vehicles, while ECE R99 covers the rules on gas-discharge (HID Xenon) lights.

Differences in lighting regulations can affect vehicles which are offered for sale in some markets or prevent private imports from one part of the world to another. For example, although European specified lights are accepted in Canada, such vehicles cannot be sold on into the USA, which limits their second hand value; hence, most European-made models which are sold in Canada are in fact the US-specified models.

The US regulations do not currently allow the full functionality of AFS lighting to be fitted to vehicles sold there, to the arguable detriment of US consumers' safety, both drivers/passengers and pedestrians.

Europe's daytime running lights (DRLs)

In Europe, day time running lights (DTRLs or DRLs) are now mandatory but they are not required in the US - however, neither are they banned, so European brands sold in the US now almost invariably include DRLs, even though they are not required.

Daytime running lights (DRLs) are meant to draw attention to road-going vehicles during the daytime. They were first introduced in Nordic countries in the 1970s, and their adoption by other countries proceeded at a moderate pace in the following decades. DRLs have been required on all new vehicles in Canada since 1990, allowed on all vehicles in the US since 1995, and are now either permitted or required in many jurisdictions worldwide.

In February 2011, new EU rules came into force which made it mandatory for new vehicles to be fitted with daytime running lights (DRLs). The rule applied from that date to cars and small vans; the same rules applied to large vans, trucks and buses from August 2012. DRLs are turned on automatically when the engine starts and have been designed to consume much less power than dipped beam headlights. DRLs are said to consume less than one-third of the energy of a conventional driving light. The primary purpose behind this ruling is, according to the EU, to reduce accidents.

The EU says more than 35,000 people were killed on European roads in 2009 and, for every death there are an estimated four permanently-disabling injuries, ten serious injuries and 40 minor injuries. According to recent research on DRLs, road users, including pedestrians, cyclists and motorcyclists can detect vehicles equipped with DRL more clearly and sooner than those equipped with dipped beam head lights. On vehicles equipped with DRLs, the light is automatically switched on when the engine is started. When it is dark the driver has to switch on the driving lights manually. In this case the DRL goes off automatically. The energy consumption is approximately 25%-30 % of the consumption of a standard driving light. When using LEDs for DRLs, the energy consumption is further reduced to only 10%, according to the EU.

Meanwhile, North American standards continue to allow DRLs based on modified operation of headlamps; these have provoked glare complaints and safety problems due to drivers mistakenly driving with DRLs at night and in inclement weather, rather than with proper headlamps illuminated. Consumer reaction to high-glare DRLs, particularly in the US, has been negative to such a degree that anti-DRL groups have lobbied for DRL bans and organised boycotts of vehicle makers equipping their cars with high-glare DRLs. While these have not been entirely successful, they have in some cases done considerable damage to certain vehicle makers' publicly perceived safety reputations.

The effect of DRLs on fuel consumption and emissions has historically not been a significant concern in the North American market, where US Federal emissions and fuel economy test protocols permit the DRLs to be disabled during testing. This provision, however, may be withdrawn in the near future as new carbon emissions regulations are phased in. Therefore, low-power solutions are of definite interest from the regulatory standpoint in the NAFTA market. However, of arguably greater importance, styling issues will direct the level of interest in high-tech DRLs outside Europe. Audi uses curvilinear LED-array DRLs on high-end models worldwide, while the lower-specification models incorporate DRLs based on ultra long-life filament bulbs. Both systems are designed to present an immediately recognisable characteristic Audi face to all observers, though the high-spec LED units also telegraph the technical sophistication of the whole vehicle.

Audi's chief of lighting, Dr Wolfgang Huhn, has said: "LEDs are the logical light source for DRLs. Long durability, low consumption. All innovative car makers will use them. Every car maker has to find their own style." BMW and Mercedes have likewise adopted DRL solutions that meet all worldwide regulations, advertise the vehicle's brand identity while it is operating in daytime traffic, and show the specification and technology level of the car.

Automotive Lighting's Michael Hamm claims moreover: "About 64% of the car's statistical usage time, DRL is on. More and more car makers see the potential of giving a brand image at day and night to their cars."

For its part, Hella has developed an LED daytime running light, known as LEDayFlex. Compared to the use of conventional halogen daytime running lights, claims Hella, the use of LEDayFlex saves costs. The LEDayFlex is made up of individual LED modules which can be installed in different shapes as daytime running light chains. From January 2011 onwards, different versions with five, six, seven and eight module chains have been on sale, with the different ECE type-approved installation versions - and all the variants are available both with and without position light. The lights are switched on automatically when the engine is started up, and only go out again when the parking lights or the low beam are switched on, or the engine is switched off. If the light is also used as a position light, it changes to dimmed night-time operation.

In an interview with, UK aftermarket lighting specialist Astra Automotive suggested that, after the European Commission recently mandated the use of daytime running lights (DRLs) for newly-registered vehicles, European motorists could get stung if their light emitting diode (LED) bulbs fail because they may have to stump up the cost of replacing complete lighting units. just-auto asked Astra Automotive's Leon Callahan and managing director Robert Jones if the requirement for DRL spelt out good news for his company?

He told us: "The daytime running lights that we have seen are mostly LEDs, therefore this will not bring in new business for the replacement bulb market for at least three years, because in nearly all cases they will be covered under manufacturers' warranties.

"Even then, most will be fitted with LED model specific lighting systems such as the LED 'eyebrow' effect of the Audi and LED circle around the front side lights on the latest Land Rover and Range Rovers.

"These units, as we see it, will be sealed in manufacture so if an LED light was to fail, it will almost certainly be impossible to just replace the bulb. Instead the motorist will have to replace the whole light assembly, which will prove expensive in terms of replacement and garage time. The same goes for truck and bus operators who are more conscious of vehicle downtime and costs."

In addition to being expensive to replace, another concern among motorists is that the bright LED versions of DRLs can make flashing direction indicators in the same cluster harder to see under some conditions. Jaguar's solution: when the direction flasher comes on, the DRL on that side dims. This feature appeared on the 2012 model year XF. Indeed, the Jaguar XF has dimming DRLs and this was explained by Jaguar as follows: the dimming function is required to meet European legislation which gives vehicle manufacturers the choice of either dimming the DRLs when using directional indicators or for the DRLs to switch off when turning. In Europe, and indeed the rest of world (North America excepted), the dimming route has been chosen; in the USA, different legislation means that the DRLs are turned off when turning.   

See also: June 2014 management briefing: advances in lighting (1)