Michigan Compiled Laws, Chapter 460. Public Utilities § 460.204

Sec. 4.If any complaint is made to the department of state police by any person, firm, or corporation against any rate, fare, charge, or tariff of any carrier by water within this state, or against any rule or regulation of a carrier by water or against the neglect, failure, or refusal of a carrier by water to make, observe, or perform any rate, fare, charge, or tariff, or any rule or regulation, the department of state police shall investigate the matter, and the department may regulate the performance or observance of any rate, fare, charge, or tariff, and any rule or regulation, and may require the carrier to observe the rate, fare, charge, or tariff and any rule or regulation. A carrier by water is in all cases entitled to reasonable notice and an opportunity to be heard on an investigation before any rate, fare, charge, or tariff, or any rule or regulation is prescribed, established, or imposed by the department of state police as provided in this section, and if any rate, fare, charge, or tariff, or any rule or regulation is prescribed, established, or imposed by the department of state police, the carrier by water shall observe and obey the same.