Speed cameras

A traffic enforcement camera (also red light camera, road safety camera, road rule camera, photo radar, photo enforcement, speed camera, Gatso) is an automated ticketing machine. It may include a camera which may be mounted beside or over a road or installed in an enforcement vehicle to detect traffic regulation violations, including speeding, vehicles going through a red traffic light, unauthorized use of a bus lane, for recording vehicles inside a congestion charge area.
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. Vehicles 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 the Human Rights Act 1998 was not being breached. Some groups, such as the National Motorists Association in the USA, claim that systems "encourage ... revenue-driven enforcement" rather than the declared objectives.

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 registation 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.

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.

Speed limit enforcement

Speed enforcement cameras are used to monitor compliance with speed limits which may use Doppler, LIDAR 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 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.

Stop sign enforcement

In 2007, the Mountains Recreation and Conservation Authority (MRCA), in California, installed the first stop sign cameras in the United States. The five cameras are located in state parks such as Franklin Canyon Park and Temescal Gateway Park. The operator, Redflex Traffic Systems Inc., is paid $20 per ticket. The fine listed on the citation is $100. In 2010 a class action law suit was filed against MRCA.

Number plate recognition systems
Main article: Automatic number plate recognition
Automatic number plate recognition can be used for purposes unrelated to enforcement of traffic rules. In principle any agency or person with access to data either from traffic cameras or cameras installed for other purposes can track the movement of vehicles for any purpose.
In Australia's SAFE-T-CAM system, ANPR technology is used to monitor long distance truck drivers to detect avoidance of legally prescribed driver rest periods.
The United Kingdom's police ANPR system logs all the vehicles passing particular points in the national road network, allowing authorities to track the movement of vehicles and individuals across the country.
In the UK an 80-year-old pensioner John Catt and his daughter Linda (with no criminal record between them) were stopped by City of London Police while driving in London, UK in 2005, had their vehicle searched under section 44 of the Terrorism Act 2000 and were threatened with arrest if they refused to answer questions. After they complained formally, it was discovered they were stopped when their car was picked up by roadside ANPR CCTV cameras; it had been flagged in the Police National Computer database when they were seen near EDO MBM demonstrations in Brighton. Critics point out that the Catts had been suspected of no crime, however the UK's mass surveillance infrastructure allowed them to be targeted due to their association.

Other
Congestion charge cameras to detect vehicles inside the chargeable area which have not paid the appropriate fee
High-occupancy vehicle lane cameras to identify vehicles violating occupancy requirements.
Level crossing cameras to identifying vehicles crossing railways at grade
Noise pollution cameras that record evidence of heavy vehicles that break noise regulations by using engine braking
Parking cameras which issue citations to vehicles which are illegally parked or which were not moved from a street at posted times.
Toll-booth cameras to identify vehicles proceeding through a toll booth without paying the toll
Turn cameras at intersections where specific turns are prohibited on red. This type of camera is mostly used in cities or heavy populated areas.
Automatic number plate recognition systems can be used for multiple purposes, including identifying untaxed and uninsured vehicles, stolen cars and potentially mass surveillance of motorists .
Fixed camera systems can mounted in boxes or on poles beside the road or attached to gantries over the road, or to overpasses or bridges. Cameras can be concealed, for example in garbage bins.
Mobile speed cameras may be hand-held, tripod mounted, or vehicle-mounted. 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.
Some number plate recognition systems can be used from vehicles.