Research: Driving too fast consumes a lot of fuel but saves little time

A study published this week in the scientific journal Nature Communications Sustainability reveals that speeding does little to save time while significantly increasing fuel consumption and harmful emissions. According to data analyzed from 2021, which included over 120 million trips in the United States, primarily on roads with speed limits of 72 kilometers per hour or higher—43 percent of these journeys involved at least one instance of speeding. Drivers spent nearly 12 percent of their driving time exceeding legal speed limits, according to reports cited by Associated Press (AP). The findings challenge common perceptions that faster speeds equate to greater efficiency. The research conducted by scientists at the University of Minnesota suggests that drivers of internal combustion engine vehicles could save approximately $22 million daily, around €19.2 million, if they adhered strictly to speed limits. This would translate into roughly 25.4 million liters of fuel saved each day and prevent the release of about 57,000 tons of carbon dioxide annually. The researchers compare this impact to removing around five million personal cars from the road. These figures highlight the substantial environmental and economic benefits of maintaining safe speeds. When considering today’s average fuel prices and increased annual mileage, Americans could potentially save about $26 million, approximately €22.7 million, and around 27.3 million liters of fuel per day by avoiding unnecessary acceleration. However, the study also underscores that even with these savings, the time gained through speeding is minimal. On average, driving within speed limit or slightly slower than allowed extends travel time by just 54 seconds per day for a typical daily journey of 46 kilometers. William Northrop, a professor of mechanical engineering at the University of Minnesota and co-author of the study, told AP that many drivers believe faster driving saves valuable time. “If your goal is to save one minute, you have to drive fast,” he explained. “But if you want to arrive safely and save fuel, you might decide to drive a bit slower than the posted limit.” His comments reflect the nuanced trade-offs between speed, safety, and sustainability. The study also found that slower driving can benefit electric vehicles. Based on modeling for California, the only state consistently included in the analysis of electric vehicle usage, the researchers concluded that reducing speed has positive implications for energy efficiency and battery longevity. This finding adds another layer to the argument for responsible driving practices, particularly in regions with high adoption rates of electric transportation. The research was based on extensive data collection and simulation models, ensuring its conclusions are grounded in empirical evidence rather than anecdotal claims. While some drivers may feel that speeding allows them to complete tasks more quickly, the study demonstrates that such perceived gains come at a considerable cost. By contrast, adopting a more measured approach to driving offers tangible benefits in terms of both resource conservation and long-term environmental health. As the world continues to grapple with rising fuel costs and climate change, the findings serve as a clear call for reconsidering how we navigate our roads.