Folks around here are quick to single out Michigan's heaviest-in-the-nation truck limits for the state's battered pavement.
Problem is, officials in and out of the trucking and road industries tell me there's no conclusive evidence that lowering weights would make much of a difference.
They say Michigan's major roads are built to handle heavier loads than other states, and weather and chronic underfunding of roadwork are bigger reasons behind our poor roads.
I wrote recently about efforts to raise the state's gas tax by up to 9 cents a gallon and heard from dozens of readers who said they'd grudgingly consider paying more -- but only if Michigan would ban 82-ton monster big rigs.
"Michigan has a limit that is double the national average and you can see the damage everywhere as you travel our expressways," reader Gene Hall of Allen Park wrote in an e-mail. "Taxpayers could save billions if Michigan fell in line with the other states."
An independent expert who has looked at the issue disagrees.
"You can't just say Michigan's roads are breaking up just because the difference here is trucks, because you have a lot of other powerful forces at work here," including the state's intense freeze-thaw cycles and its long history of inadequate road funding, said Steve Karamihas, a senior research associate at the University of Michigan Transportation Research Institute.
His expertise includes vehicle dynamics, road roughness and other pavement issues.
No one argues that big rigs aren't a significant cause of road deterioration. Trucks in general cause more damage than passenger vehicles.
But singling out the super-heavy trucks is disingenuous because:
• Of the roughly 130,000 big rigs registered in Michigan, only about 600 to 900 trucks in any given year are licensed to carry the heaviest loads, up to 164,000 pounds, according to the Michigan Trucking Association. That's less than 1% of trucks registered in Michigan.
• The Michigan Department of Transportation said less than 5% of all big trucks in Michigan carry less than the maximum but more than 80,000 pounds, which is the limit in many other states.
• Michigan requires heavier trucks to distribute their weight over more axles to spread the weight over more pavement area. Trucks on Michigan roads carry 13,000 to 16,000 pounds per axle, while the average in other states is 17,000 to 20,000, MDOT said.
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Problem is, officials in and out of the trucking and road industries tell me there's no conclusive evidence that lowering weights would make much of a difference.
They say Michigan's major roads are built to handle heavier loads than other states, and weather and chronic underfunding of roadwork are bigger reasons behind our poor roads.
I wrote recently about efforts to raise the state's gas tax by up to 9 cents a gallon and heard from dozens of readers who said they'd grudgingly consider paying more -- but only if Michigan would ban 82-ton monster big rigs.
"Michigan has a limit that is double the national average and you can see the damage everywhere as you travel our expressways," reader Gene Hall of Allen Park wrote in an e-mail. "Taxpayers could save billions if Michigan fell in line with the other states."
An independent expert who has looked at the issue disagrees.
"You can't just say Michigan's roads are breaking up just because the difference here is trucks, because you have a lot of other powerful forces at work here," including the state's intense freeze-thaw cycles and its long history of inadequate road funding, said Steve Karamihas, a senior research associate at the University of Michigan Transportation Research Institute.
His expertise includes vehicle dynamics, road roughness and other pavement issues.
No one argues that big rigs aren't a significant cause of road deterioration. Trucks in general cause more damage than passenger vehicles.
But singling out the super-heavy trucks is disingenuous because:
• Of the roughly 130,000 big rigs registered in Michigan, only about 600 to 900 trucks in any given year are licensed to carry the heaviest loads, up to 164,000 pounds, according to the Michigan Trucking Association. That's less than 1% of trucks registered in Michigan.
• The Michigan Department of Transportation said less than 5% of all big trucks in Michigan carry less than the maximum but more than 80,000 pounds, which is the limit in many other states.
• Michigan requires heavier trucks to distribute their weight over more axles to spread the weight over more pavement area. Trucks on Michigan roads carry 13,000 to 16,000 pounds per axle, while the average in other states is 17,000 to 20,000, MDOT said.
more
