|
|
|
Headlights - Xenon: Also Known as HID (High Intensity Discharge) lights. Named for the inert gas they employ to amplify light produced by electricity jumping between two electrodes. HID lights don’t use a filament, as do incandescent headlights, and they tend to last two to three times longer. They also provide much more uniform intensity. Aim a set of xenon headlights at a wall, and you’ll see they define a sharp line at the top of the projected light pattern rather than the gradual fade common to conventional headlights. HID lights produce ultraviolet as well as visible light, which makes reflective highway signs glow more brilliantly.
| Most vehicles that employ xenon headlights include a provision to ensure that they don’t blind oncoming traffic, even if the trunk is weighed down, which aims the headlights higher. BMW and Mercedes-Benz use self-leveling technology in the lights themselves, and others have automatic leveling for the whole vehicle, which achieves the same goal. A switch on the dashboard of Infiniti’s Q45 allows the driver to select one of four headlight heights — an approach with a large margin for human error.
The blinding blue lights you see on today’s roads may in fact be copycats. Shortly after the first xenon lights appeared on select BMWs in 1993, aftermarket companies began cranking out blue headlight bulbs and accessory lights. The kind of person who wants to drive around with blue lights also wants to make sure you see them, and tends to aim them higher than other drivers appreciate. Most of these copycat bulbs are conventional incandescent bulbs with a blue coating or blue glass. Some include xenon gas for marketing purposes, but they still have a filament, not the gap-jumping arc. True HID lights operate on high voltages — 15,000 volts to jump the gap when first turned on and around 80 volts thereafter — so they require additional components, namely a type of transformer called a ballast. HID offroad-style accessory lights that come with a separate ballast are fairly common. Though rare, there are now true HID headlights that can be added to a vehicle not equipped with them at the factory. | |
|
|
|
| |
