A proportional brake light system having an LED display carried on a motor vehicle and capable of instantaneously warning motorists following from behind whether and how quickly the vehicle is likely to stop in response to an operator generated foot pressure being applied to the brake pedal shoe. The brake pedal shoe of the vehicle has a hollow interior, and an optical signal is transmitted along an optical transmission path extending therethrough. As the pressure applied by the operator to the brake pedal shoe is increased, more of the optical signal being transmitted along the optical transmission path is interrupted. A multi-stage comparator is responsive to an interruption of the optical signal so as to cause a corresponding number of LEDs from the display to be illuminated. The LEDs are arranged in a pair of linear arrays that are aligned in oppositely extending illumination paths, such that an identical number of LEDs from each array is simultaneously illuminated to create a highly visible bar graph display.