As Interstate 95 sweeps past this small town along South Carolina's coastal plain, motorists encounter cameras that catch speeding cars, the only such devices on the open interstate for almost 2,000 miles from Canada to Miami. The cameras have nabbed thousands of motorists, won accolades from highway safety advocates, attracted heated opposition from state lawmakers and sparked a federal court challenge. Ridgeland Mayor Gary Hodges said the cameras in his town about 20 miles north of the Georgia line do what they are designed to do: slow people down, reduce accidents and, most importantly, save lives. But lawmakers who want...