LEDs are being used with increasing frequency in car lamps. They offer very long service life, extreme vibration resistance, and can permit considerably shallower packaging compared to most bulb-type assemblies. LEDs also offer a significant safety performance benefit when employed in stop lights, for when power is applied they rise to full intensity approximately 200 milliseconds (0.2 seconds) faster than incandescent bulbs. This fast rise time not only improves the attentional conspicuity of the stop lamp, but also provides following drivers with increased time in which to react to the appearance of the stop lamps.

The commercial vehicle industry has rapidly adopted LEDs for virtually all signaling and marking functions on trucks and buses, because in addition to the fast rise time and concomitant safety benefit, LEDs’ extremely long service life reduces vehicle downtime. Almost all commercial vehicles use exterior lighting devices of standardised format and fitment, which has cost-reduced and sped the changeover. Traditional light sources required the engine to continue running to ensure that the battery would not get worn out if the lights were to be used for more than a few hours. The energy-efficient nature of the LED source allows the engine to remain turned off but the light to continue to flash.