Section R. 247.709 - MeasurementsRule 9.
(1) Measurements for spacing determination shall be made parallel to the edge of the pavement of the main traveled way.(2) Measurements for determining that portion of a business area that is within 1 mile of a municipality shall be made on an arc or radius basis, with measurements starting at the nearest point on the corporate limits and extending toward the controlled highways.(3) Measurements between multiface signs shall be horizontal between the edge or back of the display face or face border trim of the sign and sign structure.(4) The following shall be deemed 1 sign structure for spacing and size controls if they comply to the stated criteria: (a) Double-faced display; faces lying in the same general plane not more than 4 feet apart and facing the same direction of travel.(b) Back-to-back sign structure; faces not more than 10 feet apart and facing in opposite directions of travel.Mich. Admin. Code R. 247.709