Michigan Pilot Car Services

PERMITS
Michigan oversize permits are valid for five travel days and must be secured before entering the state.

OPERATING HOURS
Standard operating hours are from sunrise to sunset. Weekend travel is currently allowed on a trial basis for loads not exceeding 10 feet wide, 14 feet high, and 90 feet in length — permitted from daylight until 3:00 PM on Saturdays and Sundays. Overweight-only loads with legal dimensions and total length not exceeding 70 feet may operate 24/7.

RESTRICTED TRAVEL
Loads exceeding 12 feet in width or 90 feet in length are not permitted to travel between 7:00 AM – 9:00 AM and 3:00 PM – 6:00 PM in the following counties: Genesee, Ingham, Jackson, Kalamazoo, Kent, Muskegon, Macomb, Oakland, Saginaw, Washtenaw, and Wayne. No travel is permitted on major holidays or holiday weekends.

BRIDGE CROSSING NOTES

• Mackinac Bridge: Contact the Mackinac Bridge Authority (906-643-7600) 24 hours in advance. Escorts are provided at no cost for loads over legal weight or wider than 10 feet. No crossings are allowed when wind speeds exceed 25 mph.
• Ambassador Bridge (Detroit to Windsor, Ontario): Charges $50+ for oversize/overweight shipments and may require one-day notice. Permitted crossing hours are 10:00 AM to 4:00 PM, Monday through Friday. Contact: 313-496-1111.

LEGAL DIMENSIONS

Length:

• 53-foot semi-trailer allowed on Interstates and designated highways (must have a kingpin-to-rear-axle setting of 41 feet)
• 50-foot maximum on non-designated roads

Width:

• 8 feet 6 inches on designated highways
• 8 feet on all other roads

Height: 13 feet 6 inches

Gross Weight: 80,000 pounds

• Steer axle: 700 pounds per inch of tire width (15,400 pounds with 11" tires)
• Single axle: 20,000 pounds (18,000 on non-designated roads)
• Tandem: 34,000 pounds (32,000 non-designated; 26,000 on second tandem)
• Tridem: 42,000 pounds (39,000 on non-designated roads)

ROUTINE PERMIT LIMITS

Length: 150 feet
Width: 16 feet (reduced to 14 feet during spring thaw restrictions)
Height: 15 feet
Shipper and driver are responsible for route safety when load exceeds 13 feet 6 inches in height.

Weight:
Handled case-by-case. Air or lift axles must be deployed. Vehicle must be registered for the total permitted weight. Superload applications may take up to 10 days and require route surveys, letters, and additional documentation.

ESCORT REQUIREMENTS

Length:

• Over 90 feet: 1 escort
• Over 100 feet: 2 escorts
• Overhang over 15 feet: 1 escort

Width:

• Over 12 feet: 1 escort
• Over 14 feet: 2 escorts

Height:

• Over 14 feet 5 inches: 1 escort with high pole
• Over 15 feet: 2 escorts plus approved route survey

LIFT AXLES:
All axles, including flip axles, must be on the ground when hauling overweight loads, per Michigan's permit provisions.

SEASONAL LOAD RESTRICTIONS
Typically in effect February through April. Overweight permits are not issued during this period. Axle group weight limits may be reduced by up to 35%. Example: Tandem axles may be limited to 26,000 pounds total (13,000 per axle). Frost Law Hotline: 800-787-8960

SIGNS, FLAGS & LIGHTING

• “Oversize Load” signs are required on the front of the vehicle and rear of the load for any oversize movement
• Red flags must be placed on each corner of any overwidth or overlength load, with additional flags at the widest point if the load extends beyond the corners
• For rear overhangs of 4 feet or more:
  • Daytime: flag required at the extreme rear
  • Nighttime: red light or lantern required