How does photo radar work? Photo radar is made up of the following:

● a high speed traffic camera and flash unit

● a narrow beam, low-powered Doppler radar antenna aimed across the road

● a computer that records information, such as date, time, speed, and location of the violation

Photo radar works this way. First, the system is hoisted onto a police vehicle that typically patrols areas where overspeeding is a problem. Then, it catches speed demons and those who run against red lights. Drivers can see their vehicles' speed from a reader board found in the back window of the police unit display.

Many disgruntled drivers have successfully parlayed their dislike for photo radars into a lucrative business. They produce products that supposedly protect drivers from being photographed by photo radars. Below are some of the products and a brief description of how they are used.

● Radar Detectors

A radar detector detects the presence of photo enforcement devices. Accordingly, it assists drivers in beating photo radars by warning them of photo radar presence. This gives drivers time to slow down. Many claim radar detectors are effective. One problem with radar detectors, however, is that these do not work with red light cameras that measure speed using sensors embedded in roadways.

● Flash-back device

What senses the flash of a photo enforcement camera and immediately flashes its own strobe light onto the license plate to make license numbers invisible to cameras? Why, a flash-back device, of course! Flash-back devices are highly popular, especially because they're cheap. A study, shows however, that flash-back devices are ineffective in beating photo radars when Redflex sensor-based photo enforcement cameras are used.

● GPS-based warning systems

Radar detectors are illegal, and in some states, use of flash-back devices are implicitly prohibited. What do drivers interested in beating photo radars without breaking the law do? They buy GPS-based warning systems. These devices, which are very popular in European markets, has just recently become available in the United States.

This is how a GPS-based warning system works: you download the location of speed enforcement cameras into a GPS system. Because your system now has a map of camera locations, it warns you to slow down every time you are close to a photo radar.

While a GPS-based technology may seem infallible, it is not without its faults. To be effective, it relies on your knowledge of photo radars' locations. This is knowledge you may not always have. All it takes for you to get a citation is one speed camera unregistered in your GPS system.

● Plate covers

Plate covers are cheaper alternatives to the three technologies I have previously discussed. These covers go over your license plate, keeping it visible to anyone who is directly behind your car. In certain angles, however, a portion of your license plate cannot be seen. Some states, particularly Washington, D.C, penalize the use of these covers by as much as $300. Other states are silent regarding their use. Should you ever decide to go for plate covers, note that they do not work with motion video cameras.

● Photo spray

This is the least effective method for beating photo radars. It is sprayed onto license plates. Its high gloss finish is said to reflect the light flashed by cameras, resulting in overexposure of photos. Experts warn that photo sprays are only 45% reliable in reflecting camera light. Furthermore, though photos are overexposed, a quick scrutiny of their negatives will yield the exact sequence of a license plate's numbers and letters.

Beating photo radars requires cunning and the proper tools. When caught, you would be held legally accountable. You must, therefore, carefully consider what technology to use and whether you are ready for repercussions. Then, and only then, should you use any of the above-mentioned technologies.