Additional lighting and marking features are included for IOH that exceed 15 feet. There is no requirement for permitting based on a vehicle's width.
While operating on a highway, the following requirements apply:
IOH that exceed 15 feet or operate over the center line of the road when traveling will be required to add some lights and reflective material, if not already installed as original equipment
• Two flashing amber lights visible from the front and back placed 16 inches of the lateral extremities.
• On the back, red retro-reflective tape placed within 25 inches of the lateral extremities.
• On the front, two strips of yellow retro-reflective tape placed within 16 inches of the lateral extremities.
• Two red tail lamps (hard-wiring optional).
• A standard "slow-moving vehicle" (SMV) sign.
• During daylight hours, lighting requirements for IOH that exceed 15 feet or that operate over the center line of the road when traveling are not applicable if:
• The wide IOH is accompanied by an escort vehicle with hazard lights activated, and
• Two orange or red flags are attached to the rear of the IOH at the lateral extremities.
An IOH in excess of 22 feet, in addition to any lighting and/or marking required, must also be escorted by at least one vehicle with hazard lights activated.
• On two-lane roads the escort is the lead vehicle.
• On roads with two or more lanes with traffic going in the same direction, the escort vehicle is to follow the IOH.
• For "incidental movements" from farm to field or field to field under 0.5 miles, no escort is required.
• For an IOH operated or transported to or from an implement dealer for purposes of delivery, repair or servicing within a 75-mile radius, requirements for lighting, marking, and escort vehicles noted above apply.