Traffic enforcement camera

A red-light camera in use in Beaverton, Oregon, USA

A red-light and speed camera in Darwin, Northern Territory, Australia

A traffic enforcement camera is a system, including a camera and a vehicle-monitoring device, used to detect and identify vehicles disobeying a speed limit or some other road legal requirement. Examples include:

• Speed cameras for identifying vehicles traveling over the legal speed limit. Many such devices use radar to detect a vehicle's speed.
• Red light cameras to detect vehicles which cross a stop-line or designated stopping place after a red traffic light shows.
• Bus lane cameras for identifying vehicles traveling in lanes reserved for buses. In some jurisdictions bus lanes can also be used by taxis and/or vehicles engaged in car pooling.
• Toll-booth cameras for identifying vehicles proceeding through a toll booth without the toll being paid.
• Level crossing cameras for identifying vehicles crossing railways at grade illegally.
• Congestion charge cameras for identifying vehicles for which the charge has not been paid.
• Double solid line cameras for identifying vehicles crossing these lines.
• High-occupancy vehicle lane cameras for identifying vehicles violating the occupancy requirements.[1]
• Turn cameras at intersections where specific turns are prohibited on red. This type of camera is mostly used in cities or heavy populated areas.

There are systems that are combinations of the above; for example, some systems detect both red-light and speed infringements.

History

Gatso speed camera

Dutch company Gatsometer BV, founded by the 1950s rally driver Maurice Gatsonides, invented the first road-rule enforcement cameras. Gatsonides wished to better monitor his speed around the corners of a race track and came up with the device in order to improve his time around the circuit [2]. The company developed the first radar for use with road traffic, and is the world's largest supplier of speed camera systems. Because of this, in some countries all makes of speed cameras are sometimes generically referred to as "Gatsos". They are also sometimes referred to as "photo radar", even though many of them do not use radar.

The first systems introduced in the late 1960s used film cameras to take their pictures. From the late 1990s, digital cameras began to be introduced. Digital cameras can be fitted with a modem or other electronic interface to transfer images to a central processing location automatically, so they have advantages over film cameras in speed of issuing fines, and operational monitoring. However, film-based systems still provide superior image quality in the variety of lighting conditions encountered on roads, do not suffer from pixelation, and are required by courts in some jurisdictions (due to the ease with which digital images may be modified). New film-based systems are still being sold, but digital pictures are providing the greater versatility (although not yet superior image quality) due to ease of data transmission.

Technology

File:Radarfoto.JPG

A picture taken by a speed camera

Vehicle-detection systems used in conjunction with road-rule enforcement cameras include the following:

• Piezo-electric strips - pressure-sensitive strips embedded in the roadway (a set distance apart if speed is to be measured - typically 1-3 metres).
• Doppler radar - a continuous radio signal is directed at a stretch of road, the vehicles and the change in frequency of the returned signal indicates the presence of a moving vehicle and the vehicle's speed.
• Loops - inductive loops embedded in the roadway detect the presence of vehicles, and with two loops a set distance apart vehicle speed can be measured.
• LIDAR - the time of flight of laser pulses is used to make a series of measurements of vehicle position, and from the series of measurements vehicle speed can be calculated.
• Automatic number plate recognition (ANPR) systems that use a form of optical character recognition to read the vehicle's licence or registration plate.

Mobile systems

Gatso Mobile Speed Camera, used in Victoria, Australia. The camera is mounted on the passenger side dash, whilst the black box on the front is the radar unit.

Automatic speed enforcement gantry or "Lombada Eletrônica" with ground sensors at Brasilia, D.F.

Mobile systems can be vehicle-mounted, hand-held, tripod mounted or even concealed in items such as garbage bins. In vehicle-mounted systems, detection equipment and cameras can be mounted to the vehicle itself, or simply tripod mounted inside the vehicle and deployed out a window or door. If the camera is fixed to the vehicle, the enforcement vehicle does not necessarily have to be stationary, and can be moved either with or against the flow of traffic. In the latter case, depending on the direction of travel, the target vehicle's relative speed is either added or subtracted from the enforcement vehicle's own speed to obtain its actual speed. The speedometer of the camera vehicle needs to be accurately calibrated.

Fixed-speed and red light cameras

Most red-light cameras, and many speed cameras, are fixed-site systems mounted in boxes or on poles beside the road. They are also often attached to gantries over the road, or to overpasses or bridges. In some areas such as New South Wales in Australia, there are more pre-configured fixed camera sites than actual cameras, with the camera equipment being rotated periodically between the sites. New digital camera systems in Belgium capture up to 8 lines simultaneously and automatically recognize license plates. They are also linked digitally to a central location to avoid having to recover digital images on-site.

With the introduction of digital technology, it is becoming more common for red-light cameras to also function as fixed speed cameras.

ANPR

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 metres to several hundred kilometres apart) are called automatic number plate recognition (ANPR) cameras. These cameras time vehicles over a known fixed distance, then calculate the vehicle's average speed for the journey. The name derives from the fact that the technology uses infrared cameras linked to a computer to "read" a vehicle's registration number and identify it in real-time.

In principle, it is not possible (as in the case of a single speed camera) to slow down momentarily while passing one of the cameras in order to avoid prosecution, as the average speed over a distance rather than the instantaneous speed at a single point is calculated.

In the case of the Australian SAFE-T-CAM system, ANPR technology is also used to monitor long distance truck drivers to detect avoidance of legally prescribed driver rest periods. The state of Victoria has recently introduced an ANPR system for monitoring passenger vehicles.

In the United Kingdom, automatic number plate recognition (ANPR) average-speed camera systems are known by the Home Office as SVDD (Speed Violation Detection Deterrent). More commonly, they are known by the public by their brand name - SPECS (Speed Enforcement Camera System), a product of Speed Check Services Limited, or just as speed cameras/traps. They are frequently deployed at temporary roadworks sites on motorways, and are increasingly being used at fixed positions across the UK.

Use of ANPR is not limited to traffic-related law enforcement. Under the UK Home Office's "Project Laser", ANPR cameras log all the vehicles passing particular points in the national road network, allowing authorities to track the movement of vehicles and individuals across the country. A similar system is being introduced in Australia.

Manufacturers of traffic enforcement cameras

3M, AlphaTech, Asia Vision, American Traffic Solutions Inc, Computer Recognition Systems Inc, Crown Roadside, Eastman Kodak, Electronic Data Systems, Gatsometer BV, Intertraff, Kria,Laser Technology Inc, Multanova (German site), Parking and Traffic Technologies Ltd, Peek Traffic Solutions, Poltech Internation Limited, Redflex Traffic Systems, RedSpeed International Ltd, SAGEM SECURITE, Sensor Dynamics, Sensys Traffic, Speed Check Services Limited, Tenix Solutions, Traffipax, Inc, Truvelo, Hughes Electronics, UniHz from China, Vitronic GmbH,Topes,

Verification and system testing

In the UK, every speed camera must be calibrated and certified before the images from it are acceptable to the court, including the cameras used in police vehicles. Several speeding prosecutions have failed in the UK due to out of date calibration certificates.

The pictures taken by road-rule enforcement cameras may need to be viewed by a person, and judged to be satisfactory or not, before any infringement notice or ticket is issued. This step is known as verification, and may be a legal requirement in specific jurisdictions. Verifiers typically must check some or all of the following depending on the jurisdiction:

• that there is no sign of interference with the vehicle detector by objects other than the alleged speeding vehicle
• that the licence plate is unambiguously readable according to a legal standard
• that the make and model of vehicle matches that recorded by the licensing authority for the number plate
• that the appearance of the driver in the images is adequate in some way - for example, that it matches the picture on the driving licence of the vehicle's registered owner.

Generally, cameras must undergo approval testing and operational testing to ensure that they function adequately. In the United States, it is common for all installation, operation, and verification procedures to be carried out by private companies that in some states receive payment based on the number of infringements they issue, and often under no testing regime whatsoever.

Issues

Political issues

The use of road rule enforcement cameras is certainly contentious. There are a number of legal issues which arise as a result depending on local laws and the procedures used by the enforcing bodies. There are political issues associated with camera schemes which are often unpopular with motorists and in many areas motorists have lobbied against camera schemes. Finally, there are concerns as to whether road rule enforcement cameras genuinely do improve safety.

In a number of jurisdictions, there was a degree of controversy surrounding the deployment of increasing numbers of speed and red-light cameras beginning in the late 1980s. Police and government were accused of "Big Brother tactics" in over-monitoring of public roads, and of "revenue raising" in applying cameras in deceptive ways to increase government revenue rather than improve road safety.

Often when camera deployment has been accompanied by large scale advertising campaigns explaining the justification and planned effects of such cameras, proponents argue that the public has accepted their use on a large scale. In other places, public responses have included spectacular vandalism of camera systems including attacks with explosives, tractors, cutting equipment, incendiary devices, rifles, and even attacks on camera operators, as forms of violent protest. In the United States, camera enforcement has been controversial since the first speed camera systems issued tickets 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. Four times in the United States, cameras have been rejected after municipal votes. In Peoria, Arizona voters were the first to reject cameras by a 2-1 margin in 1991 followed by a similar vote in Batavia, Illinois in 1992. Anchorage, Alaska rejected cameras in a 1997 referendum and Steubenville, Ohio did so in 2006. In 2002 the state of Hawaii experimented with photo radar vans but they were withdrawn months later due to public outcry. In 2005, the Virginia legislature declined to reauthorize its red light camera enforcement law after a study questioned their effectiveness[3], only to reverse itself in 2007 and allow cameras to return to any city with a population greater than 10,000.

Arkansas, Nebraska, Nevada, New Jersey, Utah, West Virginia and Wisconsin have also enacted various prohibitions on photo enforcement. In New York State, red light cameras are allowed in New York City only, but speeding photo radars are illegal (except in toll lanes equipped with E-ZPass where driving through at a speed in excess of the posted limit can result in a Speed Notice indication). On January 31, 2008, New York State Assemblymember Ivan Lafayette introduced New York State Assembly Bill A09877 with intent to prohibit the sale or use of a product that alerts of the presence of a red light camera under a civil penalty up to 500 USD. The memo of the bill claims New York City's Red-Light Camera Program to be a revenue-neutral success to reduce the running of red lights and improve safety. It was referred to consumer affairs and protection on the same day.

Many North Carolina cities including Charlotte, Greensboro, High Point, and Greenville have also shut down their red-light camera system (even though most are still abandoned in place). This was mostly due to laws governing that 90% of profits from speeding tickets must go to the school systems, thus making the system non-profitable.

Sign notifying drivers of a red light camera in Scarborough, Ontario.

Some U.S. states that formerly allowed only red-light enforcement cameras (but not photo radar speed enforcement cameras), have now approved, or are considering, the implementation of photo radar. The Maryland legislature approved such a program in January 2006. In both 2005 and 2006 the California legislature considered, but did not pass, bills to implement photo radar.[4] Tennessee legislators are also considering expanding[5] their photo radar enforcement after successes in Chattanooga such as generating $158,811 in revenue in the first three months.[6]

In the province of Ontario, Canada, Mike Harris was among the first to make photo radar a substantial election issue. He abolished the program after being chosen as premier in 1995.

In the UK, speed cameras became a contentious political issue after the Department for Transport introduced Safety Camera Partnerships. This lead to the installation of a large number of cameras and enforced that the roughly 15% of the camera revenues that the partnership were able to retain were to be used only for road safety spending (which may or may not include more cameras [7]). This was a departure from the original proposal which was only going to permit spending on cameras and the support infrastructure. The council part of the partnership was not prevented from reducing its road safety budget by a similar amount, effectively channeling the money into its coffers. In 2004, the Conservative Party accused the government of "waging a war on drivers" and announced that, if it came to power, it would review the effectiveness of all cameras in England and Wales, scrapping those which were ineffective.

In July 2005, The Times reported "The Government is blocking the installation of nearly 500 new speed cameras amid signs that ministers are beginning to doubt the effectiveness of the devices." ([8] "Speed camera U-turn as 500 sites rejected", The Times, 15/7/2005) In December 2005 The Times reported "The safety benefits of speed cameras have been exaggerated, the Government admitted yesterday as it called a halt to their proliferation. Cameras do save lives, but far fewer than have been claimed." ([9] "Speed camera benefits overrated", The Times, 16/12/2005)

In February 2006, Edmonton, Alberta, Canada erupted in scandal when it was alleged that two police officers accepted bribes from private contractors who received lucrative contracts to provide photo radar. The officers and contractor involved now face criminal charges that remain before the courts. [10] In October 2006, a similar scandal erupted in St. Peters, Missouri after the mayor pleaded guilty to soliciting payment from a private contractor in return for his approval of an ordinance allowing the use of red light cameras.[11]

Legal issues

Various legal issues arise from such cameras and the laws involved in how cameras can be placed and what evidence is necessary to prosecute a driver varies considerably in different legal systems (U.S. DOT Red Light Camera Systems Operational Guidelines). In some areas the cameras themselves have been ruled illegal. Other issues surround the actual type approval of cameras. For example, with the SPECS cameras (used in the UK to time motorists between two fixed camera sites), it has come to light that the system may be approved for single lane use only. Thus, if a motorist has changed lane between camera sites, then the camera evidence is inadmissible as it falls outside of the system's approval.

One issue is the potential conflict of interest when private contractors are paid a commission based on the number of tickets they are able to issue. Pictures from the San Diego red light camera systems were ruled inadmissible as court evidence in September 2001. The judge said that the "total lack of oversight" and "method of compensation" made evidence from the cameras "so untrustworthy and unreliable that it should not be admitted".

Another common issue is a challenge to the accuracy of the cameras. Cameras which give false positive results can cause legal issues. For example, a speed camera which reports the wrong speed may result in an attempted prosecution of a driver who was not speeding. In particular the cameras have often been accused of photographing the wrong car.

Some legal issues arise from the use of digital images instead of film, with claims that digital images could be created artificially. In August 2005, in Sydney, Australia a speed camera photograph was challenged on the basis that an MD5 hash was insufficient to protect the digital photograph from tampering. Magistrate Lawrence Lawson demanded that the Roads and Traffic Authority produce an expert witness who could prove the photographs were tamper-proof and the RTA was unable to provide such evidence. The defendant was acquitted and awarded court costs.

With regards to red light cameras, in some U.S. jurisdictions (primarily California and Arizona), also in Sweden and Norway, the law says that the camera needs to obtain a photo of the driver's face, of sufficient quality to convince the judge that he is convicting the actual driver, not someone else who had access to the vehicle. Some California cities send registered owners a document that looks like a real camera ticket (but in fact has no legal weight) in an effort to get the owner to identify the driver responsible for the offense.

The UK operates a similar system, where the owners of vehicles photographed on camera are contacted with a 'Notice of Intended Prosecution' (NIP) requiring them to provide the name and address of the driver. Several drivers are challenging this under the Human Rights Act 1998 on the grounds that this amounted to a 'compulsory confession' under the European Convention of Human Rights they could not be required to give evidence against themselves, that the police in obtaining this confession are not acting in accordance with the Police and Criminal Evidence Act 1984 (PACE) and that since the camera partnerships that include the police, local authorities, Magistrates Courts Service (MCS) and Crown Prosecution Service (CPS) are not independent, having a joint financial interest in the fine revenue and therefore defendants do not get a fair trial. Although their plea was initially granted by a judge, it was later overturned, and was considered serious enough breach of human rights by the human rights campaign group Liberty that this matter is to be heard in the European Court of Human Rights (ECtHR), and the European Court of Justice (ECJ). Also there are questions as to whether or not government is contravening their citizen's rights under the Bill of Rights 1689 and the Magna Carta the founding principles of UK's democratic constitution. Some states of Australia have a similar system where the owner must report the driver or pay himself.

Other U.S. states and provinces of Canada such as Alberta are "owner liability" jurisdictions where the issue of driver identification is avoided by not issuing demerit points for camera infractions. Instead, the registered owner of the vehicle must pay all such fines regardless of whether he was driving at the time of the offense. Most U.S. jurisdictions release the owner from liability if he signs a form identifying the actual driver and that individual pays the fine. However, the resulting lack of long-term repercussions for repeated photo radar offenses has been criticized by some as giving a "license to speed" to those who can more easily afford speeding fines.

In Albuquerque, New Mexico, the city government attempted to bypass the legal issue of a defendant's right to cross-examine his accuser, as well as the issue of verifying the driver's identity. Automated red-light and speeding offenses are classed as public nuisances and fined to the vehicle's registered owner as civil violations, not as criminal offenses.

In the U.S. state of Ohio, the issue of whether a city has jurisdiction under the Ohio Constitution to issue citations based on speed cameras will be heard by the Ohio Supreme Court on September 18, 2007, in the case of Kelly Mendenhall et al. v. The City of Akron et al.[12][13]

Issues of effectiveness

UK-based studies

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In the UK, the effectiveness issue became particularly contentious upon the introduction of Safety Camera Partnerships. Studies in the UK have provided analysis of the effects of speed cameras deployed by Safety Camera Partnerships. This led to a change in the arrangements for the revenue raised by the partnerships in 2007; funding is no longer kept by them, it is retained by central government.

An initial three-year study commissioned by the Department for Transport (DfT) [14] showed that vehicle speeds dropped by seven percent at sites where cameras were installed and claimed that "at camera sites, there was also a reduction of over 100 fatalities per annum (40% fewer). There were 870 fewer people killed or seriously injured and 4,030 fewer personal injury collisions per annum. There was a clear correlation between reductions in speed and reductions in PICs" (personal injury collisions). The three year DfT report was criticised in some quarters for giving only a small amount of attention to the phenomenon of regression to the mean (RTM). Since the cameras were placed at sites where a high number of accidents had been observed, a lower number of accidents might be expected in subsequent years simply by random chance. Professor Mervyn Stone of The Department of Statistical Science at University College London was commissioned by the BBC Radio Four Today Programme to write a report about UK speed cameras and also Traffic Calming. His report criticises some of the methodologies used in some speed camera studies (including the DfT three year report) and in particular he mentions the RTM effect.

A follow-up four-year independent study commissioned by the DfT [15] concluded "after allowing for the long-term trend, but without allowing for selection effects (such as regression-to-mean) there was a 22% reduction in personal injury collisions (PICs) at sites after cameras were introduced. Overall 42% fewer people were killed or seriously injured. At camera sites, there was also a reduction of over 100 fatalities per annum (32% fewer). There were 1,745 fewer people killed or seriously injured and 4,230 fewer personal injury collisions per annum in 2004." In addition, the four year report includes statistical modeling of the RTM effect based on a reduced set of camera sites for which suitable data was available (see [16] appendix H --- tables H3 and H7). Rural roads were excluded from the RTM modeling, because of difficulties establishing representative models for such roads, although the report does state it is likely that RTM effects will be larger for rural roads because expected collision frequencies tend to be lower than on urban roads. The report urges caution in drawing too strong conclusions from a small data set. Based on the RTM modeling undertaken the report suggests that for personal injury collisions (non-serious collisions resulting in injuries) a 16.2% reduction in injuries was due to the cameras, a 6.7% reduction was due to regression to the mean and a 7.9% reduction was due to the general downward trend in accidents over the period. For fatal and serious collisions, the modeling estimated a 10.4% reduction in such collisions due to the cameras, a 34.8% reduction due to regression to the mean and a 9.3% reduction due to general downward trends in accident rates.

A 2006 DfT report "Contributory factors to road accidents" uses STATS19 data to analyse accidents have speed as a contributory factor. The factors "exceeding the speed limit" or "going too fast for conditions" were judged by officers at the scene of road accidents. It was suggested that "exceeding the speed limit" would be marked as a cause if the officer had reason to believe from external evidence (for example "skid marks on the road") that the driver was doing so. Exceeding the speed limit was said to be a factor in 12% of fatal road accidents and 5% of all road accidents.

An independent UK-based controlled study uses STATS19 data to show that speed cameras are effective at reducing accidents and injuries but added that wider deployment would improve their effectiveness.

Two 2006 UK studies have questioned the accuracy of STATS19 data when used to look at serious injury rates since there is ambiguity in whether an injury is judged serious or minor and the UK police records do not match hospital admission records. The first study "Changes in safety on England’s roads: analysis of hospital statistics", published by the British Medical Journal concludes that "the overall fall seen in police statistics for non-fatal road traffic injuries probably represents a fall in completeness of reporting of these injuries". The second study "Under-reporting of Road Casualties – Phase 1", published by the DfT, recommends that reports should not rely solely on STATS19 injury data (none of the reports mentioned do).

In 2003, Northumbria Police's Acting Chief Inspector of motor patrols is reported to have said "Speed cameras don't reduce casualties - they are just for revenue generation", he also said "They don't engage and they aren't going to send you a message in the post telling you were driving badly". However he went on to say that "Speed cameras achieve speed reduction at accident blackspots and free up officers to concentrate on education and advice".

US-based studies

Red light camera in Springfield, Ohio, USA.

In the United States, questions of effectiveness have centered on the more common red light cameras. A number of government-sponsored studies have addressed the question of whether, on balance, the devices produce a safety benefit. A U.S. Safety Evaluation of Red-Light Cameras, for example, found that red light cameras led to a decrease in right-angle crashes and an increase in the number of rear-end collisions. The total number of collisions remained essentially unchanged. The study applied estimates from a 1997 study of the cost of accidents based on severity to conclude the cameras yielded a positive overall cost benefit from a reduction in more expensive right-angle injury collisions.

A 2005 Virginia Department of Transportation study of the long-term effect of camera enforcement in the state found a decrease in the number of right-angle crashes, but an increase in rear-end crashes and an overall increase in the number of accidents causing injuries. The report recommended further study of the issue to determine whether the severity of the eliminated red light running crashes was greater than that of the induced rear-end crashes. The department released a more extensive evaluation of the data in 2007 which showed that the overall number of accidents at intersections with red light cameras increased in four of the five cities using the technology. Fairfax City reported a 7% drop in the overall number of accidents and a 5% drop in injury accidents while overall the state's cameras were correlated with a 29% increase in overall accidents and an 18% increase in injury accidents. (Study text in PDF). This study also notably found that red-light violations decreased by 94% at one Fairfax County intersection, after the advent of a 1.5 second longer yellow-light cycle.

A 2004 Texas Transportation Institute study found, "crashes decrease with an increase in yellow interval duration and a reduction in speed limit." After 1.0 second was added to the yellow signal timing at test intersections, accidents dropped by 35 to 40%. This compares with a 6.4% reduction for "area-wide officer enforcement of intersection traffic control devices... during the time of the enforcement activity" (Study text in PDF).

A 2005 study of the Raleigh, North Carolina red light camera program conducted by the Institute for Transportation Research and Education at North Carolina State University compared “before” and “after” red-light camera intersection data and found right-angle crashes dropped by 42 percent, rear-end crashes dropped by 25 percent and total accidents dropped by 22 percent. ([17])

A 2007 study of speed cameras on the Arizona State Route 101 in Scottsdale found a 50% reduction in the total crash frequency, with injuries falling by 40%. However rear-end collisions increased by 55%.

Australia based studies

In the state of Victoria, Australia, widespread and increased use of speed cameras has given rise to public criticism over whether the collection of over $400 million in speed camera revenue during the 2003-04 financial year raises questions of fairness and equity. With drivers being fined for speeding at only a few km/h above the speed limit and receiving the infringement notice up to months later, many have questioned whether there may be education and enforcement measures available that place less of an imposition on motorists.

Counter technology

A GPS map showing speed camera POI information overlaid onto it

Methods used to avoid detection by cameras include:

• Braking just before a camera in order to travel past it below the speed limit. (This method may not work for average speed cameras though, that use the time taken to cover a known distance between two points to calculate average speed, as opposed to measuring a vehicle's speed at only a single point). The driver needs to know the location of a camera in order to react in time. Methods that drivers use to locate cameras include:
  • Sighting the camera, camera operator(s) or their vehicle.
  • Memory.
  • Word of mouth or public broadcast (for example from a radio station).
  • Publicly available information, including websites listing camera locations.
  • Warnings from other motorists (for example via CB radio, hand signals or flashing headlights)
  • Seeing the reactions of other motorists ahead of them (e.g. braking)
  • Devices such as passive laser detectors and radar detectors, which detect when the vehicle's speed is being monitored and warn the driver (these may be illegal in some areas).
  • Devices such as laser jammers and radar jammers, which actively "jam" the laser and radar by returning a scrambled signal which the speeding camera cannot process (these may be illegal in some areas).
  • Devices which use a Global Positioning System and a database of known camera locations (Points of Interest) to warn the driver when a camera is nearby. This method relies on an up-to-date database of camera positions. One such database is supplied by PocketGpsWorld.com and covers multiple countries worldwide. (PNAs with this functionality are also illegal in some areas, e. g. Germany.)

• Removing, falsifying or obscuring the vehicle license plate. It is often illegal if the plate cannot be read by other people or by a camera. Treatments which claim to obscure the plates from cameras, but leave them visible to other drivers are typically considered to be of dubious efficacy. Such treatments include the use of anti-flash spray that adds a high-gloss finish to the plate (causing the camera's flash to over-expose the picture making the plate unreadable), or an infrared filter (that renders the number unreadable when illuminated by the infrared flashlights of certain speed cameras).
• Drivers obscuring their faces to avoid being identified. As summonses from certain cameras require drivers' faces in addition to vehicular license plates, drivers whose faces are obscured (including motorcyclists wearing full-face helmets) have avoided the issuance of certain summonses.
• In the case of photographic cameras that operate by measuring the short distance travelled by a vehicle in the brief interval between two timed photographs, there are theories that a "maximum speed" exists. Thus, a vehicle travelling at or above this speed will have passed through the camera's field of view before the second photograph is taken, rendering measurement impossible. Estimates vary, but a figure of 170mph (274km/h) is commonly cited. In 2005 the BBC television programme Top Gear tested this theory, with inconclusive results. This theory is also commonly extended to radar and lidar devices, but its effectiveness is questionable.

On the American television program MythBusters episode Speed Cameras, the hosts use various methods to attempt to trick or diminish the effectiveness of traffic enforcement cameras with mixed results.

See also

• Road safety
• Road traffic control
• Safe Speed
• Speed trap
• Speed cameras in Australia
• Safety Camera Partnership
• Fourth Amendment to the United States Constitution-which has been used to limit use of speed cameras in the USA.

External links

Articles on enforcement cameras

• Red Alert: Everything they really don't want you to know about those pesky traffic-light cameras Riverfront Times
• Dallas' red light cameras may face changes as revenue estimate drops By Dave Levinthal, The Dallas Morning News

Enforcement cameras

• PhotoEnforced.com Crowd Sourced Database Speed and Red Light Camera Locations
• Photo Enforcement Gallery at roadtraffic-technology.com
• UK Home Office approved speed detection devices - March 2007

Example images from cameras

• UK pics
• [18]United Kingdom speed camera maps

For enforcement cameras

• National Safety Camera initiative (UK)
• National Campaign to Stop Red Light Running (U.S.)
• Advocates for Highway and Auto Safety (U.S.)
• FHWA (U.S.)
• Insurance Institute for Highway Safety (U.S.)
• Governors Highway Safety Association (U.S.)
• American Association of State Highway and Transportation Officials (AASHTO) (U.S.)
• Speed Cameras: 10 criticisms and why they are flawed (PDF) A joint release from PACTS and The Slower Speeds Initiative

Against enforcement cameras

• SENSE - (British Columbia)
• National Motorists Association (U.S.) info
• Rethinking red-light cameras by Bob Barr, former U.S. Congressman (U.S.)
• Info about fake tickets in California (U.S.)

Speed camera discussion forum

• Discussion about commercially available speed camera alerts (Covers 40 countries)