After the mention of cargo vans with no rear windows I looked up Michigan law. I found this. I did not post the entire document. If you only had one outside rearview mirror on the drivers side you would probably be SOL but two mirrors are pretty much standard these days.
MICHIGAN VEHICLE CODE (EXCERPT)
Act 300 of 1949
257.709 Windshields and windows; prohibitions; rearview mirrors; exceptions; windshield wipers; exemption; hot air windshield defroster or electrically heated windshield or other device; windshield device; definitions.Sec. 709.
(1) A person shall not operate a motor vehicle with any of the following:
(a) A sign, poster, nontransparent material, window application, reflective film, or nonreflective film upon or in the front windshield, the side windows immediately adjacent to the driver or front passenger, or the sidewings adjacent to and forward of the driver or front passenger, except that a tinted film may be used along the top edge of the windshield and the side windows or sidewings immediately adjacent to the driver or front passenger if the material does not extend more than 4 inches from the top of the windshield, or lower than the shade band, whichever is closer to the top of the windshield.
(b) A rear window or side window to the rear of the driver composed of, covered by, or treated with a material that creates a total solar reflectance of 35% or more in the visible light range, including a silver or gold reflective film.
(c) An object that obstructs the vision of the driver of the vehicle, except as authorized by law.
(2) A person shall not drive a motor vehicle if driver visibility through the rear window is obstructed, unless the vehicle is equipped with 2 rearview mirrors, 1 on each side, adjusted so that the operator has a clear view of the highway behind the vehicle.
(3) This section does not apply to any of the following:
(a) The use of draperies, louvers, or other special window treatments, except those specifically designated in this section, on the rear window, or a side window to the rear of the driver if the vehicle is equipped with 2 outside rearview mirrors, 1 on each side, adjusted so that the driver has a clear view of the highway behind the vehicle.