WAUSAU, Wis. (WSAU) – State officials have released the results of what is literally a groundbreaking study on the impact of agriculture equipment on roads in Wisconsin.
A handful of Marathon County board members along with area farmers and manure haulers reviewed the results Thursday as discussions continue about how to solve the problem of overweight haulers on local roads.
The study's findings suggest that overweight vehicles may not cause as much damage as vehicles where the weight is spread on only a few axles.
“It was not the total weight of the vehicle, but the amount of weight on each axle,” said Kevin Erb, a conservation professional training coordinator for the University of Wisconsin Extension. “The more axles you have, the greater the spread of weight out.”
The Professional Nutrient Applicators Association of Wisconsin launched the four-year study with four state transportation departments, including Wisconsin. The study tested manure tankers with loads of 4,000 gallons up to 9,500 gallons. It also tested an 80,000 pound semi and a 102,000 pound semi. The 80,000 pound weight limit is federally mandated; anything heavier requires a special exemption.
The study revealed that the distance from a truck's tire to the edge of the pavement and how thick the pavement was factored into the amount of damage caused. In general, roads that were built with less asphalt and concrete suffered more damage than thicker roads. And, trucks caused more damage the closer they traveled to the edge of the road.
Erb said the study also found that trucks caused more damage in the afternoon than in the morning. But he said more research was needed to understand why.