Sec. 161. (a) "School bus" means, except as provided in subsection (b), a bus used to transport preschool, elementary, or secondary school children to and from:
(1) school;
(2) school athletic games or contests; or
(3) other school functions.
(b) "School bus", for purposes of IC 9-21, means a motor vehicle owned by a public or governmental agency and operated for the transportation of children to or from school, including project headstart, or privately owned and operated for compensation for the transportation of children to and from school, including project headstart.