Traffic Radar and Other Techniques Used to Monitor Driving

Today, law enforcement has more than a few means of surveillance and radar when it comes to curbing traffic violations. Although we all know to watch for police cars parked off the highway while rushing to get home, getting directly caught by a police officer’s own two eyes aren’t the only way of earning a traffic citation anymore. Traffic radar to gauge speeds of approaching vehicles and radar trailers to display speeds of passing vehicles now make speeding tickets much easier to give, and red light and traffic surveillance cameras ensure that we are adhering to the rules of the road even when an officer isn’t directly present at the scene. That is why it’s important to understand how these various techniques work that officers use to gauge our conduct behind the wheel.

When most of us think of radar, images of satellites, antennas, and large radio towers dominate. However, all of the sophisticated radar is unnecessary to simply monitor the speed of approaching or passing cars. When an officer is parked on the side of the interstate tracking everyone’s speed, what he is doing is simply using a handheld device that sends microwaves toward oncoming cars. Microwaves reflect off of shiny, metallic surfaces. When they hit oncoming vehicles coming down the highway, they reflect off the surface of the car in many different directions. These scattered signals can be easily picked up by a radio receiver which can measure the speed of the car by measuring how the microwaves were reflected, and all in less than half a second. The officer then reads this number and subjectively decides if the speed the car is travelling warrants a citation. Radar trailers work in the same way, but they are the big speed signs that display how fast you’re going for you and all the world to see, including any cops who may be watching.

“Red light camera” is short for “red light running camera” because they catch drivers running red lights (the field of law enforcement is not known for creatively naming technology). These cameras actually consist of three parts: cameras, triggers, and a computer to process the input. When a stoplight turns red, the camera is essentially primed, and any vehicle that proceeds through the intersection after the light has turned triggers the camera, which often takes pictures of the driver, car, and license plate. The information is the processed and a citation is issued to the driver. In some cities that have these red light cameras in place, the citations are first reviewed by an officer before they are sent out because the cameras function without human judgment and sometimes issue a citation that a human police officer would understand as unwarranted.

Although many of these technologies seem like a nuisance to the driver running late for work, they in fact contribute substantially to the safety of the road. Highways known for frequent police surveillance often see few speeding vehicles since drivers know the odds of getting pulled over are higher, which then leads to fewer automobile accidents. The red light cameras and traffic cameras also discourage reckless driving through intersections where they are known to be installed, and there are almost never any repeat offenders at the same intersection. Cumulatively, radar and surveillance tools used by law and traffic enforcement save millions of dollars in vehicle collisions and passenger casualties, as well as generate revenue for city while simultaneously discouraging reckless drivers.