Mich. Comp. Laws § 247.404

Sec. 4. (1) The size, location, design, and arrangement of each tourist-oriented directional sign subject to this act shall conform to the specifications for signs contained in the state manual of uniform traffic control devices. (2) The department shall develop optional, standardized symbols for different types of activities associated with eligible attractions. The symbols may be used on signs in conjunction with other directional information. If more than 1 eligible attraction requires a sign at the same location, multiple signs may be combined on the same panel in accordance with the state manual of uniform traffic control devices. (3) Signs governed by this act may be erected at locations the department determines appropriate to ensure adequate sight distance, intersection vehicle maneuvers, and public safety.