Michigan Oversize Load Permits, Regulations & Axle Rules

Michigan restricts all standard permitted loads to daylight hours, Monday through Friday. Daylight is defined as the window from one-half hour before sunrise to one-half hour after sunset; that half-hour buffer on each end is codified, not a guideline. Saturday and Sunday travel is not allowed under a standard single-trip permit. There is no published exception for overweight-only or legal-size loads to run outside that daylight-weekday window, and no continuous 24-hour movement authorization appears in the source material.

Six holidays generate hard travel blackouts. For standard permits, movement is prohibited from noon on the day before each holiday through the first full daylight after the holiday ends. When the holiday falls on a Friday or Monday and creates a three-day weekend, the no-travel period stretches across the entire weekend, from noon on the Thursday or Friday before through daylight on the Tuesday after. The six holidays are New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving, and Christmas.

Annual construction equipment permits carry a lighter holiday schedule: only Memorial Day, Independence Day, and Labor Day. That category has no blackout around Thanksgiving, Christmas, or New Year's.

Michigan does not publish metro rush-hour curfews for permitted loads. Any move may be halted at any time if MDOT or a policing agency determines that traffic, weather, or other conditions have created a hazard, and drivers are expected to comply and wait. No weather or visibility thresholds are written into the permit conditions, but the state's authority to halt movement is explicitly tied to hazard conditions.

Michigan has a well-developed special-commodity framework built around a handful of major categories, each with its own distinct dimensional limits.

Agricultural equipment may move without a permit entirely when being driven or towed, as long as it maintains the minimum posted speed. Where a permit is needed, the extended annual agricultural permit allows up to 15'6" wide, 14 feet high, and 80 feet overall, at legal weight.

Construction equipment on a single-trip permit follows the general maximums (16' wide, 15' high, 150' overall). On the extended annual, the maximums tighten to 12'6" wide, 14 feet high, 85 feet overall, with a 150,000-lb gross weight cap and 24,000 lbs per axle. Empty self-propelled scrapers, rubber-tired loaders and dozers, and two-axle mobile cranes are exempt from the 24,000 lb/axle limit under the annual; they're governed instead by an 850 lbs per inch of tire tread width cap.

Saw logs, pulpwood, and tree-length poles get structural relief. A truck-tractor and semitrailer used to haul saw logs may carry a rear overhang up to 6 feet if the semitrailer does not exceed 50 feet in length. A crib vehicle and semitrailer combination used to haul saw logs has an overall length ceiling of 75 feet and a gross weight ceiling of 164,000 lbs, both codified as legal, not permit-dependent.

Auto transporters have distinct length and overhang allowances: a stinger-steered unit may run up to 80 feet overall, with the load allowed to extend an additional 4 feet beyond the front and 6 feet beyond the rear of the combination. A non-stinger auto transporter is limited to 65 feet overall, with a 3-foot front extension and 4-foot rear extension. A 53-foot trailer unit used exclusively for assembled motor vehicles may have the load extend 3 feet beyond the trailer front and 4 feet beyond the trailer rear, with a total loaded length cap of 79 feet.

International sealed shipping containers on a single-trip permit are capped at 8'6" wide, 13'6" high, 60 feet of overall length, 95,000 lbs gross, and 24,000 lbs on any single axle. The load must be USDA sealed; no extended permit is available for this category.

Snowplows get a seasonal exemption: a snowplow blade between 96" and 132" wide may operate without a permit from October 1 through May 1 each year. This exemption does not apply on interstates and does not cover construction equipment used for snow removal.

Poles and pipes (as a class) are handled under an annual permit capped at 8 feet wide, 13'6" high, and 85 feet overall, at legal weight. Public utility companies have a specific allowance to move at up to 150 feet of overall length within their service area, provided written confirmation from the utility is on file.

Michigan does not publish commodity-specific seasonal windows beyond the spring restriction period's width cap and the snowplow exemption's October to May window.

Michigan uses the standard term Superload. Any load that exceeds the ceiling of a normal single-trip permit becomes a superload. The three triggers are: width greater than 16 feet, height greater than 15 feet, or overall combination length greater than 150 feet. Michigan defines no weight-based superload threshold; the state has no gross weight tier that by itself pushes a load into superload status regardless of its dimensions.

The superload process is manual and front-loaded with documentation, and Michigan is direct about its posture: carriers should exhaust every alternative first (rail, water, or a longer route that avoids state trunklines) before requesting a superload permit. A feasibility argument is part of the submission. The paperwork package has three required elements: (1) a complete written explanation on company letterhead, (2) a properly completed application submitted through MiTRIP, Michigan's online permitting system, and (3) a Route Survey Certification, a specific state form (Form 2465). All documentation must reach the Lansing Transport Permit Office no fewer than 10 working days before the tentative movement date.

MDOT reviews and approves superload applications. The permit is issued for a specific route, which MiTRIP generates based on the load configuration. There is no published fee schedule tier specific to superloads; the standard single-trip fee schedule applies. Michigan does not specify travel windows unique to superloads in the available source material, and whether police escort is required on a given superload is handled at the individual permit level rather than by a fixed published threshold (see the Police Escort section below).

Michigan operates two distinct levels of route review depending on how large the load is.

For loads where the height exceeds 14'6", MiTRIP automatically assigns Provision 2 to the permit: "Route to be checked for vertical clearance and overhead obstructions prior to movement." At the same threshold, a front escort with a fixed height-measuring device, set to the actual height of the load, is required to physically verify clearance at each overhead obstruction before the load passes under it. This is a carrier-performed obligation, enforced through a system-generated permit condition. It applies once the load is taller than 14 feet 6 inches and continues up to the superload wall at 15 feet 1 inch, above which MiTRIP rejects the application and the superload process applies.

For formal superloads (any load over 16 feet wide, over 15 feet high, or over 150 feet in overall length), a Route Survey Certification (Form 2465) is a mandatory document that must be submitted with the superload application, at least 10 working days before the move. This is a separate, formal survey distinct from the system-generated Provision 2 route check. The Route Survey Certification must be on file before the permit can issue; without it, the application is incomplete.

Michigan's sources do not specify exactly what Form 2465 must document beyond the certification itself, and the state does not describe this as a state-performed survey: responsibility for completing and certifying the form falls on the carrier or permittee. There are no independently published survey requirements for loads that fall below the superload triggers but above the Provision 2 height check, other than what system-generated permit provisions may impose on a case-by-case basis. MDOT also requires an approved route from the local Transportation Service Center (TSC) before issuing a permit for a hydraulic boat lift trailer.

Michigan's Michigan State Police (MSP) is the agency that provides law enforcement escort when escort is required. Michigan does not publish a fixed dimensional or weight threshold that codifies when a police escort is mandatory on a standard oversize or overweight permit. No table of breakpoints exists in any source document. The sources treat police escort as discretionary, addressed on a move-by-move basis through individual superload permits or supplemental administrative guidance not included in Michigan's publicly available permit materials.

Escort requirements in Michigan's published materials are split between civilian/pilot escort and a separate lane reserved for law enforcement. For the codified civilian escort tiers: any load over 12 feet wide requires one escort vehicle on all road types (on roads with four or more lanes, the escort follows behind the load; on roads with fewer than four lanes, it leads in front). Once width exceeds 14 feet, two escorts are required, one in front and one behind. Height over 14'6" triggers a front pole-escort. Overall combination length over 100 feet triggers one escort vehicle. These tiers are codified through MiTRIP's provision system and confirmed through portal testing.

Escort vehicles must be passenger vehicles (a pickup truck qualifies), equipped with at least one flashing or rotating amber light on top of the cab visible from 500 feet, and displaying an "OVERSIZE LOAD" sign 5 feet long by 12 inches high with 8-inch black letters on a yellow background. Because no published breakpoint governs when MSP must be involved, carriers planning superloads or exceptionally large moves should confirm police escort requirements during the permitting process with the Lansing Transport Permit Office: arrangements are made through permitting, not independently with MSP.