A Smoother Road Could Lead to Energy Savings and Increased Safety
This guest post is provided by Andrew Johnson, former employee of the UDOT Traffic Operations Center.
The rising gas prices have had an effect on all of us, one way or another, and without any relief in sight, many of us are looking for ways to save money and improve fuel efficiency. When we think about ways to improve mileage and save money, the factors that usually come to mind involve aerodynamics, engine efficiency, and tire pressure, but recent studies suggest that there is at least one external element that could impact both safety and energy savings.
Dr. Richard Willis, an assistant research professor at Auburn University, reported that some simple improvements to the smoothness of road pavement could save a lot of money. He suggests that, in total, we could save 2.4 billion gallons of gasoline and 900 million gallons of diesel every year, which would lead to an estimated $12.5 billion.
The problem is from something called rolling resistance, which can be defined as the energy that is lost between the tire and road. The imperfections in the pavement, as well as the stiffness of the tires, directly affects how energy is lost and how much is required to keep the vehicle in motion. Of course, it shouldn’t come as a real surprise that the less time we spend bouncing around on roads and highways, the more efficiently our vehicles will run.
Understanding the Numbers
The numbers for the above study were broken down like this: In 2010 a study by Schmidt and Ullidtz showed that slight improvements in road smoothness could yield reductions in fuel consumption by 1.8 to 2.7%. Some other studies have actually suggested that this number could be much higher – as much as 4.5%. The Bureau of Transportation Statistics, on the other hand, says that vehicles consumed 168 billion gallons of gasoline and diesel, which means that at an average price (according to AAA) of $3.66 per gallon ($3.93 for diesel) and a conservative estimate of 2% fuel reduction, we arrive at the $12.5 billion figure.
The National Highway Traffic Safety Administration says that one third of all highway fatalities can be attributed to poor road conditions. Perhaps a little surprising is that most of these fatalities happen on two-lane, while the highways are comparatively safe. The combination of better road quality and better conditions (better visibility, wider lanes, etc.), actually seems to be more conducive to safe driving.
Utah’s Road Conditions
So how well has Utah done with providing smooth roads? According to the Federal Highway Administration – pretty good. The FHA released some statistics in 2008 that put Utah near the top for maintaining good roads. Of Utah’s roads, only 6.4% were considered to be in poor or mediocre condition, which is pretty good compared to states like New Jersey or Hawaii (48.6% and 44.4% of their roads, respectively, were considered to be in poor or mediocre shape).
More and more studies are showing us exactly how important it is to maintain our roads and look for ways to improve driving conditions. While there is a lot of internal factors that affect driver safety and energy usage (from engine efficiency to simply being a conscientious driver), a smoother road can have more impact than many of us think.
American Road and Transportation Builders Association, FAQs
National Asphalt Pavement Association, Press Release