Because of their fast switching times and long life, LEDs have been used in cars and motorcycles as high-mounted brake lights and in trucks and buses as brake lights and turn signals for some time, but many high-end vehicles are now starting to use LEDs for all their rear lights. Besides the gain in reliability led´s have a styling advantages because they are capable of forming much thinner lights than incandescent lamps with parabolic reflectors. The significant improvement in the time taken to switch on and off (perhaps 0.5s faster than an incandescent bulb) improves safety by giving drivers more reaction time. It has been reported that at normal highway speeds this equals one car length in increased reaction time for the car driving behind. White LED headlamps are also beginning to make an appearance. Audi has adopted these very well and stylishly.