New research shows that fixing roads is a great way to tackle climate change.
By Marlene Cimons
With Democrats in control of the House of Representatives and Republicans in control of the Senate, Congress is unlikely to produce any significant legislation on divisive issues like climate change. However, lawmakers may tackle the carbon crisis by other means, including through legislation on infrastructure, one possible area of compromise.
Even if Congress fails to invest in solar energy or EV charging stations, just renovating America’s streets, highways and freeways will reduce pollution. Road repairs help drivers use less gas, reducing carbon pollution, according to a new study published in the International Journal of Sustainable Transportation. Though steamrollers and other machines generate pollution while fixing roads, filling cracks and potholes does more to limit emissions overall.
“There are many ways to combat climate change from the transportation side, from the design and maintenance of roads to the utilization of renewable or clean energy for vehicles,” said Hao Wang, an associate professor in the department of civil and environmental engineering at Rutgers University and lead author of the study. He explained that filling potholes and smoothing roads helps drivers use less gas.
Cracks and bumps in the road slow cars, while wearing down tires, shock absorbers and suspensions. Drivers have to burn more gas and produce more carbon pollution to go the same distance. Crumbling streets and highways are a big problem in the United States. In 2017, the American Society of Civil Engineers gave the country’s roads a D. The sorry state of U.S. infrastructure is worsening emissions from the transportation sector, which accounts for nearly one-third of all U.S. carbon pollution, according to the Environmental Protection Agency.
The scientists, who also included researchers at North Dakota State University and Al-Mustansiriyah University in Iraq, found maintaining roads could reduce driving-related greenhouse has emissions by up to 2 percent. This could also help transportation agencies cut the cost of roadway repair by up to 30 percent. And drivers can benefit too. Well-maintained roads can cut money spent on fuel and car repairs by up to 5 percent.
Governments can save money by continuously maintaining roads rather than addressing cracks and potholes after they become a big problem. This can also help drivers use less fuel. Scientists came to this conclusion after studying data from the Federal Highway Administration’s Long-Term Pavement Performance program as well as data from the Motor Vehicle Emission Simulator developed by the EPA to assess the environmental impact of roadway repairs.
The study looked at the carbon footprint of common methods of preserving pavement, such as overlaying roads with liquid asphalt, spreading a mix of asphalt and crushed rocks over roads, and filling cracks in the road with rubberized asphalt. The study found that covering roads with liquid asphalt, what’s known as a “thin overlay,” produces the largest reduction in carbon pollution by doing the most to smooth the road.
“The good timing of applying thin overlays depends on the road condition, not just the age of the road,” Wang said. “Traffic and climate play important roles here. The roads with heavier trucks and very hot or cold climates deteriorate faster and should be repaired earlier.”
As a researcher in the field of transportation infrastructure, Wang said he was constantly seeking ways to keep the roads in good condition and help drivers conserve fuel. “Recently, pavement preservation — or preventive maintenance — has been used by highway agencies to extend pavement life, but little research has looked at its impact on the environment,” he said.
Wang’s interest in roads is not purely altruistic. “Of course, I always feel more motivated to continue my research when I drive on the roads with cracks or potholes,” he said.