Tuesday, August 28, 2007

The Bridge Collapse and Implications for Farm Traffic

The Minnesota I-35W bridge collapse brought national attention to America's aging infrastructure. Recent news articles are filled with statistics meant to strike fear into the heart of the American driver. After reading only two post-bridge collapse articles I learned how many high traffic bridges in the U.S. are over the age of 60 (322), how many bridges have a design remarkably similar to the I-35 collapsed bridge (765) and the grade the American Society of Civil Engineers gave American infrastructure (a D).

This flurry of statistics portends political attention and maybe some change. In Minnesota, farmers may feel some of the political fallout. Farmers are the only class of drivers exempt from size and weight restrictions on Minnesota roads, and pretty much every other state. Currently, farmers hauling grain or manure can load up vehicles to their heart's delight. No big deal, except that fully loaded grain carts can weigh upwards of 100,000 lbs. Compare to a fully loaded semi, which legally cannot weigh more than 80,000 lbs under federal highway standards.

A fully loaded farm vehicle damages the roadways more than a semi because grain carts and manure spreaders often distribute their weight over only 3 axles and sometimes only 1. Semis, on the other hand, distribute their load over a bevy of double axles. Engineers design American bridges and roads with semis in mind, not grain carts.

It's hard to say if farm vehicle traffic really does damage roadways. The Minnesota Farm Bureau claims that farmers drive heavy vehicles over roadways too infrequently to damage roads. Others disagree. For the second time, the Minnesota Association of County Engineers is lobbying for legislation to eliminate the farm exemption. They claim that farm vehicles and loads have grown since the passage of the law 14 years ago. The engineering view already won the day in Iowa. In 1999 the Iowa legislature passed a bill forcing all farm vehicles to comply with weight limits, including single axle weigh limits. Iowa farmers can apply for an 8 week permit to drive oversize loads, but farmers must pay for any they passage causes to bridges.

Farmer groups maintain that farmers do not take advantage of the weight exemption very often, but want the law to stay the same. Minnesota Farm Bureau indicated that farmers hardly ever drive fully loaded grain carts and the Minnesota Pork Producers Association claims that most farmers use semis to transport manure. Hmm. If the farm groups want to keep the law as is, maybe farmers use the exemption more than they want to let on.

After thinking about this overnight, I would guess that the proposed change probably does not matter much for farmers. The new law would probably mean two trips to the grain silo, rather than one. I called the Iowa Farm Bureau to see if anyone was available to gripe about Iowa's weight restrictions. No one seemed to care or even remember the not-too-distant past when Iowans could freely travel with fully loaded manure spreaders. This reaffirms my guess that the proposed Minnesota law will not devastate the farm community.