<P> A red light camera (short for red light running camera) is a type of traffic enforcement camera that captures an image of a vehicle which has entered an intersection in spite of the traffic signal indicating red (during the red phase). By automatically photographing vehicles that run red lights, the photo is evidence that assists authorities in their enforcement of traffic laws . Generally the camera is triggered when a vehicle enters the intersection (passes the stop - bar) after the traffic signal has turned red . Typically, a law enforcement official will review the photographic evidence and determine whether a violation occurred . A citation is then usually mailed to the owner of the vehicle found to be in violation of the law . These cameras are used worldwide, in countries including: Australia, New Zealand, Canada, the United Kingdom, Singapore and the United States . If a proper identification cannot be made, instead of a ticket, some police departments send out a notice of violation to the owner of the vehicle, requesting identifying information so that a ticket may be issued later . </P> <P> There is debate and ongoing research about the use of red light cameras . Authorities cite public safety as the primary reason that the cameras are installed, while opponents contend their use is more for financial gain . There have been concerns that red light cameras scare drivers (who want to avoid a ticket) into more sudden stops, which may increase the risk of rear - end collisions . The elevated incentive to stop may mitigate side collisions . Some traffic signals have an all red duration, allowing a grace period of a few seconds before the cross-direction turns green . Some studies have confirmed more rear - end collisions where red light cameras have been used, while side collisions decreased, but the overall collision rate has been mixed . In some areas, the length of the yellow phase has been increased to provide a longer warning to accompany the red - light - running - camera . There is also concern that the international standard formula used for setting the length of the yellow phase ignores the laws of physics, which may cause drivers to inadvertently run the red phase . </P>

When is it considered running a red light