With the help of a laser or a radar sensor, the Adaptive Cruise Control (ACC) system recognizes preceding vehicles, calculates their speed and keeps the distance required by automatically acting on the brakes and/or engine power.
ACC can scan the area in front of the vehicle in order to determine the distance to the vehicle ahead. The information gathered by the sensors and/or radar is used to warn the driver if he/she is tailgating or to maintain an automatic safety distance to the vehicle by cutting engine power or activating brakes if necessary.
Some ACC systems can actually get the vehicle to a complete halt without any driver intervention in case they’re detecting an impending impact with the object in front of the car.