Asphalt: Smoothness Matters
Did you ever consider that smoothness of asphalt has an effect on vehicle fuel economy?
Studies have shown, the smoother the pavement, the lower a vehicle’s fuel consumption. In addition to all of the technology used by automakers to improve fuel consumption, state transportation agencies are now looking at additional ways to reduce emissions. Pavement smoothness has been a hot topic within this issue; with tire-pavement rolling resistance, pavement stiffness, and pavement smoothness being heavily studied.
Rolling Resistance is the loss of a vehicle’s energy due to contact between the tires and the pavement. A failing pavement will create a greater friction, whereas a newer smoother pavement will increase fuel economy.
The pavement’s stiffness is an indicator of strength and accounts for 0.005 to 0.5% difference in fuel consumption, depending on the type of vehicle. These low estimates are based on theoretical calculations and have a minimal effect on vehicle fuel consumption.
Pavement smoothness affects rolling resistance by influencing friction between the tire and the pavement. A field study was conducted by the Federal Highway Administration at the WesTrack pavement test track in Nevada. The results of this study revealed that trucks running on slightly smoother pavement could reduce fuel consumption by 4.5%. Other studies conducted using cars on smoother pavements have shown similar or greater fuel savings. When the roughest pavements in a highway network are compared to the smoothest, the fuel savings are even greater. Some experts believe that rehabilitating the roughest pavements will reduce fuel consumption by up to 10%.
In addition to smoother pavements reducing fuel consumption, it has also been proven to reduce vehicle operating costs and driver fatigue by minimizing tire bounce and load impacts. Driving on rough roads costs our nation approximately $65 billion annually in extra vehicle operating costs, per The Road Information Program (TRIP).
Truck tires roll along smoother pavement causing it to last longer; as opposed to bouncing on bumps, causing the rate of road deterioration to accelerate. Studies have shown that improving pavement smoothness by 25% results in almost a 10% increase in pavement longevity. With longer lasting pavement, we conserve natural resources while saving our taxpayers money.
For all these reasons, smoothness matters when it comes to asphalt pavement.
Crisdel Group, Inc. is known for constructing some of the smoothest roads, but don’t just take our word for it, check out some of our award-winning projects on our website: http://www.crisdel.com/projects