Sec. 21. (a) "Chauffeur", except as provided in subsection (b), means a person:
(1) operating a motor vehicle registered as having a gross weight of at least sixteen thousand (16,000) pounds but not more than twenty-six thousand (26,000) pounds for the purpose of transporting property for hire; or
(2) operating a private bus.
(b) "Chauffeur", for purposes of IC 9-25, means a person:
(1) who is employed for hire for the principal purpose of operating a motor vehicle upon the highways;
(2) who operates a motor vehicle while in use as a carrier of passengers or property for hire; or
(3) who drives or operates a motor vehicle while in use as a school bus for the transportation of pupils to or from school.