Time to upgrade our thinking on highway risk before its too late

John Shutske
Proper marking and lighting of farm equipment helps motorists determine size of the equipment while improving overall visibility.

Just a few short years ago, Wisconsin upgraded laws for farmers who operate ag equipment on roadways—a set of requirements published by the state’s Department of Transportation that refer to these as implements of husbandry or “IoH.” The data on farm-related deaths in Wisconsin is disconcerting and suggests we maybe did not go far enough in modernizing our approach to roadway safety.

Officially published work by the National Farm Medicine Center and UW’s Center for Agricultural Safety and Health a couple years back documented that 17 people died between 2017 and 2018 because of roadway collisions involving farm equipment.

Preliminary data for 2019 to mid-2022 shows there were 36 farm-related incidents on Wisconsin roadways involving 60 different people injured, killed, or listed as “victims” on an incident database called “AgInjuryNews.”

Some of those affected by these incidents are farmers themselves, but many are non-farmer drivers and passengers impacted by this important public safety issue.

The state’s requirements for IoH apply to farm tractors, self-propelled machines like forage harvesters or combines, and a wide range of towed equipment like tillage implements, gravity flow wagons, manure spreaders, and forage boxes. Applying these laws can be complex and is dependent on factors like width and age of the machine. For example, newer federal regulations require more safety equipment for lighting and marking on farm equipment for machines manufactured in 2017 or after.

Passenger cars and trucks on the road are no match for farm vehicles and equipment in the event of a collision due to the sheer size and weight differences.

No match for farm equipment

The obvious danger is that these IoH machines are big, heavy, and slow relative to a car, pickup, motorcycle, or other motor vehicle traveling at posted speeds. As an example, the combination of a typical tractor pulling two 300-bushel gravity flow wagons can easily weigh 20 to 30 tons, while a passenger car or truck approaching from the rear will weigh one or two tons. The bestselling U.S. pickup truck weighs just under 6,000 pounds – a weight that is simply no match for most farm equipment if a collision happens.

MORE: Algoma man, 37, dies in crash with farm implement

If a motor vehicle is traveling at 55 miles per hour and the tractor/wagon combination at 15 mph, the approaching driver might as well be approaching a brick wall. If that tractor/wagon combination is making a left-hand turn and a driver decides to pass on the left because of a lack of turn signals or adequate marking, they, in fact, will be approaching something more damaging than a “brick wall.”

At a speed differential of 40 miles per hour (tractor going 15, car going 55), in just three seconds, the car will close on the IoH by more than half the length of a football field.  If the tractor is making a turn and is at a near standstill in terms of its forward movement and the motor vehicle driver is going 70 mph, that three-second delay means traveling GREATER than the length of a football field.

Even if the driver has a fast reaction time, they still need time to move their foot from the gas to the brake pedal. Then it takes time for the vehicle to slow down or to stop. Many motor vehicles have a 60 mph-to-zero braking distance that is between 100-150 feet.

Concerning bottom line

The bottom line—with human factors and simple physics at play, we should not be surprised that Wisconsin continues to see a very high rate of motor vehicle collisions, serious injuries, and deaths each year. The forces in play with an IoH and motor vehicle collision are devastating.

So, what do we do with this information? The upgraded Wisconsin state laws should be considered a baseline or an absolute bare minimum. Summary information can be found on the state DOT’s website at the link provided at the end of this article. Note that requirements for 2017 and newer machines are more stringent per federal requirements. Visit with your local equipment dealer to review your current situation and learn about opportunities to upgrade and improve your visibility.

There are a couple major differences between federal (2017 and beyond) and state requirements that are vital. Wisconsin state law does not require turn indicators on IoH vehicles, and amber flashers are only required on tractors and equipment wider than 12 feet or that extend over the center of a roadway.

The specifics of this requirement serve to exclude many common tractors found on Wisconsin farms from the “flashers” requirement as well as many tractor/implement combinations. Also, for equipment less than 12 feet wide, the use of lighting is only “required” in hours of darkness.

Life-saving considerations

As a farm safety specialist who has investigated hundreds of these tragic incidents over the past 35+ years in multiple states (and who grew up on a mid-sized family farm with older equipment, where we farmed across three different counties), here are a few recommendations.

  • If you operate on public roadways (almost all farms do!), you need to make yourself as visible as possible. I always tell farmers, “Light yourself up like a Christmas tree regardless state of federal regulation specifics!”
  • Make sure all lighting and marking (including SMV emblems) is clearly visible from the rear. Living in rural Dane County, I often come up on the back of a tractor and set of wagons or forage boxes in the fall. Often the tractor has all the needed lighting and marking, but sometimes that last hitched wagon does not. Or, another common site is a large manure wagon where nothing is visible from the backside simply because it’s blocked by caked-on manure.
  • Regardless of the lack of turn signal requirements in state law (remember, they are in fact required for 2017 and newer machines), turn indicators are crucial as safety equipment. If there are concerns about cost, age, and capacity of your tractor’s electrical system, etc., check with your dealer about LED lights that can be added to towed or mounted machines at a relatively low cost and easily moved from machine to machine.
  • For equipment under 12-feet in width, while state law says you only need lights activated “during hours of darkness,” that seems silly! If you have them USE THEM! Many highway collisions occur in normal daylight hours.

Finally, recognize that many farm safety issues and incidents would seem to be confined within the affected families when an injury or death occurs. People consider safety-related decisions to be a matter of personal freedom and responsibility. I actually see it a bit differently, as I’ve attended funerals and memorial services where a family member was killed in a farm “accident.” EVERYONE in the community is affected. The losses are forever.

That said, roadway safety is an issue that crosses into the public domain. I am concerned that if this issue is not taken more seriously that we will see actions that will be much more difficult to comply with or that might severely disadvantage key groups of ag producers in our state.

I also see the potential for individuals to be severely impacted economically because of not following some commonsense recommendations, especially when the technology is widely available to make yourself clearly seen when operating on public roadways. This is a common thread of lawsuits that I hear about on a weekly basis in my work. It’s wise for yourself, your family, and those in your local community.

Additional resources

  • Agricultural Vehicle Safety – Lighting and Marking Requirements for all IoH from Wisconsin State Department of Transportation:
  • Lighting and Marking of Agricultural Equipment on Highways Guide – Information that helps comply with federal laws and the National Agricultural Machinery Illumination Safety Act (AMISA) which impacts agricultural equipment produced new after June 22, 2017, is based: 
John Shutske is a professor of biological systems and engineering and is also an extension specialist at University of Wisconsin-Madison.

John Shutske is a professor and extension specialist with the UW-Madison Department of Biological Systems Engineering and UW-Madison Division of Extension, and director of the UW Center for Agricultural Safety and Health and can be reached at

Extension University of Wisconsin-Madison