Wisconsin Department of Transportation

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Agricultural equipment and vehicles

Agricultural vehicle driving on the highway with a tractor sign along the edge of the highway

Wisconsin Act 377 makes several changes to the way agricultural vehicles may operate on the public roadway. The most significant changes include:


new Series of nine IoH training videos available on various aspects of the law


In general, under the new law, vehicles defined as IoH and Ag CMVs will be allowed to operate at 15 percent higher weight limits than previously allowed, or 92,000 pounds Gross Vehicle Weight (GVW) and 23,000 pounds per axle, dependent on number of axles and axle spacing and subject to seasonal or special postings. An IoH/Ag CMV Maximum Weight Limits table was created to reflect these new limits.

The definition and weight provisions are effective April 24, 2014. The No-Fee IoH/Ag CMV permit application is now available; however the application is not required to be used until Jan. 1, 2015. This application will be used by all maintaining road authorities that require a permit to operate over the new weight and length limits.

In addition to the expanded weight limit, the bill:

  • Exempts all IoH and Ag CMVs from registration.
  • Exempts empty potato harvesters, and in certain situations Category B IoH vehicles, from axle weight limits.
  • Sets new length limits for single, two- and three-vehicle combinations.
  • Requires additional lighting and marking, effective Nov. 1, 2015, for IoH that exceed 15 feet in width. Vehicles exceeding 22 feet in width will need to be accompanied by an escort vehicle.
  • Sets new width limits of ten feet for Ag CMVs, allowing up to 12 feet for certain vehicle’s fenders, fender flares or tires.
  • Creates a Self-Certification process for Ag CMVs.
  • Requires sellers of farm equipment to disclose the GVW of farm equipment, effective Jan. 1, 2015.
  • Prohibits passing of an IoH or Ag CMV in a no-passing zone.
  • Allows State Patrol to only issue warnings, not citations, for farm tractors and Category B IoH vehicles exceeding the new weight limits until Jan. 15, 2015.
    • This delayed enforcement period does not apply to violations that occur on the Interstate Highway System and does not apply to any official with the authority to enforce size or weight regulations other than State Patrol.

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