The concept of the speed camera can be dated back to at least 1905; Popular Mechanics reports on a patent for a Time Recording Camera for Trapping Motorists which enabled the operator to take time-stamped images of a vehicle moving across the start and end points of a measured section of road. The timestamps enabled the speed to be calculated, and the photo enabled identification of the driver.

Photo Defense -online listing of Photo Radars

Photo Radars listed by State:

Alabama Alaska Arizona Arkansas California Canada Colorado Connecticut DC Delaware Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisianna Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Outside USA Pennsylvania Photo Defense Photo Radar News Photo Radar Resources Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming There are 89 links for you to choose from!

The Dutch company Gatsometer BV, founded by the 1950s rally driver Maurice Gatsonides, invented the first automated 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. 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 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 the greater versatility and are now significantly more popular.

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 measure a vehicle's instantaneous speed.
  • Sets of multiple cameras with number-plate recognition software which can check the average speed of a vehicle between two points.
• 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 paying the toll.
• Level crossing cameras for identifying vehicles crossing railways at grade illegally.
• Congestion charge cameras for recording vehicles inside the chargeable area.
• Double solid line cameras for identifying vehicles crossing these lines.
• High-occupancy vehicle lane cameras for identifying vehicles violating the occupancy requirements.
• Turn cameras at intersections where specific turns are prohibited on red. This type of camera is mostly used in cities or heavy populated areas.
• Parking Cameras which issue citations to vehicles which are illegally parked or which were not moved from a street at posted times

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

Existing traffic cameras, as well as special purpose ANPR cameras, can also be used for non-traffic-enforcement related activities, notably for mass surveillance of motorists by government agencies.