Every driver has told themselves the same lie at least once: going a few miles over the limit will get you there noticeably faster. A new University of Minnesota study says that's mostly wishful thinking. Researchers analyzed 120 million real-world trips across U.S. road networks, factoring in speed limits and elevation data, and found that obeying the posted limit costs drivers less than a minute of extra travel time on average.
The upside of slowing down, according to the study, is bigger than the time cost suggests. If American drivers stuck to posted speed limits, the researchers estimate the country could save $22 million and 6.7 million gallons of gasoline a year, while cutting carbon dioxide emissions by roughly 57,000 metric tons daily.
The paper, published in the peer-reviewed journal Communications Sustainability, was led by William Northrop, a University of Minnesota mechanical engineering professor and the study's corresponding author. "Driving fast is easier than ever. Our study examines an obvious yet difficult-to-implement intervention for major fuel savings that can be achieved without replacing our cars: driving slower," Northrop said. Co-author Bharat Jayaprakash added that quantifying the exact scale of those savings nationally "gives us a clearer picture of the actual impact."
The study focused on light-duty, engine-powered vehicles, which account for about 14.6% of total U.S. energy consumption. Researchers say next steps include testing instrumented electric vehicles to see how aggressive acceleration, not just top speed, affects fuel use and emissions.
The findings arrived via AP News and quickly circulated through Fox affiliates and other outlets nationwide.