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Traffic enforcement camera

Traffic enforcement camera is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Traffic enforcement camera rather than just read about it. In short: A traffic enforcement camera (also a red light camera, speed camera, road safety camera, bus lane camera, depending on use) is a camera which may be mounted beside or over a road or installed in an enforcement vehicle to detect motoring offenses, including speeding, vehicles going through a red traffic light, vehicles going through a toll booth without paying, unauthorized use of a bus lane, or for recording vehicle…

Traffic enforcement camera — main illustration
Traffic enforcement camera — illustration

Key takeaways

  • Traffic enforcement camera belongs to physics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Traffic enforcement camera to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Traffic enforcement camera from memory before moving on to harder problems.

Reference excerpt

A traffic enforcement camera (also a red light camera, speed camera, road safety camera, bus lane camera, depending on use) is a camera which may be mounted beside or over a road or installed in an enforcement vehicle to detect motoring offenses, including speeding, vehicles going through a red traffic light, vehicles going through a toll booth without paying, unauthorized use of a bus lane, or for recording vehicles inside a congestion charge area. It may be linked to an automated ticketing system. A worldwide review of studies found that speed cameras led to a reduction of "11% to 44% for fatal and serious injury crashes". The UK's Department for Transport estimated that cameras had led to a 22% reduction in personal injury collisions and 42% fewer people being killed or seriously injured at camera sites. The British Medical Journal reported that speed cameras were effective at reducing accidents and injuries in their vicinity and recommended wider deployment. An LSE study in 2017 found that "adding another 1,000 cameras to British roads could save up to 190 lives annually, reduce up to 1,130 collisions and mitigate 330 serious injuries." Research indicates that automated traffic enforcement alleviates biases associated with police stops. The latest automatic number-plate recognition systems can be used for the detection of average speeds and raise concerns over loss of privacy and the potential for governments to establish mass surveillance of vehicle movements and therefore by association also the movement of the vehicle's owner. Vehicle owners are often required by law to identify the driver of the vehicle and a case was taken to the European Court of Human Rights which found that human rights were not being breached. Some groups, such as the American Civil Liberties Union in the US, claim that "the common use of speed traps as a revenue source also undercuts the legitimacy of safety efforts."

History

The idea of the speed cameras dates back to the late 19th century: the 1894 science fiction novel A Journey in Other Worlds, set in the year 2000, includes a description of "instantaneous kodaks" used by police to enforce speed limits. In 1905, Popular Mechanics reported on a patent for a "Time Recording Camera for Trapping Motorists" that enabled the operator to take time-stamped images of a vehicle moving across the start and endpoints of a measured section of road. The timestamps enabled the speed to be calculated, and the photo enabled identification of the driver. The Dutch company Gatsometer BV, which was founded in 1958 by rally driver Maurice Gatsonides, produced the 'Gatsometer'. Gatsonides wished to better monitor his average speed on a race track and invented the device in order to improve his lap times. The company later started supplying these devices as police speed enforcement tools. The first systems introduced in the late 1960s used film cameras to take their pictures. Gatsometer introduced the first red light camera in 1965, the first radar for use with road traffic in 1971 and the first mobile speed traffic camera in 1982; From the late 1990s, digital cameras began to be introduced. Digital cameras can be fitted with a network connection to transfer images to a central processing location automatically, so they have advantages over film cameras in speed of issuing fines, maintenance and operational monitoring. However, film-based systems may provide superior image quality in the variety of lighting conditions encountered on roads, and are required by courts in some jurisdictions. New film-based systems are still being sold, but digital pictures are providing greater versatility and lower maintenance and are now more popular with law enforcement agencies. The first speed camera systems in the US were in Friendswood, Texas, in 1986 and La Marque, Texas, in 1987. Neither program lasted more than a few months before public pressure forced them to be dropped.

Types

Bus lane enforcement Some bus lane enforcement cameras use a sensor in the road, which triggers a number-plate recognition camera, which compares the vehicle registration plate with a list of approved vehicles and records images of other vehicles. Other systems use a camera mounted on the bus, for example in London where they monitor Red routes on which stopping is not allowed for any purpose (other than taxis and disabled parking permit holders). On Monday, February 23, 2009, New York City announced testing camera enforcement of bus lanes on 34th Street in Midtown Manhattan where a New York City taxi illegally using the bus lanes would face a fine of $150 adjudicated by the New York City Taxi and Limousine Commission. In October 2013, in Melbourne (Australia), Melbourne Airport introduced seven automatic number-plate recognition (ANPR) cameras in their bus forecourt to monitor bus lanes and provide charging points based on vehicle type and the dwell time of each vehicle. Entry and exit cameras determine the length of stay and provide alerts for unregistered or vehicles of concern via onscreen, email, or SMS-based alerts. This system was the first of several Sensor Dynamics based ANPR solutions.

Red light enforcement

A red light camera is a traffic camera that takes an image of a vehicle that goes through an intersection where the light is red. The system continuously monitors the traffic signal and the camera is triggered by any vehicle entering the intersection above a preset minimum speed and following a specified time after the signal has turned red. Red light cameras are also utilized in capturing texting-while-driving violators. In many municipalities, an officer monitors the cameras in a live command center and records all violations, including texting at a red light.

Speed limit enforcement

Speed enforcement cameras are used to monitor compliance with speed limits, which may use Doppler radar, LIDAR, stereo vision or automatic number-plate recognition. Other speed enforcement systems are also used which are not camera based. Fixed or mobile speed camera systems that measure the time taken by a vehicle to travel between two or more fairly distant sites (from several hundred meters to several hundred kilometers apart) are called average speed cameras. These cameras time vehicles over a known fixed distance, and then calculate the vehicle's average speed for the journey.

Stop sign enforcement

… excerpt ends here. Continue reading the full article.

Illustrations

Traffic enforcement camera: A Gatso speed camera. The camera's lens is visible at top left, while the large flash, used for illuminating number plates and calibration lines on the road when taking photographs, is visible on the bottom right.
A Gatso speed camera. The camera's lens is visible at top left, while the large flash, used for illuminating number plates and calibration lines on the road when taking photographs, is visible on the bottom right.
Traffic enforcement camera: A speed camera in Mong Kok, Hong Kong
A speed camera in Mong Kok, Hong Kong
Traffic enforcement camera: A speed camera on the Highway 5 in Joroinen, South Savo, Finland
A speed camera on the Highway 5 in Joroinen, South Savo, Finland
Traffic enforcement camera: Older traffic enforcement camera in Ludwigsburg, Germany
Older traffic enforcement camera in Ludwigsburg, Germany
Traffic enforcement camera: Automatic speed enforcement gantry or "Lombada Eletrônica" with ground sensors in Brasília, D.F
Automatic speed enforcement gantry or "Lombada Eletrônica" with ground sensors in Brasília, D.F

Worked examples

Example 1 — a first encounter with Traffic enforcement camera

Start with the simplest possible case. Write down what Traffic enforcement camera claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Traffic enforcement camera before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Traffic enforcement camera ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Traffic enforcement camera

In research
Traffic enforcement camera appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Traffic enforcement camera in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Traffic enforcement camera is common in secondary-school and first-year university syllabi. It links to neighbouring topics Applications of computer vision, Cameras by type, Dutch inventions, so understanding it makes those chapters shorter.
In everyday life
Look for Traffic enforcement camera outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Traffic enforcement camera in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Traffic enforcement camera means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Traffic enforcement camera out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Traffic enforcement camera in simple terms?

A traffic enforcement camera (also a red light camera, speed camera, road safety camera, bus lane camera, depending on use) is a camera which may be mounted beside or over a road or installed in an enforcement vehicle to detect motoring offenses, including speeding, vehicles going through a red tra…

Why does Traffic enforcement camera matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Traffic enforcement camera?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Traffic enforcement camera.

Tags

  • Applications of computer vision
  • Cameras by type
  • Dutch inventions
  • Law enforcement equipment
  • Road traffic management
  • Street furniture
  • Traffic enforcement cameras
  • Traffic law
  • Transportation engineering

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