Michigan Oversize/Overweight Permits

Michigan
PERMITS
Michigan oversize permits are valid for five travel days. You must have a 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 10wide, 14′  high, and 90long. No weekend travel when dimensions are greater. However, continuous travel is allowed for overweight-only loads with all other dimensions legal and a length not exceeding 70.

LEGAL DIMENSIONS

Width:
  • 8’6″ designated highways
  • 8’0″ all other roads
Height:  13’6″
Weight: 80,000 lbs. gross weight:
  • Steer Axle – 700 lbs. per inch of tire width (15,400 lbs. with 11″ tires)
  • Single – 20,000 designated highways (18,000 on other roads)
  • Tandem – 34,000 lbs. (32,000 on non-designated roads, and 26,000 on second tandem)
  • Tridem – 42,000 lbs. (39,000 on non-designated)
Length:
  • 53′ semi-trailer on Interstate and designated highways
  • 50′ maximum on non-designated highways

PERMIT LIMITS

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.
Length: 150′
Loads exceeding these dimensions must apply for superload permits and may take up to ten days to issue once shipper letter, route surveys, etc. are received.

ESCORTS FOR WIDELOAD AND OVERSIZED SHIPPING

When Escorts are Needed (On All Highways):

Height over 14’5″ 1 escort with high pole
Height over 15′ 2 escorts and a route survey must be submitted for approval
Length over 90′ 1 escort
Length over 100′ 2 escorts (front and rear)
Overhang over 14′ 1 escort
Width over 12′ 1 escort
Width over 14′ 2 escorts
*Route Survey: Applications for permits in excess of 13’6″ in height shall certify that the proposed route has been traveled to assure vertical clearance. Lift Axles:  According to the Michigan state provision sheet, vehicles must have air or lift axles on the ground. According to the permit office, when under a load, all axles including flip axles must be on the ground if you are overweight.

SIGNS, FLAGS & LIGHTS

“Oversize Load” signs are required on the front of a vehicle and on the rear of the load for any over-dimensional load in Michigan. 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 the rear overhang is 4or more, the extreme rear of the load must have a flag for daytime running and a red light or lantern at night.

RESTRICTED TRAVEL

Loads over 12′ wide or 90′ long are not to move from 7:00 a.m. to 9:00 a.m. and from 3:00 p.m. to 6:00 p.m. 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:

Note on Bridge Crossings: Contact the Mackinaw Bridge Authority (phone: (906) 643-7600) 24 hours prior to the planned bridge arrival/crossing. For loads that exceed the legal weight limit or are wider than 10 feet, an escort will be provided at no cost. Crossing is not allowed when winds exceed 25 mph. The Ambassador Bridge (between Detroit and Windsor, Ontario) is now charging $50.00 or more for overdimensional shipments and may require a one-day notice. They have restricted crossing hours from 10:00 a.m. to 4:00 p.m., Monday through Friday. The Ambassador Bridge phone number is (313) 496-1111.

You can also obtain any trip and fuel permits you may need with our sister site!