Another technology aimed at reducing rear-end collisions is the so-called adaptive brake light. Basically, it strobes when you brake hard. Mercedes claims that its research shows a marked reduction in rear-end collisions when cars have the blinky brake lights, but the U.S. government stands unmoved; the system will be offered on all S-classes everywhere else in the world, but in the U.S., only a limited number of S600s with the technology will be sold because it isn't approved for widespread use.