by FHWA staff writer
Source: Encyclopedia BritannicaGarrett Augustus Morgan, Sr. was an American inventor whose curiosity and innovation led him to develop several commercial products, the successors of which are still in use today. A practical man of humble beginnings, Morgan devoted his life to creating items that made the lives of common people safer and more convenient.
Among his creations was the three-position traffic signal, a traffic management device that greatly improved safety along America's streets and roadways.
Morgan's technology was the basis for the modern-day traffic signal and was a significant contribution to development of what we now know as Intelligent Transportation Systems.
Garrett Augustus Morgan, Sr. was born in Paris, Kentucky on March 4. . His parents were former slaves.
Morgan spent his early childhood attending school and working with his brothers and sisters on the family farm. He left Kentucky while still a teenager, moving north to Cincinnati, Ohio in search of employment.
An industrious youth, Morgan spent most of his adolescence working as a handyman for a wealthy Cincinnati landowner. Similar to many African Americans of his generation, whose circumstances compelled them to begin working at an early age, Morgan's formal education ended after elementary school. Eager to expand his knowledge, however, the precocious teenager hired a tutor and continued his studies in English grammar while living in Cincinnati.
In , Morgan moved to Cleveland, Ohio, where he worked as a sewing machine repair man for a clothing manufacturer. Experimenting with gadgets and materials to discover better ways of performing his trade became Morgan&#;s passion. News of his proficiency for fixing things traveled fast and led to numerous job opportunities with various manufacturing firms throughout the Cleveland area.
Morgan opened his own sewing equipment and repairs shop in . It was the first of several businesses he would start. In , he expanded the enterprises to include a tailoring shop, which retained 32 employees. The new company made coats, suits, and dresses, all sewn with equipment the budding inventor had made himself.
In Morgan started the Cleveland Call newspaper. As the years progressed, he became a prosperous and widely respected businessman. His prosperity enabled him to purchase a home and an automobile. Morgan's experiences driving through the streets of Cleveland are what led him to invent the nation's first patented three-position traffic signal.
Garrett A. Morgan&#;s illustration for his T-shaped traffic signal patent in .The first American-made automobiles were introduced to U.S. consumers shortly before the turn of the century. Ford Motor Company was founded in and with it, American consumers began to discover the adventures of the open road.
At that time, it was not uncommon for bicycles, animal-powered carts, and motor vehicles to share the same thoroughfares with pedestrians. Crashes frequently occurred between the vehicles. After witnessing a collision between an automobile and a horse-drawn carriage, Morgan was convinced that something should be done to improve traffic safety.
While other inventors are reported to have experimented with and even marketed their own three-position traffic signals, Garrett A. Morgan was the first to apply for and acquire a U.S. patent for such a device. The patent was granted on November 20, . Morgan later had the technology patented in Great Britain and Canada as well.
Prior to Morgan's invention, most of the traffic signals in use featured only two-positions: Stop and Go. Manually operated, these two-position traffic signals were an improvement over no signal at all, but because they allowed no interval between the Stop and Go commands, collisions at busy intersections were common during the transition moving from one street to the other.
Another problem with the two-position traffic signals was the susceptibility to human error. Operator fatigue invariably resulted in erratic timing of the Stop and Go command changes, which confused both drivers and pedestrians. At night, when traffic officers were off duty, motorists frequently ignored the signals altogether.
Source: [mstock]stock.The Morgan traffic signal was a T-shaped pole unit that featured three positions: Stop, Go and an all-directional stop position. The third position halted traffic in directions before it allowed travel to resume on either of the intersection's perpendicular roads. This feature not only made it safer for motorists to pass through intersections, but also allowed pedestrians to cross more safely.
At night, or at other times when traffic was minimal, the Morgan signal could be positioned in a half-mast posture, alerting approaching motorists to proceed through the intersection with caution. The half-mast position had the same signaling effect as the flashing red and yellow lights of today&#;s traffic signals.
Morgan's traffic management technology was used throughout North America until it was replaced by the red, yellow, and green-light traffic signals currently used around the world. The inventor eventually sold the rights to his traffic signal to the General Electric Corporation for $40,000. Shortly before his death in , Morgan was awarded a citation for the traffic signal by the U.S. Government.
In , Morgan received a patent on a Safety Hood and Smoke Protector. Two years later, a refined model of this early gas mask won a gold medal from the International Association of Fire Chiefs.
On July 25, , Morgan made national news for using his gas mask to rescue several men trapped during an explosion in an underground tunnel beneath Lake Erie. Following the rescue, Morgan's company was bombarded with requests from fire departments around the country that wished to purchase the new lifesaving masks. The Morgan gas mask was later refined for use by U.S. soldiers during World War I.
As word spread across North America and England about Morgan&#;s life-saving inventions, such as the gas mask and the traffic signal, demand for these products grew far beyond his hometown. He was frequently invited to conventions and public exhibitions around the country to show how his inventions worked.
The Federal Highway Administration honors Garrett Morgan&#;s contributions to making the world a better place, through programs like the Garrett A Morgan Transportation Technology Education Program, which helps K-12 students in science, technology, engineering, and mathematics to become &#;tomorrow&#;s transportation professionals.&#;
Traffic lights are signalling devices positioned at road intersections, pedestrian crossings, and other locations to control flows of traffic. The history of traffic lights is associated with the historic growth of the automobile.[1]
Traffic lights were first introduced in December on Parliament Square in London to reduce the need for police officers to control traffic.[2] Since then, electricity and computerised control has advanced traffic light technology and increased intersection capacity.[3]:&#;141&#;
Advert for an "Electric Traffic Regulator" in the Pryke & Palmer catalogue of The installation of a traffic signal in San Diego in December A traffic light in Stockholm in .[
edit
]
Before traffic lights, traffic police controlled the flow of traffic. A well-documented example is that on London Bridge in .[3] Three men were given the task of directing traffic coming in and out of either London or Southwark. Each officer would help direct traffic coming out of Southwark into London and he made sure all traffic stayed on the west side of the bridge. A second officer would direct traffic on the east side of the bridge to control the flow of people leaving London and going into Southwark.
On 9 December ,[4] the first non-electric gas-lit traffic lights were installed outside the Houses of Parliament in London to control the traffic in Bridge Street, Great George Street, and Parliament Street.[2] They were proposed by the railway engineer J. P. Knight of Nottingham who had adapted this idea from his design of railway signalling systems[5] and constructed by the railway signal engineers of Saxby & Farmer. The main reason for the traffic light was that there was an overflow of horse-drawn traffic over Westminster Bridge which forced thousands of pedestrians to walk next to the Houses of Parliament.[6] The design combined three semaphore arms with red and green gas lamps for night-time use, on a pillar, operated by a police constable. The gas lantern was manually turned by a traffic police officer with a lever at its base so that the appropriate light faced traffic.[7] The signal was 22 feet (6.7 m) high. The light was called the semaphore and had arms that would extend horizontally that commanded drivers to "Stop" and then the arms would lower to a 45 degrees angle to tell drivers to proceed with "Caution". At night a red light would command "Stop" and a green light would mean use "Caution".[3] Although it was said to be successful at controlling traffic, its operational life was brief. It exploded on 2 January as a result of a leak in one of the gas lines underneath the pavement[8] and injured the policeman who was operating it.[9]
[
edit
]
For more information, please visit FAMA.
In the first two decades of the 20th century, semaphore traffic signals like the one in London were in use all over the United States with each state having its own design of the device. One example was from Toledo, Ohio in . The words "Stop" and "Go" were in white on a green background and the lights had red and green lenses illuminated by kerosene lamps for night travellers and the arms were 8 feet (2.4 m) above ground.[3]:&#;22&#; It was controlled by a traffic officer who would blow a whistle before changing the commands on this signal to help alert travellers of the change. The design was also used in Philadelphia and Detroit.[3]:&#;23&#; The example in Ohio was the first time America tried to use a more visible form of traffic control that involved the use of semaphores. The device that was used in Ohio was designed based on the use of railroad signals.[1]:&#;382&#;
In , a traffic control device was placed on top of a tower in Paris at the intersection of rue Montmartre and the boulevard Montmartre. This tower signal was operated by a policewoman and she used a revolving four-sided metal box on top of a glass showcase where the word "Stop" was painted in red and the word "Go" painted in white.[3]:&#;33&#;
[
edit
]
In , the first electric traffic light was developed by Lester Wire, a policeman in Salt Lake City, Utah.[10] It was installed by the American Traffic Signal Company on the corner of East 105th Street and Euclid Avenue in Cleveland, Ohio.[3]:&#;27&#;28&#;[11][12] It had two colours, red and green, and a buzzer, based on the design of James Hoge, to provide a warning for colour changes. The design by James Hoge[13] allowed police and fire stations to control the signals in case of emergency. The first interconnected traffic signal system was installed in Salt Lake City in , with six connected intersections controlled simultaneously from a manual switch.[3]:&#;32&#;
The first four-way, three-colour traffic light was created by police officer William Potts in Detroit, Michigan in .[14][15] He was concerned about how police officers at four different lights signals could not change their lights all at the same time. The answer was a third light that was coloured amber, which was the same colour used on the railroad.[6] Potts also placed a timer with the light to help coordinate the lights. A tower was used to mount the lights as the junction at which it was installed was one of the busiest in the world, with over 20,000 vehicles a day.[3]:&#;35&#;
Los Angeles installed its first automated traffic signals in October at five locations on Broadway. These early signals, manufactured by the Acme Traffic Signal Co., paired "Stop" and "Go" semaphore arms with small red and green lights. Bells played the role of today's amber lights, ringing when the flags changed&#;a process that took five seconds. By the city had installed 31 Acme traffic control devices.[16]
[
edit
]
In traffic towers were beginning to be controlled by automatic timers. The first company to add timers in traffic lights was Crouse Hinds. They built railroad signals and were the first company to place timers in traffic lights in Houston, which was their home city.[1]:&#;385&#; The main advantage for the use of the timer was that it saved cities money by replacing traffic officers. The city of New York was able to reassign all but 500 of its 6,000 officers working on the traffic squad; this saved the city $12,500,000.[1]:&#;385&#; Wolverhampton was the first British town to introduce automated traffic lights in in Princes Square at the junction of Lichfield Street and Princess Street on a trial basis.[17] Great Britain's first permanent automated traffic lights were opened on 16 March in Leeds, on the corner of Park Row and Bond Street.[18][19]
The introduction of automated traffic signals required a change of behaviour for pedestrians. Most urban groups welcomed traffic lights; signals were seen by many as favourable to police officer control because they were not affected by potential human biases such as racism or mistrust of transit companies.[1]:&#;386&#;7&#; After witnessing an accident between an automobile and a horse-drawn carriage, inventor Garrett Morgan filed a U.S. patent for a traffic signal.[20] Patent No. 1,475,024 was granted on 20 November for Morgan's three-position traffic signal.[21]
A further development of traffic signals were staggered systems. These allowed the implementation of early green waves, so that vehicles travelling at a certain speed along a single street would only encounter green lights. The first staggered system was installed in on Sixteenth Street, Washington, D.C., leading to a doubling of commuting speed.[1]:&#;388&#;
The twelve-light system did not become available until and another feature of the light system was that hoods were placed over the light and each lens was sand-blasted to increase daytime visibility.[1]:&#;383&#; Both the tower and semaphores were phased out by . Towers were too big and obstructed traffic; semaphores were too small and drivers could not see them at night.[1]:&#;382&#;
Ashville, Ohio, claims to be the home of the oldest working traffic light in the world, used at an intersection of public roads from to when it was moved to a local museum.[22][23] Guinness World Records backed this claim by naming it the Oldest functional traffic light.[24]
In , the first traffic light in the continent of Asia was installed in Haifa, Israel.[25] The first traffic light in South India was installed at Egmore Junction, Chennai in . The city of Bangalore installed its first traffic light at Corporation Circle in .[26]
[
edit
]
The control of traffic lights made a big turn with the rise of computers in America in the s. Thanks to computers, the changing of lights made traffic flow even better thanks to computerised detection. A pressure plate was placed at intersections so that computers would know that a car was waiting at the red light.[3]:&#;135&#; Some of this detection included knowing the number of waiting cars against the red light and the length of time waited by the first vehicle at the red.[3]:&#;141&#; One of the best historical examples of computerized control of lights was in Denver in . One computer took control of 120 lights with six pressure-sensitive detectors measuring inbound and outbound traffic. The control room that housed the computer in charge of the system was in the basement of the City and County Building.[3]:&#;141&#; As computers started to evolve, traffic light control also improved and became easier. In , the city of Toronto was the first to use more advanced computers that were better at vehicle detection.[3]:&#;141&#; The computers maintained control over 159 signals in the cities through lines.[3]:&#;143&#;
Countdown timers on traffic lights were introduced in the s. Timers are useful for pedestrians, to plan whether there is enough time to cross the intersection before the end of the walk phase, and for drivers, to know the amount of time before the light switches. In the United States, timers for vehicle traffic are prohibited, but pedestrian timers are now required on new or upgraded signals on wider roadways. Some pedestrian timers can be used by motorists as well to know how much time remains in the green cycle, because often when the pedestrian timer reaches zero, the signal will simultaneously turn amber.[citation needed]
[
edit
]
When incandescent lamps began to replace gas-powered lamps, it was necessary to incorporate a coloured lens in red, yellow or green to produce the signals, as incandenscent bulbs can only shine white light. In France in particular, the units were equipped with a reflector and a different coloured lens of types such as Fresnel, prismatic or others.[27] This drawbacks of these were their short lifetime and a glare effect when the sun is shinning in colored lens. It was often impossible to identify which signal was in operation. As such, traffic lights have often since been equipped with visors.[28]
In the 's, new lighting source began to be deployed using a discharge tube. The patent of the Silec Society filed in explains this technology.[29] The advantages were that the light source did not need a coloured lens, and this technology resolved the glare effect, reduced energy consumption and lengthed the lifetime when compared with incandescent sources.[citation needed]
In , incandescent lamps were improved, with a lower 12V voltage, a better lifetime and reduced energy consumption.[30]
At the end of , the great turning point was the introduction of Light Emitting Diode (LED) lights, which benefitted from an even longer replacement cycle and lower energy use. The first LED main traffic light was put in service in in California. The system was created by Electro-techs in Corona (California), a company created by Raymond Deese in .[31]
[
edit
]
For more information, please visit 3m traffic light.