No vehicle, unladen or with load, may exceed a height of thirteen feet six inches except an automobile transporter unit the height of which may not exceed fourteen feet. It is unlawful for any person to operate or attempt to operate under any underpass having a vertical clearance of less than thirteen feet six inches any vehicle with a height in excess of the vertical clearance of the underpass posted in accordance with the manual on uniform traffic-control devices provided for in Section 56-5-920. No person is required to raise, alter, construct, or reconstruct any existing underpass, wire, pole, trestle, or other structure to permit the passage of any vehicle, and neither the State nor any of its agencies or political subdivisions are liable for any personal injury or property damage resulting from the operation of a vehicle over any highway, road, or bridge or through any underpass having a vertical clearance of less than fourteen feet where the Department of Transportation or other body having maintenance jurisdiction of the underpass has posted notice of the reduced vertical clearance in accordance with the manual on uniform traffic-control devices provided for in Section 56-5-920. An automobile transporter is responsible for any personal injury or property damage resulting from operating a unit at a height in excess of thirteen feet six inches.