It's a civilian version of electronic warfare--where each advance is met by a countermeasure. First, police got radar to trap speeding motorists. Then came the radar detector. So, to nab lead-footed drivers, police are beginning to use laser guns. But even before laser guns are common, Cincinnati Microwave Inc. (CMI) has unveiled a detector to foil them.
To determine a car's speed, the cops' laser gun computes the difference between the time for each infrared light pulse to bounce off a target and return. In place of a radar antenna, the new detector has a photosensitive cell. The system alerts speeders by beeping and flashing a light.
There are rays of hope for the police: Only about 300 laser guns are in use, and CMI says it won't be economical to mass-produce laser detectors until that number increases tenfold. And the rivalry isn't over. CMI says its device can detect laser pulses up to two miles away. But Laser Technology Inc., a laser-gun manufacturer in Englewood, Colo., claims that such detectors won't be able to warn speeders in time.