A collision avoidance system, or pre-crash system, uses small radar detectors, typically placed near the front of the car, to determine the car’s vicinity to nearby obstacles and notify the driver of potential car crash situations. These systems can account for any sudden changes to the car’s environment that may cause a collision. Systems can respond to a possible collision situation with multiple actions, such as sounding an alarm, tensing up passengers’ seat belts, closing a sunroof, and raising reclined seats.