A unit of the Highway Patrol has traded in its four-wheel vehicles for the two-wheel freedom of motorcycles, taking to their Harley’s on highways across Tennessee.“They are much more mobile and agile in traffic,” explained Lt. Johnny McDonald who heads the Falcon Unit of the Highway Patrol. “They can spot certain violations easier than troopers who are in cars.”An element of the Falcon Brigade was in Warren County on Thursday afternoon to work highway enforcement. The seven-man group is among the 28 certified riders who are on the mounted portion of the Tennessee Highway Patrol.