A turn signal asks very little of the driver behind you: notice a blinking light for a moment and know which way the car ahead is about to go. Getting to that simple blink took more than half a century. A silent-film star built a signaling arm for her own car and never patented it. A New York inventor patented an electric system that no production car of the time used. It took Buick, a wave of state laws and, finally, the federal government to make one blinking light the signal every driver reads the same way.
- Silent-film actress Florence Lawrence built a signaling arm for her own car in 1914, plus a STOP sign worked by the brake pedal. She never patented either one.
- New Yorker Edgar A. Walz Jr. was granted a patent for an electric direction signal, with lamps front and rear, in 1915. No production car of the time used it.
- In 1939, Buick became the first American make to fit flashing turn signals as standard equipment, at the rear only. For 1940 it added front signals and a self-canceling lever.
- Most American makes did not follow until the 1950s, pushed by state laws. A revised federal standard, FMVSS 108, required turn signals on every new passenger car built from January 1, 1969.
An actress builds an arm
Florence Lawrence was one of the first film actors to be promoted by name, at a time when studios kept performers anonymous, partly because they feared fame would lead to demands for higher pay. Fans knew her as "the Biograph Girl" until 1910, when her new studio, IMP, began advertising her by name. Off the set she was a devoted motorist who could afford her own car when cars were still luxury items, and she liked to learn how they worked.
In 1914 she built a signaling arm for the back of her car. At the push of buttons by the driver's seat, it rose or lowered to show other drivers which way she was about to turn. A second device handled stopping: a sign reading STOP that flipped up at the rear when she pressed the brake pedal. Lawrence never patented either one, her mother's later attempt to patent them failed, and she received neither credit nor profit from them.
The patent nobody used
The same year Lawrence built her arm, a New Yorker named Edgar A. Walz Jr. applied for a patent on an electric direction signal. His system lit matching lamps at the front and rear of the car, switched by push buttons that could sit right on the steering wheel, and it added a second signal, usually a sound, so the driver could tell the lamps were working. The patent was granted in September 1915, but no production car of the time used it.
In Europe the answer stayed mechanical for decades. Trafficators, small arms shaped like a railway semaphore signal, swung out from the side of the car to point the way. They first appeared in the 1900s, never really caught on in the United States, and grew rare from the 1950s as flashing lights took over, though early Volkswagen Beetles, among others, still carried them.
Buick makes it standard equipment
In late 1938, Buick announced that its Flash-Way directional signal would be standard on every 1939 Buick, down to the least expensive Special. No American make had done that before. A small three-position switch on the column-mounted gearshift lever worked a pair of bulbs under red lenses beside the trunk-lid emblem, flashed 85 to 90 times a minute by a current interrupter from Tung-Sol. The signal worked only at the back of the car, and it did not cancel itself: the driver had to flip the switch back to center.
The following year, Buick fixed both problems. The 1940 system added signals at the front and moved the control to a small lever on the steering column with a self-canceling mechanism, which returned it to off once the wheel came back to center. Across General Motors that year, only Buick, Cadillac and LaSalle made turn signals standard; on Chevrolet, Oldsmobile and Pontiac they were an option of just under eight dollars.
From a Buick feature to a federal rule
The rest of the industry took its time. In January 1950, Automotive News estimated that only about a third of 1949 American cars had turn signals as standard equipment; on many others they were an option. States began to force the issue. Washington required turn signals on every vehicle manufactured after January 1, 1954, and by 1957 almost half the states had passed laws requiring them on new cars. That pushed the last holdouts: Chevrolet did not make them standard until 1956, Plymouth and Mercury until 1957. By the end of the decade, turn signals were standard on all or nearly all new American cars.
The federal government came last. The National Traffic and Motor Vehicle Safety Act of 1966 led to federal vehicle safety standards. FMVSS 108, the lighting standard, first took effect in 1968 for trucks, buses and other wide vehicles; a revision issued in December 1967 extended it to passenger cars and required turn signals on every new car built from January 1, 1969.
The blink keeps changing
The signal has changed in its details, not its purpose. Hazard flashers, which blink every signal at once, began as aftermarket accessories in the early 1950s. American carmakers moved most front signals from white to amber for the 1963 model year, and the 1969 federal standard made amber the only legal color up front. The sweeping, sequential signals on many new cars revive an idea Ford fitted to the Thunderbird from 1965. Bulbs have largely given way to LEDs, which switch on almost instantly, while a standard filament bulb takes about a quarter of a second to come up to near full output; in a 1993 University of Michigan lab study, drivers reacted to LED brake lamps about a sixth of a second sooner. And by the end of the 1990s, Mercedes-Benz was building a repeater of the signal into the side mirror, a common sight on new cars today.
None of that changes what the turn signal is for. It is still, as it was in 1914, a simple, courteous way to say: here's where I'm going. Florence Lawrence built one of the first versions and got nothing for it. Edgar Walz patented an electric one that no carmaker of the day put into production. It took Buick, a wave of state laws and a federal standard to turn the idea into the one signal every driver on the road reads the same way, whether or not everyone remembers to use it.
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Questions owners ask
Who invented the turn signal?
No single person. Mechanical signaling arms called trafficators appeared on cars in the 1900s. Silent-film actress Florence Lawrence built her own signaling arm in 1914 but never patented it. Edgar A. Walz Jr. of New York was granted a patent for an electric direction signal in 1915, but no production car of the time used it. Buick made flashing turn signals standard on its 1939 cars, the first American make to do so.
Did Florence Lawrence patent her turn signal invention?
No. She never patented her signaling arm or her brake-worked STOP sign, and her mother's later attempt to patent them did not succeed. Lawrence received no credit or profit from either invention.
When did turn signals become mandatory on cars in the United States?
Washington and other states began requiring them on new cars in the 1950s, and by the end of that decade they were standard on all or nearly all new American cars. The federal requirement came with FMVSS 108, the lighting standard issued under the National Traffic and Motor Vehicle Safety Act of 1966, whose revised version applied to every new passenger car built from January 1, 1969.
What was a trafficator?
A mechanical turn indicator: a small arm, shaped like a railway semaphore signal, that swung out from the side of the car to show which way it would turn. Trafficators first appeared in the 1900s, mostly on European cars, and grew rare from the 1950s as flashing lights took over. American cars moved to flashing lights instead, with Buick making them standard in 1939.
Sources (16)
- Florence Lawrence could afford her own car when cars were still luxury items, loved driving and learning how cars worked, and in 1914 built a button-operated signaling arm and a STOP sign that flipped up when the brakes were pressed. history.com
- Lawrence's arm sat at the back of the car's fender and rose or lowered at the push of buttons by the driver's seat; her stop sign was raised by pressing the footbrake; she never patented her inventions. lemelson.mit.edu
- Lawrence's mother later tried to patent her daughter's inventions and did not succeed. jalopnik.com
- Known as 'the Biograph Girl', Lawrence was among the early film performers identified by name by a studio, IMP, in 1910, at a time when studios kept actors anonymous partly for fear of demands for higher wages; she received no credit for, nor profit from, her automotive inventions. en.wikipedia.org
- Edgar A. Walz Jr. of New York applied in July 1914 for a patent on an electric direction-signaling system with matching lamps at the front and rear, push buttons that could be mounted on the steering wheel and an additional, usually audible, signal confirming the lamps worked; the patent (US 1,154,462) was granted September 21, 1915. patents.google.com
- Walz's electric turn signal was not installed on any production vehicle of its time; Buick was the first American automaker with standard turn signals, across its 1939 lineup. carbuzz.com
- Buick made its Flash-Way signal standard on all 1939 models, including the Series 40 Special; the 1939 system was rear-only, with bulbs under red lenses beside the decklid emblem, flashed 85 to 90 times a minute by a Tung-Sol current interrupter, switched from the column-mounted shift lever and not self-canceling; for 1940 Buick added front signals and a self-canceling column lever, and within GM only Buick, Cadillac and LaSalle made signals standard that year. curbsideclassic.com
- Automotive News estimated in January 1950 that directional signals were standard on about one-third of 1949 domestic cars; by 1957 almost half the states required turn signals on new cars; Chevrolet standardized them in 1956, Plymouth and Mercury in 1957; by late 1959 they were standard on all or nearly all new cars. curbsideclassic.com
- In 1940, turn signals were standard on Buick, Cadillac and LaSalle and an option of just under eight dollars on Chevrolet, Oldsmobile and Pontiac. zero2turbo.com
- Washington's 1953 session law required all vehicles manufactured after January 1, 1954 to be equipped with turn signals. bainbridgereview.com
- FMVSS 108, the federal lighting standard, first took effect January 1, 1968 for multipurpose passenger vehicles, trucks, trailers and buses 80 or more inches wide overall; a complete revision issued December 11, 1967 extended it to passenger cars, listing turn-signal lamps as required equipment, amber at the front and red or amber at the rear, effective January 1, 1969. govinfo.gov
- The American industry voluntarily adopted amber front turn signals on most vehicles from the 1963 model year. en.wikipedia.org
- Trafficators first appeared in the 1900s, their arm shaped after a railway semaphore signal, and have been increasingly rare since the 1950s; pre-1960 Volkswagen Beetles are an example of cars that carried them. en.wikipedia.org
- Hazard warning signals first appeared as aftermarket accessories in the early 1950s; sequential turn signals were factory fitted to 1965 to 1971 Ford Thunderbirds; Mercedes-Benz introduced turn-signal repeaters in the side mirrors at the end of the 1990s. en.wikipedia.org
- Standard incandescent brake lamps take about a quarter of a second to reach 90 percent of full output, and in a laboratory study drivers reacted to LED brake lamps about 166 milliseconds faster. backend.production.deepblue-documents.lib.umich.edu
- An informal count of 1,493 cars at six busy intersections in one European country found one luxury brand's drivers turned without signaling 19.3 percent of the time, against 11.4 percent for all other brands combined. discovercars.com
