Stop, tail, and turn lights help you let pedestrians and other drivers know where your vehicle is going. Steady-burning tail lamps designate the back of the vehicle, in motion and standing still. Stop lamps indicate the vehicle is slowing down or stopping. Turn signal lamps, when activated, flash on the side you are turning toward. Combination turn/tail and s/t/t lights are available. Vehicle lighting color, mounting, and operation rules are spelled out in FMVSS/CMVSS 108 and state regulations.