Turn signals
Turn signals (US English: indicators is the British English term) is a set of lights on a vehicle (be it a car, truck, tractor, etc.) which serve to indicate that the driver is intending to turn in a specific direction soon.
According to the Smithsonian Institution, the turn signal was invented by 1929, but was not widely used on cars until 10 years later, in 1939.
Turn signals are required on all vehicles that are driven on public roadways in the United States and most other countries.
In Europe, and many other nations, turn signals are required to be an orange or amber color at both front and rear on all modern vehicles. In the United States and Canada, they may also be white at the front and red at the rear, and the same rear red lights may serve as tail lights, brake lights and turn signals.
Turn signal lights must also conform with a minimum and maximum brightness level (specified in law in units of candlepower), so that they neither are invisible nor serve to blind those who view them.
Sequential turn signals
Some models of American car in the 1960s and early 1970s had multiple rear turn signal lights which flashed in a sequence, instead of all at once. These were called sequential turn signals.
