How bright are red light cameras?

Just as a quick explanation - As a vehicle approaches an intersection the vehicle is detected with a series of in-ground loop detectors. Based on time distance calculations the speed of the vehicle is determined. The computer takes inti account the speed of a vehicle and the likelihood that the vehicle will violate the red light based on the traffic signal phasing. If the computer determines that a violation is likely then the cameras will be activated.

Another View: -OR- it operates as simply as the camera being turned on whenever the red light is lit. Then, it takes a picture of any vehicle crossing the intersection AFTER the red light has actually illumminated.