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Color Me Stop And Go: The History Of The Traffic Light

You see them hanging around, here and there. They’re everywhere, part of the landscape, it seems but you never really pay close attention to them until you blow through a red one.

Traffic lights. Webster’s defines them as “a set of automatically operated colored lights, typically red, amber, and green, for controlling traffic at road intersections and crosswalks.”

Without traffic lights, urban life would be a lot more chaotic than it is. No doubt bloodier, too.

Roman MilestoneRoman MilestoneTraffic lights as regulators of traffic flow evolved from road signs – those ubiquitous objects on the side of roads that provide essential, often useful, and frequently annoying information. Road signs, of course, came on the scene sometime after the development of roadways, which developed to accommodate vehicular and military traffic.                                                                             

The oldest constructed roads known are stone paved streets at Ur, between the Tigris and Euphrates rivers in present day Iraq, and date to around 4000 BC. All of our traffic signs trace their origins to Roman milestones. As the name suggests, these were usually large stone columns placed at intervals of one mile (occasionally portions of a mile) and contained directions and the distance remaining to Rome; the origin of the old saying “All roads lead to home.” 

In the middle ages, road signs evolved into multidirectional indicators that directed travelers to distant villages and towns, and sometimes included distances to specific destinations. Automobile traffic signs began appearing on roadsides not long after the introduction and proliferation of the automobile.

The red, green, and amber colors used by traffic signals are nature-based and have evolved from nautical right-of-way, and railroad usage.

Almost from the very beginning, Red has been the color of choice for “Stop.” Red, the color of blood, is considered a hot, or “dangerous” color. It elevates blood pressure, and heightens nervous tension. The shade of red used in most traffic signals contains orange hues to improve its visibility by individuals with vision issues, such as color blindness.

On a color wheel, Green is the polar opposite of red, and a seemingly natural choice for “Go.” Green is a calming and welcoming, and hence, inviting color. According to some sources, the use of green as a “go” signal for car traffic is a carryover from railroads, which adopted the color because white light was not sufficiently discernible during daylight hours. Like red, the color green in most traffic signals is enhanced. It includes some blue for the benefit of colorblind individuals.

Yellow, or amber, the color of “Caution,” is the most visible color in the spectrum. It can be seen from the greatest distance.

The world’s very first traffic light was installed for the benefit of pedestrians, not traffic and was inspired by the 1102 fatalities and 1334 injuries documented on London roads in 1866. Invented by John Peake Knight (1828-1886), a railway engineer from Nottingham, the signal was installed at the busy intersection of Great George and Bridge Streets near Parliament in London on December 10, 1868. It was based on railway signals then in use, and manufactured by Saxby and Farmer, a leading railway signal manufacturer. Mounted on a tall pillar, it featured three semaphore arms provided with red and green gas lamps for nighttime use, and was operated by a police constable. It was an instant success.

Unfortunately, the signal was destroyed just over three weeks later, on January 2, 1869, by an explosion caused by a leaky gas valve that resulted in the death of the police officer operating the device. Knight’s signal was declared a public safety hazard and ordered removed. It would be another 60 years, 1929, before an electrified variation of Knight’s traffic signal would be reintroduced to London streets.

The next chapter in the development of the traffic light took place in Chicago in 1910, when Earnest Sirrine introduced what is believed to be the first automatically controlled traffic signal. The device used two separate display arms that rotated on an axis between two fixed positions. The display arms were arranged as a cross with one display continually offset from the other by 90-degrees. In place of red and green lights, Sirrine’s “street traffic system” used the non-illuminated words “stop” and “proceed.”

Two years later, Lester Farnsworth Wire (1887-1958) – a detective with the Salt Lake City Police Department – invented a traffic light that used red and green lights. It was powered from overhead trolley wires. The following year, 1913, James Hogue received a patent for a manually controlled red and green-lighted traffic signal that was installed in 1914 at 105th Street and Euclid in Cleveland. Its big advantage lay with the ability of police and/or fire personnel to adjust the rhythm of operation as necessary in the event of emergency.

William Ghiglieri of San Francisco received a patent on May 1, 1917 for the first automatically operated traffic signal employing red and green colored lights that included an option to allow manual operation. Then in 1920, Detroit cop William Potts (1883-1947) invented electrically powered, hanging, automatic traffic lights to control four-way intersections. Potts signals were the first to include amber “caution” lights and were installed at several busy intersections along Woodward Avenue, still the Motor City’s main drag.

In 1923, Garrett Augustus Morgan Sr. (1877-1963) – the inventor of a “respiratory protective hood” that was the forerunner of the gas mask, and the first African-American to own an automobile in Cleveland OH – received a patent for a reliable and inexpensive manually operated signal. Shortly after being awarded the patent, Morgan sold his rights to General Electric for $40,000 (currently the equivalent of more than a half-million dollars). GE used the patent for protection in a failed effort to establish a traffic light monopoly.

Meanwhile around this time in Detroit, the home of Henry Ford and the Model-T, the first traffic tower in the US was installed at the intersection of Woodward and Michigan Avenues in 1917. As they began being used in other cities, the towers assumed a wide variety of shapes and sizes, but were generally big, tall, right in the middle of all the traffic action, and therefore, VERY visible. These traffic controlling structures were often manned, but not necessarily so, and were available with or without traffic lights.

Laying claim to the world’s oldest operating traffic light is the city of Ashville OH. The light in question controlled traffic from its installation at the corner of Main and Long Streets for about 50 years. Designed by Ashville resident Teddy Boor, the signal featured a slowly rotating hand that swept across the face of each light to let drivers know how much time remained before a light change. The signal was ordered removed in 1982 by the Ohio Department of Transportation, which ordered the then village to replace it with a standard traffic light.

While it is no longer controlling car traffic, the light is still operating, and directing foot traffic inside the Ashville Museum, where it is the most popular exhibit. According to officials, “there is plenty of foot traffic.” The light has also been featured on Oprah and An American Moment With James Earl Jones

In a related sidebar, the first automated pedestrian signs featuring a lighted “don’t walk” signal were installed in New York City on February 5, 1952.

And finally, what would be the point of having a car without driving endlessly around in search of parking spaces and metering devices?

Carlton Cole “Carl” Magee – an attorney, publisher, and United States Senator from New Mexico – was awarded a patent for the first parking meter in 1935. The company he founded, the Magee-Hale Park-O-Meter Company, continues to manufacture most of the parking meters in use in the United States.

The father of the parking meter is an attorney and member of congress? It figures.

 
Sources: About.com, AshvilleOhio.net, BBC, MarkTraffic.com, MunicipalSigns.com, OnlineUtah.com, Civil Engineering Magazine, June 2006, Vol 76, No. 6, pg. 70 , Signalfan.com, StraightDope.com, Suite101.com, TheVictorianst.com, Wikipedia, Yahoo! Answers

Michael Daisy
Invention History
InventorSpot.com