IoH – Size Dimensions


  • No width limitations when operated or towed but additional width requirements when trailered.
  • Additional lighting and marking requirements for wide IoH were effective November 1, 2015.
  • Also applies for IoH being operated, towed or trailered for delivery, service, or repair by dealer or farmer within 75-mile radius of business or farm.


  • No height limitations for IoH operating or towed on any highway or when trailered..
  • Operator of IoH remains responsible for ensuring safe clearance of any overhead obstructions.


For vehicles or vehicle combinations that exceed these length limits, a No Fee Permit may be available.

  • Single Vehicle maximum length is 60 feet.
  • 2 vehicle combination (one towed IoH unit drawn by an IoH power unit) has a maximum length of 100 feet.
  • 3 vehicle combination or agricultural trains– two towed IoH units and power unit.
    • No more than 100 feet with speed restriction of 25 mph or less or 70 feet at a speed greater than 25 mph.
    • Towed IoH units being drawn by a motor truck, truck tractor, or agricultural commercial motor vehicle (Ag CMV) must be empty. “Empty” means less than 20% full.
    • Additional lighting and marking requirements apply on agricultural trains.

Exception: Irrigation System

There is no length limit for an irrigation system being towed by a farm tractor, farm truck, farm truck tractor or motor truck temporarily operated upon a highway.  [s. 348.07(2)(e)3 Wis. Stats.]


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