DOUGLAS COUNTY, Georgia - September 29, 2010 - A team of federal agents stopped tractor-trailers on Interstate 20 just west of Atlanta, inspecting each truck as it passed through a weigh station, and Channel 2 has learned its part of a counter-terrorism operation.

Channel 2's Linda Stouffer reported a flashing sign on the interstate directed the trucks to pull into a state-owned inspection station near Lee Road in Douglas County at the height of the evening commute.

Channel 2 Action News confirmed that agents from several federal agencies, including Homeland Security, the Department of Transportation, and the Transportation Security Administration were involved. The Douglas County Sheriff’s Office assisted in the exercise.

A TSA spokesman told Channel 2 the event is known as Visible Inter-mobile Prevention and Response, or VIPER, an operation that is conducted with local authorities as a training exercise. The TSA spokesman said the operation is not in response to a specific threat.

However, federal sources told Channel 2 investigative reporter Mark Winne the inspections are part of a counter-terrorism operation.

News Chopper 2 showed screening devices, dogs and a large drive-through bomb detection machine in use along the eastbound interstate near Lee Road.

Trucks were being sorted into two lines, one with more rigorous screening. Agents used a variety of devices to check the exteriors of the trailers, including a large drive-through machine similar to a security tool used at the Super Bowl, and a tool that measures radiation.