Vehicle lighting systems are very important, particularly where road safety is concerned. If headlights were suddenly to fail at night and at high speed, the result could be catastrophic. In the automotive context, traditional headlights utilizing halogen and high-intensity discharge (HID) bulbs are often found in physically large formats, impairing both aerodynamics and aesthetics. Usually, this large format is caused by the reflector format and optics needed to focus the outputted light from the bulb in a certain direction. Headlights defined as auxiliary lights are no exception to this phenomenon.

To tackle these challenges in format, several manufacturers focus on techniques where LEDs are used as light sources instead of halogen or HID bulbs. In fact, LEDs are starting to replace the traditional light sources. The advantages gained from using LEDs instead of the earlier mentioned light sources are many; its lifespan is considerably longer, LEDs are more resistant to mechanical strain related to vehicles, the efficiency is better and above all is the possibility to produce smaller sized lights due to the compact shape of LEDs. However, all is not for the better, LEDs convert 75-80% of the input electric power to heat. This creates a demand for thought-out cooling and is the reason why most LED-technology headlights use several smaller and, in the context, weaker light sources instead of one strong like the halogen or HID light technology. This scenario where many smaller light sources are used instead of one powerful enables great flexibility when it comes to the format and looks of the auxiliary light. Lights utilizing LEDs can be found in many different shapes and sizes due to this fact.

Many techniques have been used, ranging from automatic changeover circuits to thermal circuit breakers, which pulse the lights rather than putting them out as a blown fuse would. Modern wiring systems fuse each bulb filament separately and even if the main supply to the headlights failed, it is likely that dim-dip would still work. Different application in the vehicle require different type of light sources and based on the application help designers to choose the final product , which provides aesthetics and usage of the light source.