Adaptive Cruise Control (ACC) is one of the newest technologies of 2009, and it is slowly being offered in more and more models.  ACC is similar to conventional cruise control in that it maintains the vehicle's pre-set speed; the difference is adaptive cruise control (ACC) can also automatically adjust speed in order to maintain a proper distance between vehicles in the same lane. Also known as active or intelligent cruise control, it uses a radar and/or laser sensors (usually located behind the grille) to determine the speed and distance of the vehicle in front. If the lead vehicle slows down, the system sends a signal to decelerate to the engine or braking system. When the distance is computed to be safe again, the system accelerates the car back to its last speed setting.