A new study from the University of Minnesota Twin Cities, published in the journal Communications Sustainability, has quantified the benefits of simply obeying posted speed limits. Analysing over 120 million real-world vehicle trips in the United States, researchers found that nationwide compliance could save approximately $22 million (€19.26 million), more than 25 million litres of fuel, and 57,000 tonnes of carbon dioxide every single day.
While the study focuses on US data, the implications for Europe are clear. According to the EU-supported Odyssee-Mure project, light-duty vehicles (LDVs) — cars and small vans — account for about half of the energy consumed in European road transport. These vehicles also represent 14.6 per cent of total energy consumption in the US, underscoring the potential for similar savings across the Atlantic.
Minimal Time Cost, Maximum Gain
The research found that sticking to the speed limit added less than 54 seconds to the average daily commute. “While internal combustion engine-powered vehicles have become significantly more efficient in the past decades, they have also become much more powerful,” said William Northrop, a mechanical engineering professor at the University of Minnesota and corresponding author of the paper. “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.”
The savings could increase further if fuel prices rise, a scenario that remains plausible given ongoing geopolitical tensions. The researchers plan to expand their framework to include more diverse roadways and to study the impact of “aggressive accelerations” on fuel use and emissions. “Exploring both speed and acceleration reductions will give us an even more complete picture of real-world fuel savings potential,” Northrop added.
For European drivers, the financial and environmental stakes are high. In the UK, the Energy Saving Trust estimates that a full charge for an electric vehicle (EV) costs about £17 (€19.91) and provides a range of around 220 miles (354 km). Driving a petrol or diesel car the same distance costs more than double, at £45 (€52.69). EVs also produce zero tailpipe emissions, with energy giant EDF calculating they emit just 50 grams of CO2 per kilometre on average, compared to 165 grams for petrol and 170 grams for diesel cars. However, EV production, particularly lithium-ion battery manufacturing, generates higher emissions than conventional cars.
Meanwhile, the shift toward electric mobility is accelerating across Europe. New battery-electric vehicle (BEV) registrations in the EU rose 48.9 per cent in March compared to the same period last year, according to the European Automobile Manufacturers’ Association (ACEA). BEVs now hold a 19.4 per cent market share for the first quarter of 2025, up from 15.2 per cent in the same period of 2024. Italy led the surge with a 65.7 per cent increase in BEV registrations, followed by France and Germany. Hybrid-electric vehicles (HEVs) still dominate with a 38.6 per cent share, while petrol and diesel registrations continue to decline, dropping to 28.7 per cent and 7.7 per cent respectively.
The broader context of energy and environmental policy in Europe also includes challenges such as heat-driven droughts and the need for sustainable transport solutions. As the continent pushes toward its climate goals, even small behavioural changes like driving at the speed limit can contribute meaningfully to reducing emissions and saving money.
