audi adaptive cruise control
Audi Adaptive Cruise Control (or ACC) is an advanced cruise control system that includes the features of a normal cruise control along with a few new advances that make driving safer and more comfortable. The system works like a normal cruise control system but also varies your speed to ensure that you always maintain a constant safe distance between your vehicle and cars in front of you. The Adaptive Cruise Control does this by using a radar sensor to detect the distance between vehicles, and comes with a range of presets that allow you to change the space between vehicles, depending on driving conditions.
The system reduces driver intervention and can improve fuel economy by minimizing unnecessary braking and acceleration, though even with the ACC active the driver must pay attention to the road. If the system can't automatically slow the car sufficiently, it will give a signal to the driver, warning them to apply the brakes. The system does not react to stationary objects or oncoming vehicles and may not function correctly on winding roads or in rain, snow, or fog.