Agricultural vehicle safety

IoH Lighting and Marking | Wide IoH Lighting and Marking | TraileringRules of the Road

Lighting and marking requirements for all IoH 

Wisconsin has lighting and marking requirements for all IoH. Self-propelled IoH and farm equipment exceeding 12 feet wide or that extend over the center of the roadway have specific lighting and marking requirements. This is to ensure the safety of IoH operators and the other traffic on the road.

All implements of husbandry shall have a slow-moving vehicle emblem mounted on the rear of the vehicle at all times. If a power unit's emblem is visible from the rear, any towed units are not required to have a slow-moving vehicle emblem.

During hours of darkness, all IoH must have the following lighting or marking. Lights or lamps must be activated when operating on the road or parked in the right-of-way:

 
​Self-propelled IoH and farm tractors
  • ​2 white headlights (Work lights are prohibited when vehicle is on the road or parked in the right-of-way.)
  • At least 1 red tail light. If purchased with 2 red tail lights, both must be working. Tail lights are to be mounted at a point within 20-72 inches off the ground.
  • Vehicles that are more than 4 feet wide to the left of the center line of the unit must have an amber reflector at the widest point on the left side, facing forward to warn on-coming traffic.
  • A slow-moving vehicle emblem, mounted on the rear and visible at all times.
​Towed IoH
  • ​2 red tail lights or 2 red reflectors on the rear.
  • Towed units that are 4 feet wide to the left of the center line of the towing unit must have an amber reflector at the widest point on the left side, facing forward to warn on-coming traffic.
  • A slow-moving vehicle emblem, visible to the rear at all times. A towed vehicle need not have a slow-moving vehicle emblem if the power unit vehicle's emblem is visible to the rear at all times.
​3-vehicle trains
  • ​1 red or amber light or 1 red or amber reflector must be located on each side of every vehicle in the train.
  • A slow-moving vehicle emblem, visible to the rear at all times. A towed vehicle need not have a slow-moving vehicle emblem if the power unit vehicle's emblem is visible to the rear at all times.
​Animal-drawn vehicle
  • ​1 white lamp visible from the front
  • 2 red lamps or lanterns or 2 red reflectors visible from the rear of the vehicle, marking the width of the vehicle, visible for 500 feet and mounted to indicate extreme width of the vehicle.
  • A slow-moving vehicle emblem, mounted on the rear and visible at all times. Religious exceptions apply.

Wide IoH lighting and marking requirements 

In addition to the requirements listed above for all IoH, self-propelled IoH that exceed 12 feet in total width and all "wide" IoH that exceed 15 feet in total width OR extend over the center of the roadway* are subject to specific lighting and marking requirements. Lights or lamps must be activated at all times, not just during hours of darkness.

*NOTE: Roadway widths vary. Standard lane width for county and state roadways marked with a center line is 11 feet. Therefore, an IoH in excess of 11 feet wide would be "wide." Some town roads are 18 feet wide, making an IoH wider than 9 feet subject to wide IoH lighting and marking requirements.

 

Self-propelled IoH and farm tractors wider than 12 feet​ 

  • All IoH lighting and marking requirements above.
  • ​A 360-degree yellow or amber rotating strobe or beacon light OR two flashing amber lights visible to the front and rear, mounted at the highest practicable point. 

Wide IoH- vehicles wider than 15 feet OR that extend over center of roadway

  • If a self-propelled vehicle, all IoH lighting and marking requirements above are required, including the 360-degree yellow or amber rotating strobe or beacon light or two flashing amber lights visible to the front and rear, mounted at the highest practicable point.
  • ​At least 2 amber flashing warning lamps, visible from both the front and rear. These lamps must be mounted to indicate the extreme width, as near as practicable but not more than 16 inches from lateral extremes.
  • At least 2 strips of yellow retroreflective material visible to the front. The outer edge of this material shall be mounted within 16 inches of extreme left and extreme right of vehicle.
  • Red retroreflective material, visible to the rear and mounted at the widest point practicable and within 25 inches of the extreme left and extreme right of the vehicle, spaced as evenly as practicable.
  • At least 2 red tail lamps mounted to the rear, or as close to the rear as practicable. These lamps need not be wired to light when headlamps or other lamps are activated; they can be battery powered.
IoH wider than 22 feet​
  • ​All Wide IoH lighting requirements above.
  • When traveling farther than .5 miles, an escort vehicle with hazard lights activated is required:
    • On a highway with one lane of traffic in each direction, the escort vehicle shall drive in front of the IoH.
    • On a highway with more than one lane of traffic in each direction or on a 3-lane highway, the escort vehicle shall drive behind the IoH.

Photos courtesy of Wisconsin Farm Bureau Federation

Trailering IoH

Provisions apply for IoH transported by trailer or semi-trailer to or from farm-related destinations. IoH of any width can be transported at times other than hours of darkness. Trailered IoH over 8.5 feet wide traveling on interstate highways must apply for an oversize permit from WisDOT.

Trailered IoH must have:

  • Yellow and red retroreflective tape
  • 2 flashing amber warning lights, visible to the front and rear, activated during trailering
  • A rear-mounted slow-moving vehicle emblem
  • For IoH wider than 12 feet, the amber strobe or beacon or the 2 flashing amber warning lights mentioned above must be activated. 

Legislative References: Chp. 347, Wis. Stat.

For more information on these requirements, visit UW Extension's Center for Agricultural Safety and Health's website.

Rules of the road

  • IoH must yield right of way to an oncoming vehicle and yield half of the roadway.
  • IoH may not drive on left side of roadway on a grade or curve or an area designated as no passing zone if it creates a hazard to oncoming traffic.
  • IoH may not drive so slowly as to impede the normal movement of traffic.
  • Must, if practicable, yield the roadway to an overtaking vehicle.
  • Motorists may not pass an IoH or Ag CMV in a no-passing zone.

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