Speed cameras are located on posts near the sides of roads that law enforcement agencies have identified as important for monitoring, notes Siouxland News. They are positioned to serve as a deterrent by their very presence, as well as to document violations in all lanes of traffic.
Also called photo-radar, speed cameras trigger when a vehicle travels by at a speed that is a set amount over the existing speed limit. The cameras provide a date-and-time stamp with the picture, as well as the speed that the vehicle was traveling when it attracted the attention of the camera, notes PhotoEnforced.com.
In some jurisdictions, law enforcement authorities post warning signs ahead of the cameras to give motorists a chance to reduce their speed before having their violation documented. In some areas, many of the cameras are left inactive, serving by their mere presence as a deterrent against speeding. In England and Wales, less than half of the posted speed cameras are turned on at any given time, as noted by the Daily Mail in 2011.
With active cameras, law enforcement staff download violation images at preset intervals, and owners of photographed cars receive citations, according to Siouxland News. The fee for each violation varies with the city, county or entity posting the cameras.