Red light cameras have been recently introduced to our streets and touted as a way to keep traffic violations under control without spending a lot of money of police officers. As they’ve appeared, however, many people are viewing them with suspicion. They have been blamed for everything from decreasing privacy to making up violations in order to gain more revenue for the cities they’re installed in. Understanding how these cameras work might help to alleviate some of these fears.
Essentially, red light cameras work by taking a picture of any car that goes through an intersection while the light for their lane is red. To do this, cameras are mounted above the traffic lights themselves. In some areas, they are installed on top of telephone poles or other structures near the intersection.
Depending on the type of camera that is installed, the camera takes pictures using one of two methods. The earliest cameras were wired to motion sensors on street level. These sensors were turned off and on by being programmed with the schedule of the streetlights. When the streetlight was red, the camera turned on, when it was green, it turned off. When the motion of a car was recorded by the sensors, it sent a message to the camera to take a picture.
There were several problems with these cameras. To start, the motion sensors were known for getting out of synch with the stop lights, making them snap pictures of the first car through an intersection and wrongly sending that driver a ticket. Secondly, the motion sensors were often triggered by legal crossings, such as ambulances and in some cases people with baby strollers. This made these cameras easy to challenge in court, and many cities soon got rid of theirs.
The next type of red light camera uses both a motion sensor and a light sensor attached to the stoplight. The light sensor detects when the light is red, and immediately tells the motion sensor to turn on. Any motion through the intersection is recorded on the camera. These images are then processed by software that deletes images of ambulances, birds, and other non-car motion.
The software then transmits a batch of images that consist of the back of vehicles going through an intersection with a red light. The license plates on these vehicles are then run through a database and the pictures along with a ticket are mailed to the driver’s home.
If you live in a city with red light cameras, there are several things you can do to avoid them. Obviously, make sure you slow down at yellow lights so that you don’t get caught going through an intersection as the light turns. If you have a habit of doing this, however, you might want to try braking as soon as you see a yellow light. If you get in the habit, it will get a lot of easier.
There are a lot of products on the market designed to obscure your license plate so that these cameras cannot read it. Depending on where you live, these products might be illegal, so be careful when using them.