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.