Privately owned motor vehicles will be driven only on those roadways designed and built for their use. Driveways and roads marked "service" may be used only by college employees in college-owned vehicles conducting official business, emergency vehicles, and authorized delivery vehicles. All other vehicles are prohibited from traveling or parking in these areas unless authorized by parking services. Brick-paved and other designated areas are for pedestrian and bicycle traffic only, except as needed for emergency vehicles or for maintenance of buildings or grounds. No person without authorization from the director of facilities or the director of police services will install, move, deface, or in any way change a sign, barricade, structure, marking or direction so placed, or previously placed, for the purpose of regulating traffic or parking.