How were the earliest automatic traffic lights automated?

How were the earliest automatic traffic lights automated?



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The first traffic light was operated by a policeman in 1868 and it was the only way things worked for a while.

Modern traffic control systems are implemented with microcontrollers, networks and software.

But what are the first mechanisms that allowed to free the traffic police from the mundane task of directing the traffic?

Was there a sort of an electric or mechanical timer? If so, how did it work? How were the automatic traffic lights synchronized?

All solutions that predate digital electronics are welcome.


In 1910 Ernest Sirrine had patented an automated street-traffic system that used a motor and a set of gears and pulleys to rotate signs attached to an axis.

… The cam 13 is driven at a constant speed and at a rate to suit the estimated proper speed of street traffic, and is of such a nature as to operate the arms 11 at proper intervals, this operation of these arms being simultaneous as they are linked at 16. Each time the arms 11 are operated both arms 7 and 8 are rotated about their fixed horizontal axes, whereby one arm displays one signal and the other arm displays and opposite signal each time the arms are rotated.

From that description, I guess you could say the first automated traffic light system used a mechanical timer, not synchronized with other traffic lights, but displaying opposite signals on both sides.


Automation

The acetylene-gas illumination system, being fully automatic and reliable, enabled automatic lights to be operated early on. Its main use today is in buoys, which inherently have to operate unattended. Automation on a large scale, bringing considerable savings in operating costs, came after the advent of electrical equipment and technology and the demise of compressed-air fog signals. Unattended lights are now designed to be automatic and self-sustaining, with backup plant brought on-line automatically upon failure of any component of the system. The status of the station is monitored from a remote control centre via landline, radio, or satellite link. Power is provided from public electricity supplies (where practicable), with backup provided by diesel generators or storage batteries. Where solar power with storage batteries is used, the batteries must have sufficient capacity to operate the light during the hours of darkness. In tropical and subtropical regions, day and night are of approximately equal duration throughout the year, but in temperate and polar regions the days become longer and the nights shorter during the summer, and vice versa in winter. In these areas, solar power has to operate on an annual “balance sheet” basis, with excess charge being generated and stored in large batteries during the summer so that a reserve can be drawn upon in winter. Canada and Norway successfully operate solar-powered lights of this type in their Arctic regions.


The First Traffic Signal

Although the purpose of a traffic signal is to regulate the flow of automobiles, traffic signals came into existence long before automobiles were invented. The idea for developing traffic signals began in the 1800&rsquos, and on December 10, 1868, the first gas-lit traffic lights were installed outside the Houses of Parliament in London. This model was proposed by a British railway engineer, J.P Knight. It was implemented to control the traffic of horse carriages in the area, and to allow pedestrians to safely cross the roads.

The gas-fueled lights needed to be manually controlled by a police officer using semaphore arms. During the daytime, the semaphore arms would be raised or lowered by the police officer, signaling vehicles whether they should proceed or stop. At night, instead of arms, gas-lit red and green lights were used. Red signaled carriages to stop, and green meant proceed. Red was used to stop, as it represented danger or caution, whereas green was determined to be a more reassuring color in most cultures and also has a strong emotional correspondence with safety.

As these were gas-lit lights, there were some incidents of lights exploding at night and injuring police officers who were controlling them. Therefore, the gas-lit traffic lights were not entirely safe to use.


Competing patents

Following the accident, about four decades passed before traffic signals began to grow in popularity again, mainly in the United States as more automobiles hit the road. The early 1900s saw several patents being filed, each with a different innovation to the basic idea.

In 1910, Ernest Sirrine, an American inventor, introduced an automatically controlled traffic signal in Chicago. His traffic signal used two non-illuminated display arms arranged as a cross that rotated on an axis, according to Inventor Spot. The signs said "stop" and "proceed."

The first electric traffic light using red and green lights was invented in 1912 by Lester Farnsworth Wire, a police officer in Salt Lake City, Utah, according to Family Search. Wire's traffic signal resembled a four-sided bird-house mounted on a tall pole. It was placed in the middle of an intersection and was powered by overhead trolley wires. A police officer had to manually switch the direction of the lights.

However, the credit for the "first electric traffic signal" usually goes to James Hoge. A system based on his design was installed on Aug. 5, 1914, in Cleveland. Hoge received a patent for the system in 1918. (He had filed his application in 1913.) Hoge's traffic signal used the alternating illuminated words "stop" and "move" installed on a single post on each of the four corners of an intersection. The system was wired such that police and fire departments could adjust the rhythm of the lights in case of an emergency.

William Ghiglieri of San Francisco patented the first automatic traffic signal that used red and green lights in 1917. Ghiglieri's design had the option of being either automatic or manual.

Then in 1920, William Potts, a Detroit police officer, developed several automatic traffic light systems, including the first three-color signal, which added a yellow "caution" light.

In 1923, Garrett Morgan patented an electric automatic traffic signal. Morgan was the first African-American to own a car in Cleveland. He also invented the gas mask. Morgan's design used a T-shaped pole unit with three positions. Besides "Stop" and "Go," the system also first stopped traffic in all directions to give drivers time to stop or get through the intersection. Another benefit of Morgan's design was that it could be produced inexpensively, thus increasing the number of signals that could be installed. Morgan sold the rights to his traffic signal to General Electric for $40,000.

The first electric traffic light in Europe was installed in 1924 at Potsdamer Platz in Berlin, according to Marcus Welz, CEO of Siemens ITS (Intelligent Traffic Systems) US. The five-sided traffic light was mounted on a tower and was primarily manual with some automation, which only required a single police officer to manage. A replica now stands nearby and is a popular tourist attraction.

Pedestrian signals began to be included on traffic signals in the 1930s, according to the U.S. Department of Transportation. A "Walk/Don't Walk" signal was first tested in New York in 1934. It even used an upright palm to indicate "Stop."

John S. Allen, an American inventor, filed one of the earliest patents in 1947 for a dedicated pedestrian traffic signal. Allen's design had the pedestrian signal mounted at curb level. Allen also proposed that the signals could contain advertisements. In his application, he explained that the words "Stop" and "Go" could be followed by the word "for," which in turn would be followed by a brand name.


History of Traffic Lights: 100th Anniversary of the First Electric Traffic System

The 100<sup>th anniversary of the first electric traffic light system will be marked on 5 August.

It was installed on the corner of East 105th Street and Euclid Avenue in Cleveland, Ohio, and had red and green lights and a buzzer to provide a warning that the colours were about the change.

Traffic signals' birth in London

The idea for traffic lights began in the 1800s when a system was required to control the ever-increasing flow of horse-drawn traffic. In 1868, in London, a signal was installed at the intersection of George Street and Bridge street, near Parliament. This provided pedestrians a safe crossing.

The system installed – a semaphore – involved a tall post with moveable arms. When the arms were positioned sideways it meant stop. After dark, a gas light was lit at the top. The green tinted lens meant go, while red meant stop.

Signals were initially controlled by hand, with officers deciding when the signals should be changed according to traffic flow. They would blow a whistle to warn drivers that the signal was going to change.

However, this method turned out to be unsafe. In 1869, a traffic signal exploded following a leak in one of the gas lines below, severely injuring the policeman operating it. This led to the semaphore project being dropped in London.

America's evolves the signal system

In America, the semaphore system continued to be rolled out, with more and more motorists, carts and trucks travelling on the road. However, with more traffic officers found it was difficult to judge congestion.

Potsdamer Platz in Berlin, Germany, in 1925 with the traffic light tower in the centre. Hulton Archive

While some cities began installing traffic towers, allowing officers to have a higher view of the traffic, in Utah in 1912, policeman Lester Wire developed the first electric traffic light system with red and green lights.

Two years later, the first electric signal was installed in Cleveland. It was based on a design by James Hoge and allowed police and fire crew to control the signals in case of emergencies.

Four-way systems and modern day

In Detroit, William Potts – also a police officer – decided to do something about the increasing number of cars on the roads. He looked to adapt railroad signals to be used on streets and developed a system with red, amber and green lights. He made the first four-way three coloured traffic system, and it was installed on the Woodward and Michigan Avenues in Detroit in 1920. A year later there were 15 automatic light systems.

Over the next 10 years, many inventors came up with new ways to control traffic signals. Charles Adler Jr came up with a signal that detected a car's horn, while Henry A Haugh developed a detector that sensed the pressure of passing vehicles.

The first electric traffic lights to be installed in England were in Piccadilly Circus in 1926. Just over 60 years later traffic lights became the subject of an art installation near London's Canary Wharf.

'Traffic Light Tree' was created by French sculptor Pierre Vivant, who described its meaning: "The sculpture imitates the natural landscape of the adjacent London Plane Trees, while the changing pattern of the lights reveals and reflects the never-ending rhythm of the surrounding domestic, financial and commercial activities."


The First Traffic Light Invented – The History of Traffic Signals from London Explosions to Motor City, USA

1860’s: Traffic Lights Start with a Bang in London

Traffic jams are to city living what toast and jam is to breakfast. Long before motorcars, chaotic crowds made getting across town noisy, messy and dangerous.

Prior to automated traffic lights, pedestrians, bicycles, street cars, horses, and motorcars made for dangerously chaotic congestion.

When was the first traffic light installed?

The first traffic light invented was in London in the 1860's, but it was hardly recognizable—or effective. It had been adapted from the railroad signal system by a railway manager, John Peak Knight, in 1868. The railroads used red gas lights at night to signal stops and green gas lights during the daytime. Knight installed a similar gas light, semaphore system at near London’s Westminster Bridge in December of 1868.

The life of the first traffic light signal was short lived. A gas leak caused one of the signal lights to explode on its police officer operator within a month of being installed.

Early semaphore signals had arms that read "stop" and "move", or other variations. They were not standardized. Some were automatic, some manual.

Automating traffic signals stalled after the London incident. Forty years passed before cars crowding city streets urged the development of traffic lights in the United States. London would not see another traffic light until 1929.

Early 20 th Century: Crowding Cities and American Sprawl Shine a Light on Traffic

The United States is a car culture like no other country. Unlike most European cities that started urban planning when horses were high-tech, many cities in the United States were designed around urban sprawl, suburban tracts, and motor cars.

John Peak Knight’s explosive gas traffic light was designed to coordinate London’s 1868 traffic—pedestrians, horses, and carriages. Congestion was a real problem, but the urgency of traffic control would build as city streets filled with faster, more dangerous motor vehicles.

In the early 1900s, the rush for traffic signals blossomed again. By the early 20 th century, several patents were underway.

1910-1920s: The Evolution of the Traffic Light

As traffic and cities grew, so did the race to solve growing traffic problems. The first traffic signals were semaphores. Semaphores are towers with moving arms signaling for traffic to stop or go. They could be manual or automatic. There was no consistent design. Various models were invented and put into place in cities as the need arose.

Traffic direction used to require police officers to stand in busy intersections.

1910: The automated signs of Chicago.

In Chicago, automated signal signs were introduced in 1910. They didn’t light up, but they did create clear indicators for traffic to “stop” or “proceed” according to the labeled arms.

1912: Birdhouse red and green light signals ascend on Salt Lake

In 1912, Lester Wire was a police officer exhausted by traffic at Main Street and 200 South. He developed a manually switched stop light. The four-sided box, raised on a ten foot pole, looked like a birdhouse and was operated manually by an officer. The officer would flip a switch to change between the dipped red and green lights.

1914: The first manually controlled electric signal comes to Cleveland

Like the 1910 semaphore, the first electric signal used words. However, the words were no longer written on arms that raised and fell. The words “stop” or “move” were on lights. The posts lit up on each of four corner-posts around an intersection. It was not automated, though. A booth with an operator was required to flip the switches.

The system allowed police officers to move from the middle of the street to a corner. From that vantage, an officer could oversee the crowd. If an emergency vehicle came, the officer could flip a switch and clear the intersection by triggering all red lights. The emergency vehicle could now pass effortlessly.

1917: The first automated red and green electric light system stuns San Francisco

Finally, in San Francisco the first red and green electric light system that could be operated automatically (or manually) was introduced in 1917.

1920: The roaring yellow light

In 1920, the first three-color light system was introduced in Detroit—aka Motor City, USA. The evolution of traffic light signals could not have a more appropriate context than Motor City. Ford Motor Company was founded in Detroit in 1903 (and other motor companies followed). Ford made cars affordable for more common people, rather than the wealthy, by creating larger scale factory production.

Ford's Model T (1921)
Factory production made for a new era of car ownership.

Stop and go were insufficient for the new volumes of cars zooming through intersections. Streets were full of new numbers of cars in addition to delivery wagons, bustling crowds, bicycles, horse-drawn carriages, and street cars. The introduction of the cautionary yellow light helped increase driver safety, decreasing accidents that come from running red lights.

General Motors Headquarter's in Motor City, USA

(Stop lights were incredibly important in chaotic city streets. Crosswalks weren’t even introduced until 1951. The first pedestrian fatality in the United States was in 1899.)

1923: Three-position traffic signals get patented

The development of the modern traffic light may have started in London, but it grew up in the United States. In Cleveland, an African American inventor named Garrett Morgan came up with an affordable, patented traffic signal. The yellow light made intersections safer than the old stop and go system. The new design was inexpensive enough that it allowed the installation of a lot more lights.

Morgan sold the patent to General Electric—and the spread of the traffic light was green lighted.


HistoryLink.org

On April 21, 1924, Seattle's first automatic traffic light begins part-time operation at 4th Avenue S and Jackson Street. Seattle is actually somewhat late to this party, as traffic lights have been operating in other American cities for as long as a decade. The light proves to be a great success, and they soon will sprout all over the city.

Seattle Sees the Light

The dawn of the automobile in the early twentieth century quickly created a need for traffic control in downtown Seattle intersections. In the earliest years a police officer controlled an intersection with hand signals. Later, Seattle police officers manned semaphore signals in busy intersections, manually turning the pole as needed to direct the flow of traffic. At night a floodlight lit up the officer so people could see him. The problem with this (aside from the obvious danger of getting hit by a car) is that the policeman couldn't pursue or otherwise handle traffic scofflaws. If he left his post to deal with an offender, traffic at the intersection usually descended into chaos.

Seattle was progressive in a lot of ways in the 1920s, but traffic control wasn't one of them. As early as 1912 rudimentary red and green lights mounted on a homemade wooden box were used in Salt Lake City. The first generally accepted electric traffic light was introduced in Cleveland in August 1914. In 1920 the first hanging traffic light, the four-way, three-light signal (and the first traffic signal with a yellow caution light) that we know today, debuted in Detroit. Many American cities had traffic lights before Seattle, but in the spring of 1924 the city saw the light.

The Department of Streets and Sewers ran traffic checks at Seattle's busiest intersections and came up with three candidates for Seattle's first traffic light: 4th Avenue S and Jackson Street, 4th Avenue and Pike Street, and Roy Street and Westlake Avenue. The intersection at 4th Avenue S and Jackson Street was chosen. Of the three, it was the easiest location to install a traffic light at, and there were no other intersections nearby that had traffic police who might inadvertently interfere with the traffic flow at 4th and Jackson. With 24,000 cars passing through the intersection on an average day between 7 a.m. and 10 p.m., the location was the right spot for the light. Planners scheduled a 30-day testing period.

Three Lights and a Gong

A squat iron post was mounted in the center of the intersection, topped by a box rigged with electric lights behind colored glass. In addition to the colors -- red, amber, and green -- a corresponding message, "stop," "traffic change," and "go," appeared on the face of the glass itself. (The messages were to better educate the public about the colors, but they apparently caught on easily enough.) A gong preceded each traffic change but it was hard for motorists to hear, especially when traffic was heavy. Timing of the light in either direction could be adjusted for the flow of traffic, and in this case the optimum timing for the green light was found to be 35 seconds north-south on 4th Avenue and 25 seconds east-west on Jackson Street.

The light began operating on the afternoon of Monday, April 21, 1924, running only during the afternoon and early evening during its first weeks of operation. Testing exceeded expectations. Traffic began clearing up at the intersection by 5:45 p.m., a full half-hour earlier than what the norm had been before the light was installed, and accidents there dropped dramatically. The automated signal was so successful that the police officers monitoring it never used the manual controls during the testing period, and within weeks downtown drivers successfully lobbied to have it turned on during the morning rush hour.

Seattle Office of Arts & Culture
King County

Sketch of Seattle's first automatic traffic light, Seattle Post-Intelligencer, April 20, 1924


Red Means Stop! The Curious History of Traffic Lights

Everyone is familiar with the red, yellow, and green stoplights at busy intersections keeping the traffic flow going smoothly, but did you ever wonder how they came to be in all of our cities and towns?

Long before people were driving automobiles, horse-drawn wagons were clogging up intersections, and it was becoming dangerous for pedestrians. According to the BBC, John Knight, a manager in the railroad industry, suggested using the same type of device the trains used.

The railroads used a box with a small sign that flipped between stop and go and was lit up at night by a nearby gas lamp. The only drawback was that someone had to operate it manually. The first light was put up at Bridge Street and Great George Street in Westminster, London, in 1868.

The signal worked well, and Westminster was discussing getting more. Just a few weeks later a gas main leaked and caused the light to explode, injuring the man stationed to operate the signal. The installation of more lights was scrapped.

In 1896, with the introduction of the automobile to the public, the idea of traffic lights was revisited. By this time there were several men working on plans for traffic lights.

The First Electric Traffic Light in Bucharest

According to Google’s digitized patent records, Ernest E. Sirrine filed patent number US976939A on April 4, 1910, for a Street Traffic System that used signs that would flip up or down, like the signal in England, but would do so automatically on a timer. It was first used in Chicago that same year.

In 1912, Lester Farnsworth Wire of Salt Lake City, Utah was appointed to head up the first traffic division in the city. Wire took his job very seriously and decided that, instead of officers standing out in the elements directing traffic, he would design an electric traffic signal.

A traffic light in Stockholm in 1953.

There were only red and green lights and the box was placed on a tall pole right in the middle of the intersection. It was powered by the electric trolley lines above. At first, an operator was still needed to stand in the weather and flip the switch, but in 1914 Wire added an enclosed platform for the operator.

The only problem was that the light boxes looked like birdhouses, which either amused or annoyed the townspeople. Local kids often vandalized the boxes. Wire had waited too long to file his patent and was unable to do so.

The installation of a traffic signal in San Diego in December 1940

James Hoge of Cleveland, Ohio won the patent rights to the electric stoplight with his independent design in 1913. Patent number US1251666A was awarded on September 9, 1913. His lights lit up the words “stop” and “move” and were installed in Cleveland in 1914. Hoge’s lights were the first that could be paused when emergency vehicles needed to get through.

In 1917 William Ghiglieri of San Francisco patented the first light that used solid red and green lights.

Traffic light in Israel Photo by פוטו ארתור (אברהם) רוסמן CC BY 2.5

Detroit policeman, William Potts, also used the railroad signal system as a basis for his design, but he added the yellow caution light we see today. Potts’ light was installed at Woodward and Michigan Avenues, and the city bought fifteen more.

Another Clevelander, Garrett Morgan, patented the fully automatic three-light traffic signal in 1923. His invention was bought by General Electric for forty thousand dollars. General Electric was able to retain the monopoly, and the traffic light evolved into what it is today.

The “walk” signal for pedestrians came about in the 1930s and was tested in 1934 in New York. In 1947, John S. Allen filed patent number US2503574A for his design which included the possibility of adding advertisements.

Tests are currently being done with “smart” technology allowing traffic signals to sense the traffic flow and adjust accordingly.


History of Automotive Headlamps - From Acetylene to LEDs

We can hardly imagine a car without headlamps nowadays, as driving an automobile during night without these now-mandatory parts is surely impossible. However, there were times when people actually drove vehicles without headlamps (sure, they weren't actually "real" vehicles and only a few of them were in fact powered by combustion engines). As time passed by, technology evolved and headlamps became mandatory in all countries across the globe, something that reduced the risk of accidents. According to the United States National Highway Traffic Safety Administration ( NHTSA ), approximately half of deadly accidents occur during night, despite the fact that night driving accounts for only 25 percent of overall traffic in the US.

The first vehicle headlamps were officially introduced during the 1880s and were based on acetylene and oil, similar to the old gaslamps. In essence, these two substances were used to fuel the headlamps but, due to the high costs of both oil and acetylene, improving the existing systems was fairly impossible. Although they were often praised for their resistance to currents of air and tough weather conditions such as snow and rain, they were soon replaced by electric lamps.

The first electric headlamp was produced by the Electric Vehicle Company based in Hartford, Connecticut in 1898 but, just like the previous systems, they had numerous disadvantages that blocked companies from adopting and improve it. For example, filaments implemented inside the electric headlamps could be burned pretty fast, especially when traveling during difficult conditions. Moreover, the early system demanded small energy sources which, again, demanded more investments and high costs that nobody could support at that time.

This didn't stop Cadillac from rolling out the first modern electric headlamp system in 1912, a new assembly which, compared to its predecessors, could be used even during rain or snow without the risk of getting burned.

Guide Lamp Company was the first company to introduce the low beam headlights in 1915 but, since most systems required drivers to step out of the car and turn on the lights manually, Cadillac developed its own assembly activated by an interior-mounted lever controlling the exterior lights. But even so, the first modern light bulb, incorporating both the low and the high beams, saw daylight in 1924, being followed by a foot-operated dimmer switch invented three years later.

The first halogen headlamp was officially unveiled in 1962 in Europe and became mandatory in several countries except the United States that used non-halogen sealed lamps until 1978. However, thanks to their capability of producing more light than traditional lamps using almost the same amount of power made halogen headlights the most popular around the world, with most automakers still using them on their latest models.

A couple of car manufacturer, however, slowly migrated to high-intensity discharge systems, also known as xenon headlights, which are said to provide even more light than halogen units. The first model to implement such a system was the 1991 BMW 7 Series.

Last-generation models incorporate even a more advanced system compared to HID , this time based on LEDs. Unfortunately, but, due to high costs of research, development and engineering, companies are still in doubt whether to migrate to this kind of headlamps.

Enough with the history, let's see some other interesting subjects related to headlamps.

Daytime running lights for instance are a bit different lighting devices mounted near or close to regular headlamps and are especially supposed to be used during daytime, no matter the weather conditions or other factors. This type of lights allows other drivers on the road to better notice an incoming vehicle, especially on highway or country roads.

The first countries to impose strict regulations regarding daytime running lights where those located in Scandinavia. Sweden was the first nation to adopt special laws in 1977, followed by Norway in 1986, Iceland in 1988 and Denmark in 1990. Finland made daytime running lights mandatory on all roads in 1997.

In the United States, however, daytime running lights caused controversy between automakers and state departments. General Motors, for instance, demanded the United States Department of Transportation to make the lights mandatory across the country while the US officials expressed their concerns related to the safety and glare produced by this kind of lights. Following long negotiations between carmaker, on one side, and state authorities, on the other, the daytime running lights finally received the green light in 1995. Automakers rushed to equip their models with this technology, with General Motors among the first companies to offer daytime running lights. At this time, a large percentage of the cars sold in the US feature daytime running lights.

Even though they are often regarded as safety-enhancers, daytime running lights have always caused controversy around the world. European regulators, for instance, raised questions regarding the way daytime running lights alter fuel economy and CO2 emissions. The lights are powered by electric power which, in its turn, comes from the engine. In order to produce electric power, the engine need fuel, hence fuel consumption and CO2 emissions.

Getting back to xenon headlamps, all high-intensity discharge lights require a ballast, including an ignitor, which controls the current sent to the bulb. The ignitor comes as a stand-alone element in D2 and D4 systems and as bulb-integrated elements in D1 and D3 assemblies.

Compared to the other types of headlamps, xenon units provide way more light, obviously improving visibility when driving during night. More importantly, the estimated life of a xenon light is 2000 hours, much more than halogen lamps (between 450 and 1000 hours).

However, don't imagine that using high-intensity discharge lights is only milk and honey. First of all, xenon lights produce considerably more glare than the other types of headlamps. Secondly, all systems have to be equipped with headlamp lens cleaning systems and automatic beam leveling control, with both measures especially aimed at reducing the amount of glare produced by these lamps. Last but not least, xenon is way more expensive than any of the other types of lights, counting here both the purchase and the install process (without mentioning the repair process that is often covered by warranty costs).

Automakers around the world have created wide range of very advanced technologies related or connected to vehicle headlamps.

The Advanced Front-Lighting System, also called as AFS , is currently installed on models produced by Toyota, Skoda and several others (most automakers prefer to use their own names although, in essence, the systems are based on the same principles). The AFS is basically a high-end technology relying on a series of factors, including steering angle and a number of sensors, to determine the driving direction and slightly adjust the front-lighting systems direction. A few prototypes rely on GPS and navigation details to anticipate road curves and adjust the lighting directions before entering a curve.

In addition, numerous automakers installed lights sensors to determine the moment the driver needs the lights (such as in tunnels and even during night) and automatically turns on the headlamps without driver assistance.

There is way more information to share about headlamps but, in essence, this should be it. Before ending this article, here are a few "did you know" facts related to headlights:

. in 1961 automakers aimed to use rectangular headlamps but they were prohibited in the US?
. the first 7-inch round sealed beam headlamp saw daylight in 1940?
. the first halogen light was designed by European companies in 1962?
. the 1996 Lincoln Mark VIII was the first American model to feature direct current xenon?
. foglamps were officially rolled out in 1938 on Cadillacs?
. Cadillac's "Autronic Eye" was the first automated system switching between lo and high beams in 1954?
. hidden headlamps first appeared in 1936 on the Cord 810 model?


Automated Red-Light Enforcement

The first red-light camera bill was signed in New York City in 1993 after several years of testing (Retting, 2010). Since then, many states and local jurisdictions have adopted red-light cameras, known along with speed cameras as automated enforcement.

At intersections with traffic lights, automated cameras take photographs of vehicles entering the intersection on a red light. Citations are sent to the vehicle&rsquos registered owner. [FHWA&rsquos] Red-Light Camera Systems Operational Guidelines (FHWA, 2005) provides information on red-light camera program costs, effectiveness, implementation, and other issues. Maccubbin, Staples, and Salwin (2001) provide more detailed information on programs operating in 2001. (UNC Highway Safety Research Center, 2011, p. 3-12)

Red-light cameras are used extensively in other industrialized countries. . . . [As of December 2011,] [a]ccording to the Insurance Institute for Highway Safety, red-light cameras are used in nearly 500 United States communities in 25 States and the District of Columbia. . . . Information on States&rsquo laws authorizing or restricting use of automated enforcement is provided by the GHSA ([2014c]) and by IIHS ([2014b]). (UNC Highway Safety Research Center, 2011, p. 3-12)

Effectiveness

The effectiveness of red-light camera programs has been a source of controversy in the research community. The methodologies used to assess effectiveness have varied, as have the conclusions drawn from different studies.

In one review of the literature, the UNC Highway Safety Research Center, 2011, p. 3-12, concluded that red-light cameras

increase rear-end crashes, reduce side-impact crashes (the target [crash type]), and reduce overall crash severity 40 ([Aeron-Thomas and Hess, 2005] [Decina, Thomas, et al., 2007] [Maccubbin, Staples, and Salwin, 2001] [McGee and Eccles, 2003] [Retting, Ferguson, and Hakkert, 2003] [Peden et al., 2004]). Because there tend to be increases in lower-severity rear end crashes that somewhat offset reductions in the target group of higher-severity [right-angle] crashes, cameras were found to be more beneficial at intersections with a higher ratio of angle crashes to rear-end crashes. Intersections with high total volumes, higher entering volumes on the main road, short signal cycle lengths, protected left turn phases, and higher publicity may also increase the aggregate cost benefits of red light camera enforcement ([Council et al., 2005]).

Several additional studies also found positive results in red-light camera studies. Hu, McCartt, and Teoh, 2011, analyzed data on fatal crashes from 14 large U.S. cities with red-light camera enforcement programs and 48 cities without camera programs for the years 1992&ndash1996 and 2004&ndash2008. The average annual citywide rate of fatal red-light&ndashrunning crashes declined for both groups, but the rate for cities with camera enforcement declined more (35 percent versus 14 percent). During 2004&ndash2008, the rate of fatal red light running crashes citywide and the rate of all fatal crashes at signalized intersections were 24 percent and 17 percent lower, respectively, than what would have been expected without cameras. By examining citywide crash rates for cities with camera programs and using similar control cities, the study accounted for two common weaknesses of red-light camera research: regression to the mean and spillover effect.

Another study focused on red-light citations at the intersection with the highest incidence of traffic crashes in Louisiana following the installation of red-light cameras (Wahl et al., 2010). Over the eight-month study period, the researchers found a significant and sustained reduction in the mean number of citations per week (from 2,428 violations per week to 356 citations per week) and a nonsignificant reduction in collisions (122 to 97, p = 0.18) at the one intersection.

Two other studies also found positive results, although their research designs were not as strong. Newman, 2010, presented findings at the Institute of Transportation Engineers (ITE) 2010 Annual Meeting and Exhibit on the effectiveness of 16 red-light cameras at the busiest intersections in Springfield, Missouri. Following an extensive public education campaign and the installation of the cameras, there was a 20.5-percent reduction in right-angle collisions at photo-enforced signals. There was also an 11.4-percent increase in the number of rear-end crashes, although this increase was not as large as the 15.8-percent increase at the citywide level. Matched control intersections were not used in this study. A thesis from a James A. Baker III Institute research project using seven years of data from 50 intersections in Houston, Texas, concluded that red-light cameras reduced the monthly number of collisions by approximately 28 percent at intersections with a single camera. Installing two cameras per intersection resulted in reductions in collisions coming from all directions, even the two approaches that were not monitored with cameras (Loftis, Ksiazkiewicz, and Stein, 2011).

Other research has found effects in the opposite direction. Burkey and Obeng&rsquos, 2004, analysis of 303 intersections in Greensboro, North Carolina, over a 57-month period found a 40-percent increase in total crash rates resulting from increases in the number of rear-end crashes, sideswipes, and collisions involving cars turning left on the same roadway. They found no decrease in severe crashes (those that included fatal, disabling, and nondisabling injuries) and a 40- to 50-percent increase in possible-injury crashes (those reported in police records as possibly causing injury). Another study examined seven years of data from camera programs in five jurisdictions in Virginia and found a significant 18-percent increase in injury crashes (Garber et al., 2007). In addition, another group of researchers replicated a frequently cited study by Retting and Kyrychenko, 2002, found no significant effect at the p = 0.05 level, and concluded the original authors had incorrectly reported a reduction in crashes after the installation of red-light cameras (Large, Orban, and Pracht, 2008).

A recent meta-analysis found favorable results for red-light cameras only in studies with weaker research designs (Erke, Goldenbeld, and Vaa, 2009). Results of the meta-analysis showed a 15-percent increase in total crashes, a 40-percent increase in rear-end collisions, and a 10-percent decrease in right-angle crashes, although none of these results was significant. The author concluded that red-light cameras may have limited effectiveness however, others have countered that their analyses overweighted non&ndashpeer-reviewed studies (Lund, Kyrychenko, and Retting, 2009).

The studies reviewed used a variety of methodologies, data sources, time periods, comparisons, and metrics to reach their conclusions, so it is difficult to compare them directly. However, it does seem that it is premature to conclude that red-light cameras have been widely found to be highly effective.

Measuring Effectiveness

Effectiveness of red-light cameras can be measured in a variety of ways. Common measures include the number or rate of collisions, right-angle crashes, and red-light violations at monitored intersections, as well as measures of crash severity. Studies have also used the number of red-light&ndashrunning citations as a metric.

Costs

Costs will be based on equipment choices, operational and administrative characteristics of the program, and arrangements with contractors. Cameras may be purchased, leased, or installed and maintained by contractors for a negotiated fee ([FHWA and NHTSA, 2008]). In 2001, [35-mm wet-film] red-light cameras cost about $50,000 to $60,000 to purchase and $25,000 to install. Monthly operating costs were about $5,000 [per camera system] ([Maccubbin, Staples, and Salwin, 2001]). (UNC Highway Safety Research Center, 2011, p. 3-13)

A standard digital camera system costs $100,000 for the equipment and installation information on operating costs for the digital system was not reported (Maccubbin, Staples, and Salwin, 2001).

Most jurisdictions contract with private vendors to install and maintain the cameras and use a substantial portion of the income from red-light citations to cover program costs. Speed camera costs probably are similar. (UNC Highway Safety Research Center, 2011, pp. 3-13&ndash3-14)

However, most red-light cameras and speed cameras are separate systems one camera does not enforce both violations.

Time to Implement

Once any necessary legislation is enacted, automated enforcement programs generally require four to six months to plan, publicize, and implement.

Other Issues

Many jurisdictions using automated enforcement are in States with laws authorizing its use. Some States permit automated enforcement without a specific State law. A few States prohibit or restrict some forms of automated enforcement ([GHSA, 2014c] [IIHS, 2014b]). See NCUTLO [National Committee on Uniform Traffic Laws and Ordinances] (2004) for a model automated enforcement law. (UNC Highway Safety Research Center, 2011, p. 3-14)

Public Acceptance

Public surveys typically show strong support for red-light cameras and somewhat weaker support for speed cameras ([IIHS, 2014a] NHTSA, 2004). Support appears highest in jurisdictions that have implemented red-light or speed cameras. However, efforts to institute automated enforcement often are opposed by people who believe that speed or red-light cameras intrude on individual privacy or are an inappropriate extension of law enforcement authority. They also may be opposed if they are viewed as revenue generators rather than methods for improving safety. Per citation payment arrangements to private contractors should be avoided to reduce the appearance of conflicts of interest (FHWA, 2005). (UNC Highway Safety Research Center, 2011, p. 3-14)

Although a recent report by Madsen and Baxandall, 2011, noted that such practices are less common, contracts may still link revenue to citations through a predetermined proportion of revenue a variable proportion of revenues based on timeliness of fine collection, quotas, and volume-based payments and surcharges from fine alternatives, such as traffic school.

Legality

&ldquoState courts have consistently supported the constitutionality of automated enforcement&rdquo (UNC Highway Safety Research Center, 2011, p. 3-14).

Halo Effects

&ldquoMore research is needed to shed light on spillover effects (positive or negative) of automated enforcement programs&rdquo (UNC Highway Safety Research Center, 2011, p. 3-14). In addition, drivers may start to avoid monitored intersections and increase traffic on neighboring streets.


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