It’s an all-too-familiar scene along the two-lane roads that crisscross farm country: A tractor drives slowly ahead, often at this time of year pulling a grain cart loaded with corn or soybeans. A car driver not familiar with such vehicles approaches too quickly from behind and, unable to stop in time or trying to pass in unsafe conditions, loses control and crashes.

A new study by the University of Iowa College of Public Health estimates that more than half the 7,083 accidents involving farm vehicles in Minnesota and eight other states between 2005 and 2010 could have been prevented if state policies required more lighting and reflection on the farm equipment.

Marizen Ramirez, University of Iowa professor of occupational and environmental health and lead author of the study, said the likelihood of crashes is greater during crop harvest in October and November, when more farm vehicles are on the roads and the sun rises later and sets earlier.

“Most of these crashes occur because of the farm equipment being rear-ended or sideswiped by a passenger vehicle that’s not aware of the size differential or the speed differential,” she said. “Even traveling right outside the Twin Cities, you’re bound to run into some farm equipment.”

The farm vehicles might also include combines, sprayers and tilling equipment or other implements pulled by tractors.

The ag equipment is not covered under the federal motor vehicle code, so it’s left to states to determine what their policies will be for lighting and marking, said Ramirez, who moved recently to a new job at the University of Minnesota.

The researchers found lower crash rates in states with more stringent lighting and marking policies.

The American Society of Agricultural and Biological Engineers (ASABE) has issued guidelines on lighting and marking farm vehicles to promote safety among all roadway users. The recommendations suggest certain numbers of headlights, taillights and turn signals, and specifies the location of lights as well as the number and size of reflective markers and slow-moving vehicle emblems.

Ramirez said the guidelines are the “gold standard” for safety, and the study used them to compare and score each state based on how many of the practices were required. On a scale of 100, the states ranged from a low of 12 in Missouri to a high of 69 in Illinois. Minnesota ranked in the middle of the pack with a score of 45.

The average number of motor vehicle crashes involving farm equipment in each state could be reduced by more than half if additional lighting and marking was required and installed, Ramirez said.

The study was published in the September issue of Occupational and Environmental Medicine, an international journal.

Bruce Gordon, communications director for the Minnesota Department of Public Safety, said Minnesota has not enacted any new laws regarding lighting and marking of farm vehicles in the years since the 2006-10 study period.

The state’s most recent motor vehicle crash data showed that 132 farm and passenger vehicles were involved in crashes with each other in 2015, including 48 in accidents that caused injuries.

Farm vehicle crashes on public roads have also resulted in about two fatalities each year since 2010, according to state records, and five that occurred in 2013.

Ramirez said that the study looked only at state policies and crash data, and did not attempt to gauge whether farmers had installed more or less lighting and signage on vehicles than their states require.

Many farmers use older equipment, she said, so the next stage of research will be to understand how those machines are lit and marked. The researchers are working with the U.S. Department of Agriculture to survey farmers across the nine states to ask about tractors used most frequently on the road and how they are lit and marked.

Researchers have also developed lighting and marking kits, Ramirez said, and have tried to promote safety by distributing them at farm shows and other events. The intent, she said, is not to blame farmers but to reduce potential accidents.

“It’s the other vehicles that are involved in causing many of these crashes,” she said. “We’re sharing the roadways, and everybody playing their part can really make them safer for everyone.”