Electric turn signals, or indicators, are now a standard feature of virtually all motor vehicles. They are essential for warning fellow road users of intended movements to avoid collisions. Before their invention, drivers had to rely on good old-fashioned hand signals to let others know when they intended to turn.
It is thought that the first automatic turn signals were patented in 1907 by an Englishman called Percy Seymour Douglas-Hamilton. His so-called "devices to indicate the intended movement of vehicles" were in the shape of hands to mimic the manual signals in use at the time. Some years later, in 1925, Edgar A. Walz Jr. obtained a patent for a modern turn signal, but car manufacturers at that time were not interested.
The first company to incorporate electric turn signals into a commercial car was Buick. They introduced the device in 1938 as a safety feature and advertised it as the "flash-way directional signal." The driver would simply flick a switch on the steering column, which would illuminate a flashing directional arrow on the rear of the vehicle. In 1940, Buick improved upon their design by introducing self- canceling turn signals.
Since then, the design and function of the electric turn signal has remained virtually unchanged. Most modern cars have indicator lights mounted at the front and rear corners, and occasionally at the sides. Another improvement is the introduction of amber lights, which allow the signals to be visible in bright sunlight. The signal is usually operated by a lever mounted on the steering column, with upward or downward movements activating right- or left-hand turn signals. The signals flash at a steady rate of between sixty and 120 per minute.
