LEDs are being used with increasing frequency in automotive leds . 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 brake 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 brake lamp, but also provides following drivers with increased time in which to react to the appearance of the brake lamps.

LEDs were first applied to automotive leds in Centre High Mount Stop Lamps (CHMSL), beginning in the early 1990s. Adoption of LEDs for other signal functions on passenger cars has been slow, but is beginning to increase with demand for the technology and related styling updates. The 2007 Audi R8 sports car uses two strips of optically-focused high-intensity LEDs for its Daytime Running Lamps. Optional on the R8 in ECE markets is the world's first LED headlamp made by automotive leds. The low and high beams along with the position (parking) lamp and front turn signal are all realized with LEDs. The Lexus LS 600h features LED low beam, position and sidemarker lamps in North America, and the 2009 Cadillac Escalade Platinum uses LEDs for the low and high beams, as well as for the position and sidemarker 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.

Automotive halogen lamps are a very common light source for headlamps and other forward illumination functions. Some recent-model vehicles use small halogen bulbs for exterior signalling and marking functions, as well. The first halogen lamp approved for automotive use was the H1, which was introduced in Europe in 1962.

Internationalized ECE regulations explicitly permit vehicle signal lamps with intensity automatically increased during bright daylight hours when sunlight reduces the effectiveness of the brake lamps, and automatically decreased during hours of darkness when glare could be a concern. Both US and ECE regulations contain provisions for determining the minimum and maximum acceptable intensity for lamps that contain more than a single light source.