(a) Except as authorized in subsection (b) of this Code section and except when so authorized by a permit issued pursuant to Code Section 32-6-28, no vehicle unladen or with a load shall exceed a height of 13 feet, six inches.

(b) On highways which constitute a part of The Dwight D. Eisenhower System of Interstate and Defense Highways as such term is used in 23 U.S.C. Section 127 and ramps or service streets which provide reasonable access thereto, no vehicle transporting motor vehicles (commonly known as automobile carriers) unladen or with a load shall exceed a height of 14 feet.