Mich. Comp. Laws § 257.791f: Oversized baggage or commercial shopping cart prohibited on or within a streetcar or station.

Sec. 791f.

A person shall not bring or carry on a streetcar or into a station used by a street railway system either of the following:

(a) A package or other object of a size that cannot be positioned in a manner that permits the passage of persons in the aisle of a streetcar or the entry and exit of persons through the doors of a streetcar, or both.

(b) A commercial shopping cart.