Michigan § 257.708 - Mirrors.

A person shall not drive a motor vehicle on a highway which is so constructed or loaded as to prevent the driver from obtaining a view of the highway to the rear by looking backward from the driver's position, unless the vehicle is equipped with a mirror located so as to reflect to the driver a view of the highway to the rear of the vehicle. In addition all motor vehicles shall be equipped with an outside rearview mirror on the driver's side which shall be positioned to give the driver a rearviewing angle from the driver's side of the vehicle, except a motor vehicle licensed as an historic vehicle if the vehicle was not originally equipped with an outside rearview mirror. Rearview mirrors may be positioned on the helmet or visor worn by the operator of a motorcycle if the helmet is securely attached to the head of the operator. Every commercial vehicle of 1/2 ton capacity or more, operating upon the public highways of this state, shall be equipped with 2 mirrors, 1 on each side, adjusted so that the operator shall have a clear view of the highway behind the commercial vehicle. The outside mirrors shall not be considered to be a part of the vehicle for the purpose of determining the maximum width under section 717.