Mich. Comp. Laws § 257.20c: "High-occupancy vehicle lane" or "HOV lane" defined.

Sec. 20c.

"High-occupancy vehicle lane" or "HOV lane" means any designated lane or ramp on a highway designated for the exclusive or preferential use of a public transportation vehicle or private motor vehicles carrying no fewer than a specified number of occupants, including the driver of the vehicle.