A deceleration warning device for reducing rear-end collisions in road traffic includes a sensor for detecting a longitudinal acceleration value, a control device receiving the longitudinal acceleration value, determining an acceleration limit value, and generating a warning signal if the longitudinal acceleration value exceeds the acceleration limit value, and a rear lighting display for displaying an alarm state when the control device emits a warning signal. Determination of the acceleration limit value is based upon a plurality of signals including an anti-lock braking system (ABS) signal and a brake pedal position signal. The control device is operable in one of three levels depending upon a detected quality of the signals.