SMOOTHNESS
When traveling on smooth pavements, truck tires don't bounce!
Truck tires rolling along on smooth asphalt pavement don't deliver the kind of impact loading they would on a rougher pavement. Some experts estimate that a 25% increase in smoothness yields a 9% to 10% increase in the life of a pavement. So, not only are smooth pavements more comfortable, they also are more economical.
http://www.asphaltroads.org/why-asphalt/engineering/smoothness/