Flatbed and steel trucking in Michigan: permits and insurance touchpoints
MDOT issues transport permits for loads over Michigan's legal size or weight that cannot reasonably be reduced. MDOT's permit rules say the insurance required by state law must be in effect for the move; they do not ask for a separate state filing like Ohio's OS-32. Permits are single trip unless stated, and overweight permits are not valid during spring weight restrictions.
- Transport permits
- The insurance condition
- Spring restrictions
- Securement and federal rules
- FAQ
Steel, machinery and building loads in Michigan can run near the legal limits. Here are the Michigan touchpoints, with the official source for each.
Transport permits
- MDOT issues transport permits only for loads that cannot reasonably be reduced in size or moved another way (MDOT oversize and overweight permits).
- Permits do not cover county roads or city streets. Ask those road agencies separately (MDOT permit conditions).
The insurance condition
- Insurance required by Michigan law must be in effect for any permitted move (MDOT oversize and overweight information). MDOT's rules do not name a separate state insurance filing.
Spring restrictions
- Overweight permits are not valid during the spring weight restriction period (MDOT permit conditions).
Securement and federal rules
- Coils follow the federal metal coil rules in every state (49 CFR 393.120). See flatbed cargo securement and steel coils.
- Interstate for-hire carriers keep federal proof of insurance on file with FMCSA (49 CFR 387.303T).
- Plants and mills may ask for certificates. See certificates of insurance for mills and plants.
For general freight in Michigan, see the dry van state note.
FAQ
Does MDOT require an insurance filing for a transport permit?
MDOT's permit rules say insurance required by state law must be in effect for the move. They do not name a separate filing like Ohio's OS-32.
Are Michigan overweight permits valid in spring?
Not during the spring weight restriction period, per MDOT's permit conditions.
Does an MDOT permit cover local roads?
No. County roads and city streets need permission from those authorities.
This guide is general information, not advice on any policy.
Sources
- MDOT: Oversize and overweight permits (accessed Oct 29, 2026)
- MDOT: Information on the movement of oversize or overweight vehicles and loads (PDF) (accessed Oct 29, 2026)
- MDOT: Permit special provisions, conditions and restrictions (PDF) (accessed Oct 29, 2026)
- 49 CFR 393.120: Securing metal coils (last amended Nov 18, 2024)
- 49 CFR 387.303T: Security for the protection of the public: Minimum limits (last amended Sep 30, 2019)