Missouri to use military acoustic weapon to warn speeders in construction zones

The agency has been testing the deafening sonic weapons as a tool to warn inattentive drivers as they approach a mobile construction zone, such as a line-painting operation. Drivers are greeted with an alarm sound followed by a voice warning of slow vehicles ahead.

“While the product has been used for several years successfully in military and police operations, MoDOT is the first transportation department to test LRAD’s product for traffic safety.” the agency wrote in a memo (PDF).

The LRAD utilized in field trials is capable of putting out up to 153 decibels of sound through an emitter that focuses the sound, which “easily penetrates the windshield and well-insulated cab of a car, even overriding the vehicle’s engine sounds and a radio turned up loud enough to jam tunes at highway speeds.”

A video of the field tests suggests the LRAD may be continuously blaring the warnings, rather than being controlled by an operator who watches for vehicles that don’t appear to be slowing in time or moving out of the lane. It is expected to be paired with a radar device, activating automatically when a driver approaches at a high rate of speed.