WEST BRIDGEWATER, Mass. — State troopers in Chattanooga, Tennessee, have been known to patrol in a tractor-trailer so they can sit up high and spot drivers texting behind the wheel. In Bethesda, Maryland, a police officer disguised himself as a homeless man, stood near a busy intersection and radioed ahead to officers down the road about texting drivers. In two hours last October, police gave out 56 tickets.