Pavement Preservation Journal, Winter 2011, Vol. 5, No. 2
A new study shows that one road to energy savings could already be under the wheels of our cars: smoother pavements, reports the National Asphalt Pavement Association.
Dr. Richard Willis, an assistant research professor at Auburn University, reported in July that modest improvements in the smoothness of pavements could save up to 3.7 billion gallons of gasoline and 1.3 billion gallons of diesel for the U.S. every year, a total of 5 billion gallons of fuel for the vehicles being driven on our highways. In other terms, smoothing out America’s roads and highways could save around $12.5 billion a year for the U.S. economy.
Willis and Auburn’s Dr. Rob Jackson completed an analysis of more than 20 studies from throughout the world. At NAPA’s midyear meeting Willis presented a preview of a study that will be published soon by Auburn. He reported that smoothness is a pavement characteristic that has one of the greatest impacts on fuel economy.
“We know that, of all the factors that influence fuel economy — vehicle aerodynamics, engine dynamics, ambient air temperature, tire geometry, vehicle speed, tire pressure, and so forth — there is only one that pavements can affect, and that is rolling resistance,” said Willis. “Rolling resistance can be thought of as the force required to keep tires rolling. It could also be thought of as the energy lost between the vehicle and the pavement. Of the two
main influences on rolling resistance related to pavements — those due to the stiffness properties off the tire
and those due to imperfections in the pavement surface — the pavement industry has the opportunity to influence only one, the pavement itself.”
NAPA president Mike Acott pointed out that rough roads cost Americans billions for excess repairs. “TRIP, The Road Information Program, calculates that rough roads cost the average American motorist $324 every year, a total of $67 billion, just for extra wear and tear on vehicles,” Acott said. “Adding this figure to the $12.5 billion in potential fuel savings, we can see that the U.S. could save nearly $80 billion a year by building and maintaining smoother pavements.”