The Strange but True History of the Turn Signal

Jim Motavalli

Jim Motavalli | Oct 03, 2019

The actress Florence Lawrence, who died in 1938 (by her own hand), isn’t well remembered today, but she was responsible for a major automotive invention—the electrically operated turn signal. As if that weren’t enough, her mother, Charlotte Bridgewood, invented an early automatic windshield wiper, the Electric Storm Windshield Cleaner, in 1917.

The unlucky Florence Lawrence, star of stage, screen, and turn signals. (Wikipedia)

In 1910, Lawrence (signed to Biograph) was the first actress to get her name above the title. She was in more than 200 films, and by 1915 she was wealthy enough to afford her own car, which she loved—describing it as “almost human.”

Florence Lawrence, name above the title, in 1912.

Lawrence was also an inventor—like her mother, and like Hedy Lamar, who worked with the composer George Antheil to develop a guidance system for Allied torpedoes during World War II.

In 1915, Lawrence announced the debut of her “auto-signaling arm.” She said that “when placed on the back of the fender, can be raised or lowered by electrical push buttons.” The brake arm was designed to work automatically when the pedal was pushed.

The glamorous Hedy Lamar invented a guidance system for Allied torpedoes. (Wikipedia photo)

Pretty advanced! But despite her stellar early career, Lawrence had an unlucky second act. She didn’t file for a patent, got hurt in a fire, couldn’t find acting work, and took ant poison. Her last words: “I am tired. Hope this works. Good bye, my darling. They can’t cure me, so let it go at that.” She was 52. Maybe it wouldn’t have made any difference if she did get a patent, because Percy Douglas-Hamilton applied for and got one in 1907 for a device “indicating the intended movement of vehicles,” and we don’t remember him, either.

Despite these early efforts, it would be a while before turn signals were widely adopted. At first, motorists signaled their intentions by hand: An arm straight out meant a left turn, an arm (bent at the elbow) pointing up meant right. To slow down or stop (at least in the U.S. and Canada) the driver (or cyclist) extended an arm out horizontally, then angled the forearm down.

The Inter-State Auto-Signal from 1921. (National Museum of American History)

The energy-saving device was the “trafficator,” a more primitive version of Lawrence’s mechanical arm. These cable-operated devices—derived from the semaphore signals used on trains—first appeared in the early 1900s, with action that was either mechanical (the driver pushed the arm down) or pneumatic. In 1908, Alfredo Barrachini in Rome put lights in them that lit up when the arm was extended.

The Boston-based Naillik Motor Signal Company put electric motors in trafficators in 1918, effectively stealing Lawrence’s invention from three years before. By 1927, French and German inventors had built trafficators that combined a solenoid and electric lighting. The trafficator was still in use two decades later on British cars and early Volkswagen Beetles. Manufacturers were still skeptical that cars needed signal devices. American Model A Fords didn’t get trafficators, but they were original equipment on the company’s cars built in Germany.

Trafficators in a British Austin A30. The UK was very slow to adopt turn signals. Note rear-window sign warning motorists of "trafficators in use." (Wikipedia)

In 1925, Edgar A. Waltz, Jr. got a patent on a fairly modern turn signal but couldn’t get anyone interested in putting it on cars. The patent expired without any success.

Oscar J. Simler's hand-built turn signal, patented in 1929. (National Museum of American History)

The guy who gets at least some of the credit for the turn signal is Oscar J. Simler, whose hand-built prototype is in the National Museum of American History. According to the museum, “This turn signal was invented by Oscar J. Simler and patented in 1929. Aside from signaling turns, the device would signal for slowing when the brake was pressed, and signal a stop when the brake and clutch were both pressed.”

There were two arrows for left or right, and a “Stop” section that glowed with the brake pedal. In other words, turn signals and brake lights in the same cluster. Here’s his patent for an “interlocking and tripping switch for automobile signals.” The device was to “provide [the] means, some of which are automatic, for indicating when the vehicle is to slow or stop or is to be turned to the right or left.”

A 1938 Buick Special. Note torpedo-style turn signals on the front fenders. (Wikipedia)

In the late 1930s, Joseph Bell patented the first blinking light device. Flash forward to the 1938 Buick, which boasted the “Flash-Way Directional Signal,” aka the first flashing light turn signal. You’d expect that the new approach would have immediately been adopted industry-wide, but in fact turn signals didn’t become commonplace until the early 1950s. Remember the sequential three-bulb turn signals on early T-Birds? These days, we take these simple safety devices for granted, but people drove without them for 50 years.

Modern LED turn signals in a BMW 7-Series. (Wikipedia)


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