Permits
Michigan oversize permits are valid for five travel days. Must have permit prior to entering the state.
Operating Time
Sunrise to sunset. Weekend travel is now being permitted on a trial basis for loads not exceeding 10′ wide, 14′ high, and 90′ long. Saturday and Sunday daylight to 3:00 pm. If overweight only with all dimensions legal and not exceeding 70′ overall length can have continuous travel.
Restricted Travel
Loads over 12′ wide or 90′ long are not to move from 7:00 am – 9:00 am and from 3:00 pm – 6:00 pm in the following counties: Genesee, Ingham, Jackson, Kalamazoo, Kent, Muskegon, Macomb, Oakland, Saginaw, Westenau, Wayne. No travel on major holidays and holiday weekends.
Note on Bridge Crossings: Contact Mackinaw Bridge Authority (phone 906-643-7600) 24 hours prior to planned bridge arrival/crossing. Escort will be provided (no charge) for loads exceeding legal weight or 10′ wide. Crossing is not allowed when winds exceed 25 miles per hour. Ambassador Bridge (between Detroit and Windsor, Ontario) is now charging $50.00 or more for O/D shipments and may require a one-day notice. They have restricted crossing hours from 10:00 am to 4:00 pm, Monday through Friday. Ambassador Bridge phone is 313-496-1111.
Legal Dimensions
Length: 53′ semi-trailer on Interstate and designated highways. 53′ trailer must have kingpin setting of 41′. 50′ maximum on non-designated highways.
Width: 8′-6″ designated highways. 8′ all other roads.
Height: 13′-6″
Weight: 80,000 Gross
Steer Axle – 700 pounds per inch of tire width (15,400 pounds with 11″ tires)
Tandem – 34,000 (32,000 on non-designated roads, and 26,000 on second tandem)
Tridem – 42,000 (39,000 on non-designated)
Single – 20,000 designated highways (18,000 other roads)
Routine Permit Limits
Length: 150′
Width: 16′ (or 14′ during spring thaw restrictions)
Height: 15′ Shipper/driver are responsible for finding safe routes when the height exceeds 13’6″
Weight: “Handled on a case-by-case basis.” Air or lift axles should be on the ground. You must be registered for at least the amount of weight you are permitting for Michigan.
Loads exceeding these dimensions must be applied for as superloads, and may take
up to ten days to issue once shipper letter, route surveys, etc. are received.
Escorts
Length:
Over 90′ – one escort
Over 100′ – two escorts
Overhang: Over 15′ – one escort.
Width:
Over 12′ – one escort
Over 14′ – two escorts
Height:
Over 14′-5″ – one escort with high pole
Over 15′ – two escorts and a route survey must be submitted and approved.
Lift Axles: According to Michigan provision sheet, “Vehicles must have air or lift axles on ground.” According to the permit office, when under a load, all axles including flip axles must be on the ground if you are overweight.
Seasonal Load Restrictions
Usually February to April, maximum weights per axle and specific routing may vary. No overweight permits will be issued during the spring weight restriction period. Maximum axle weights may be reduced up to 35%. A tandem group may be allowed only 26,000 pounds (13,000 pounds per axle), or with two tandem groups they may allow 26,000 pounds for one group and 32,000 for the other tandem group. Frost Phone: 800-787-8960
Signs, Flags & Lights
“Oversize Load” signs required on front of vehicle and on rear of load for any overdimensional load. An overwidth or overlength vehicle/load requires flags at each corner of the load, with an additional flag at the widest point on each side of the load if it extends beyond the corner flags. When rear overhang is 4′ or more, the extreme rear of the load must have a flag for daytime running, and a red light or lantern at night.
