Each year, several thousand fatal auto accidents occur in the United States that involve drivers who aren't even supposed to be on the road-their licenses have been suspended or revoked. Gaithersburg, Md.-based Multispectral Solutions has developed a credit-card-sized radio transmitting tag that could bag these illegal drivers.

The tag, developed with the U. S. Department of Transportation, mounts on the unlicensed driver's car. It constantly broadcasts an ultra-wideband (UWB) radio signal containing a digital picture of the banned driver, along with information about the car and the driver's record. Composed of nanosecond pulses, a UWB signal is immune to the interference that longer signals suffer when they bounce off nearby surfaces. A tag reader at roadside or in a police car sounds an alert and displays the transmitted data, giving police the chance to check the face behind the wheel against the face on the screen.