High Intensity Disscharge, there the proper xenon lights, most new cars have them now, the really bright ( often white with a tint of blue ) lights.
they have no filliment just a bulb full of nobel gas and a ballast pack, by passing a high voltage curent through the gas it gives of a much brighter light than normal hallogen bulbs. basicly they give better light whilst using less power than a normal 55w halogen headlight bulb
