A vehicle warning system and a method of modifying a vehicle is provided. The system is installable on a vehicle having a brake pedal operatively connected to a brake light mounted on a rear portion of the vehicle. In one aspect, the vehicle warning system includes a distance proximity sensor adapted for mounting on the rear portion of the vehicle and a controller operatively connected to the sensor. The controller is adapted to receive a brake signal when the brake pedal of the vehicle is depressed, which activates the controller to send a start flashing signal to the brake light. The sensor sends a stop flashing signal to the controller upon sensing a vehicle within a selected distance behind the vehicle.