High Intensity Discharge or HID lights can be recognized by their extremely bright white or bluish light. They provide better illumination than other types of lights.
HID lights improve visibility. Drivers using HID lights are able to see the road ahead for approximately 300 feet or 100 meters, compared to about 200 feet or 60 meters for a halogen system.
In comparison with halogen lights, HID headlights can be up to 3 times brighter, are more efficient in converting electrical energy into light energy, have a longer service life, and the light color is whiter or closer to daylight.
They operate on a gas discharge bulb system and consist of a light, bulb, ballast and special high voltage circuitry. HID headlights systems do not use a filament in the bulb. They have the inert gas Xenon inside the bulb, with two electrodes that have an air gap between them in a glass tube. A high voltage is applied between the electrodes. This causes an arc to form, which vaporizes the gases and solids so they emit a bright light. The voltage required to strike and maintain the arc is very high - typically up to 20, 000 volts.