Vehicles have had lights for well over a hundred years. Candles lit Horse-drawn carriages. The first cars, then called "horseless-carriages" were lit by gas lights. By 1908 electric lighting began to be used on motor vehicles. Red tail lights and yellow brake lights were in use by 1915. Sealed beam headlights were used starting in 1936. By 1940 turn signals were used. Before 1939, headlight design was not standardised. Between 1940 and 1956, all vehicles built in the U.S. were required to have 7’’ round headlights (sealed beams). As of 1956 and up, it became possible to install 4 headlights on 1 vehicle (2 lights per 1 side). In 1960 the first halogen lights were used on European cars and the technology came to the US by 1979. Replaceable car light bulbs were in use in the US beginning in 1983.