In his Tuesday letter opposing the proposal to raise the weight limit for trucks from 80,000 to 91,000 pounds, D. Paul Sommerville quoted transportation engineers who said road degradation increases exponentially with increased vehicle weight (“Heavier trucks would dig deeper hole for S.C. roads”). That’s true only if the weight is not further spread out.
What he and other opponents seem to overlook is that these heavier trucks will have a seventh axle to spread out the weight. It’s not like an 18-wheeler overloaded by 11,000 lbs. These proposed 22-wheeler trucks will carry a lot more cargo, allowing for fewer trucks on the road. Truck drivers would be less overworked, and thus fewer of them would be falling asleep while driving.
Imagine the converse: The truck weight limit is cut in half. The resulting three-axle 10-wheelers would be able to carry half the cargo, and thus there would be twice as many trucks on the road. It would still add up to the same amount of weight.