Collision Avoidance Systems Act of 2019 This bill allows a passenger car, multipurpose passenger vehicle, truck, or bus to be equipped with a pulsating light system for high mounted stop lamps. The term "pulsating light system" means a system for a high mounted stop lamp in which (1) the lamp pulses rapidly no more than four times and for no more than two seconds when the vehicle brake is applied and then converts to a continuous light until the brake is released, and (2) the rapid pulsing may not be repeated upon a subsequent application of the brakes for a lock-out period of five seconds after the brake's release.