Michigan Compiled Laws, Chapter 257. Motor Vehicles § 257.1859

Sec. 59. (1) A driver of a school bus shall not transport or permit to be transported on a school bus while transporting pupils to and from school an individual other than pupils, individuals enrolled in a school-sponsored preschool program authorized by state or federal statute, teachers or chaperons of the pupils or other individuals authorized by the school for the protection of property or the health, safety, and welfare of the pupils or individuals attending other school related functions, or both. This subsection does not apply during the transportation of individuals under section 65.  1

(2) After the fourth Friday following Labor Day of each school year, a school bus must not be used to transport more than 100% of the number of individuals for which the school bus has a rated seating capacity.

(3) A person that violates or directs a violation of subsection (1) or (2) is responsible for a civil infraction and may be ordered to pay a civil fine of not more than $100.00. A civil infraction under this subsection must be processed in the same manner as a civil infraction under the Michigan vehicle code, 1949 PA 300, MCL 257.1 to 257.923.

(4) An individual other than an authorized person shall not enter a school bus without the permission of the driver of the school bus. As used in this subsection, “authorized person” means any of the following:

(5) A person shall not impede the progress or operation, or both, of a school bus.

(6) A person that violates subsection (4) or (5) is responsible for a civil infraction and may be ordered to pay a civil fine of not more than $500.00. A civil infraction under this subsection must be processed in the same manner as a civil infraction under the Michigan vehicle code, 1949 PA 300, MCL 257.1 to 257.923.