"Self-leveling Systems and Future Headlight Technology
Most adaptive headlights systems also include a self-leveling system. Self-leveling headlights have an additional level sensor that determines if the car is tilted forward or back. For example, if a car is driving over a large bump, when the front of the car hits the bump, it lifts up. Standard headlights would briefly point up into the sky until the rear of the car moved over the bump and the car returned to a level position. You may have noticed this if a car driving behind you at night passed over a bump, such as a railroad crossing. The other car's headlights would flash briefly, as if the driver had blinked his or her high beams at you. This is actually the car's headlights temporarily pointing up and into your eyes instead of down at the road. With a self-leveling system, electric servomotors react to the level sensor and keep the headlights aimed down at the road, no matter the position of the car.
Self-leveling headlights are already required on new cars in Europe, and they're required on all U.S. cars equipped with bi-xenon headlights. Bi-xenon lights are so bright that they would blind other drivers if they didn't level themselves.
Adaptive headlights aren't yet standard equipment on most cars. In fact, only a few companies even offer them as options. BMW offers optional adaptive headlights on all models, while 335, 535, 7-series and M-series include them as standard equipment. Renault offers them as an option on some models, and the 2006 Volkswagen Passat includes them in the optional Luxury Package. Lexus, Audi and many high-end manufacturers also offer adaptive headlight packages."
(source:
http://auto.howstuffworks.com/adaptive-headlight1.htm)
Auto leveling:
Latest evolution (introduced in July 2012): BMW Intelligent Headlight Technology: