Agricultural Commercial Motor Vehicles (Ag CMVs)

Width | Height | Length | Weight | Trailering

Definition

Wisconsin Statute s. 340.01(1o) law specifically defines an "Agricultural commercial motor vehicle" (Ag CMV) as a commercial motor vehicle to which all of the following apply:

  • The vehicle is substantially designed or equipped, or materially altered from its original construction, for the purpose of agricultural use.

    Ag CMV​​
    Example of Ag CMV
    Photo credit: UW Extension

  • The vehicle was designed and manufactured primarily for highway use.
  • Unless the vehicle was manufactured prior to 1970, the vehicle was manufactured to meet federal motor vehicle safety standard certification label requirements as specified in 49 CFR 567.
  • The vehicle is used exclusively in the conduct of agricultural operations.

  • The vehicle is being used in any of the following ways:

    1. For directly distributing feed to livestock or for directly applying fertilizer (but not manure), lime, spray, or seeds to a farm field. (Also called Category 1)
    2. For assisting another vehicle directly harvesting farm products by receiving farm products as they are harvested or for assisting another vehicle directly planting potatoes by delivering seed potatoes to the planter. (Also called Category 2)
    3. For directly applying manure to a farm field or for off-loading manure if field conditions do not permit application by the vehicle directly to the field. (Also called Category 3)

Ag CMV Self-Certification

A self-certification process for Ag CMVs was also created. The Ag CMV Self-Certification is not required. It is provided as a convenient reference for operators and law enforcement.

View the AgCMV self-certification form

Ag CMV Dimensions

The following dimension and weight limits were created for Ag CMVs:

Width

  • Width limit is 10 feet including attachments or accessories
  • Pesticide sprayers, lime and fertilizer spreaders (not including manure) with extending tires, fenders and fender flares may not exceed 12 feet in width.
  • These width limits are not applicable on interstate highways. The width limit for Ag CMVs on interstate highways is 8 feet, 6 inches. An Ag CMV over 8.5 feet wide requires an oversize permit to operate on interstate highways.

Height

  • 13 feet 6 inches

Length

  • Single vehicle
    • 45 feet
    • No-Fee permit may be required over 45 feet
  • Two vehicle combination – one towed unit driven by a power unit
    • 70 feet
    • No-Fee permit may be required over 70 feet
  • Three vehicle combination - two towed units drawn by a 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.
    • No-Fee permit may be required if exceeding 100 feet in length.
    • Towed units being drawn by a motor truck, truck tractor, or agricultural commercial motor vehicle must be empty. "Empty" means less than 20 percent full. (s. 348.08(1)(d), Wis. Stat.)

Weight

  • IoH/Ag CMV Maximum Weight Limits table applies: A maximum single axle weight of 23,000 pounds and a gross vehicle weight of 92,000 pounds dependent on number of axles and axle spacing.
  • These higher weight limits are not allowed on interstate highways. (s. 348.15(9)(c)2.(d), Wis. Stat.) However, I-41 travel is exempted from this provision.
  • Ag CMV - Category 1 that directly distribute feed to livestock or directly apply fertilizer (but not manure), lime, spray, or seeds to a farm field are:
    • Exempt from axle weight limits on local roads unless local government authority passes ordinance or resolution limiting Ag CMV axle weight.
    • Exempt from gross vehicle weight and axle weight limits when operating between fields and operated on the highway for a distance of 1/2 mile or less.
  • A No Fee Permit may be required if gross vehicle weight or axle weight is greater than the IoH/Ag CMV weight table.
  • All operators must abide by seasonal or other special postings.
  • Exemptions:
    • Ag CMVs traveling for delivery, service, repair by dealer or farmer within 75-mile radius of business or farm are exempt from gross vehicle weight and axle weight limits. Exemptions also pertain to Class B highways.

Trailering Ag CMVs

Operators are allowed to transport Ag CMVs on trailers or semi-trailers to and from farm-related destinations under the same weight limits that are allowable for the Ag CMV being operated on the highway. If the 2-vehicle combination transporting an Ag CMV exceeds the Ag CMV axle weight or gross weight limits, the operator may apply for a no-fee permit.

The weight exemption described above for Ag CMV - Category 1 also applies if it is transported by a 2 vehicle combination via trailer or semi-trailer to or from a farm-related destination.

Ag CMVs up to 12 feet wide are allowed to be trailered without a permit, except on interstate highways. On interstate highways, an oversize permit is required to trailer Ag CMVs over 8 feet, 6 inches wide. Review the safety webpage for lighting and marking requirements for trailered vehicles. 

To trailer an Ag CMV that exceeds the above dimensions on a local road, contact the local maintaining authority for information.

Contacts

For questions and information on IoH and Ag CMV:

Wisconsin Department of Transportation
P.O. Box 7980
Madison WI 53707-7980

Email AgVehicles@dot.wi.gov
Phone (608) 266-7320
Fax (608) 264-7751