A garment (e.g., vest) designed to be worn over a motorcyclist's outer clothing with high intensity LED lighting installed on front and rear surfaces thereof and motion-sensing circuitry and corresponding software that detects motorcycle deceleration and controls the sequence, color and/or intensity of the LED lighting. A small, light battery pack installed in the garment powers the system. The motion-sensing circuitry and software detects that the motorcycle is decelerating when the driver releases or reduces the throttle, downshifts and/or applies the brakes. Responsive to the driver releasing or reducing the throttle, downshifting, applying the brakes and/or riding on upward-directed terrain, the electronics and software change the color output of LEDs on the rear surface of the garment to red. The electronics of the garment are sealed in watertight assemblies.