A traffic camera is a video camera which observes vehicular traffic on a road. Typically, these are put along major roads such as highways, freeways, motorways, autoroutes and expressways, as well as arterial roads, and are connected with optical fibers buried alongside or even under the road, with electrical power either provided by mains power in urban areas, or via solar panels or another alternate power source which provides consistent imagery without the threat of a power outage during inclement conditions.
A monitoring center receives the live video in real time, and serves as a dispatcher if there is a traffic collision or some other disruptive incident or road safety issue.
Traffic cameras are a major part of most intelligent transportation systems. They are especially valuable in tunnels, where safety equipment can be activated remotely based upon information provided by the cameras and other sensors. On surface roads, they are typically mounted on high poles or masts, sometimes along with street lights. On arterial roads, they are often mounted on traffic light poles at intersections, where problems are most likely to occur. In remote areas without easy reach of the main electrical grid, they are usually powered by another means such as solar power, which also provides a backup source to urban camera infrastructure.
Traffic cameras are distinct from road safety cameras, which are put in specific places to enforce rules of the road. Those cameras take still photos in a much higher image resolutionupon a trigger, whereas traffic cameras are simply for observation and constantly take lower-resolution video, often in full motion, though they are remotely controllable in order to focus on an ongoing traffic incident farther along a road that may not be in the camera’s usual field of view or even along a frontage road or other roadway within its field of vision. Many transmit in the legacy analog NTSC and PAL formats, depending on location, though many are being converted to high definition video as equipment is replaced. Some have a compass built in which displays the cardinal direction at which the camera is aimed, though many providers also provide a reference image of a shot with the cardinal direction.