Very Early Brake Lights (Oct, 1923)
WARNING LIGHTS FOR AUTOS LIKE RAILROAD SYSTEM
Protective lights for the rear of automobiles, patterned after the railroad system of red and green signals, are a recent development. When the machine is moving, a green light shows constantly, but when the brakes are applied, the green signal is extinguished and a red one flashes a warning to following motorists. Two sets of green and red lights are used, one set for daylight driving and the other for night travel, the former being more powerful so that they may be plainly seen in the sunlight. Interlocking shutters are provided for each pair of lights and the signal has two 1-inch red side lights.