New Research Asks What Speeding In The United States Actually Costs (Hint: Millions In Fuel, Thousands of Deaths, With Just 54 Seconds Saved)

If you speed to save time, a new study has calculated exactly how much time you are saving. It is not much, and the costs are considerably larger.

A new peer-reviewed study published in Nature portfolio journal Communications Sustainability has now put precise numbers on just how unfavorable it is. Researchers at the University of Minnesota analyzed more than 120 million vehicle trajectories spanning every season in the United States. Using physics-based energy consumption models matched to real vehicle classes and real driving conditions, they calculated what would happen if American drivers simply followed posted speed limits on highways and arterial roads. Here are the striking and sobering findings:

• If drivers adhered to speed limits, the study estimates, the United States could save more than 6 million gallons of fuel, avoid more than 50,000 metric tons of carbon dioxide emissions, and retain more than $18 million in daily fuel costs.
• On an annual basis, those savings would be comparable to removing approximately 5.5 million conventional passenger vehicles from the road entirely.
• The time cost of driving at the speed limit: an average of 54 seconds per day.

“We see the consequences of speeding every single day, and none of them are about saving time,” said Matt Clark, attorney and managing partner at the Law Office of Chain | Cohn | Clark. “They are about life-altering crashes. This study puts a number on what speeding costs in fuel and emissions. The human cost does not fit in a spreadsheet.”

The Fuel Problem

The University of Minnesota study defines speeding as any instance where a vehicle exceeds the posted speed limit by any positive margin on highways and arterial roads with speed limits of at least 45 miles per hour. Under that definition, 43% of trips in the dataset contained at least one speeding event. Among trips where speeding occurred, drivers spent an average of 12% of their trip time above the limit, with a mean maximum speed excess of 11 miles per hour.

The physics underlying the fuel cost is straightforward. Aerodynamic drag increases with the square of speed, meaning that the faster a vehicle travels, the disproportionately more energy it consumes. For light-duty vehicles, fuel economy is optimized somewhere between 40 and 55 miles per hour. Raising highway speed limits from 55 to 70 miles per hour, which occurred across much of the United States in the decades following the 1970s, increased fuel consumption by up to 38%, according to prior research cited in the study. Even a modest 10 miles per hour increase in cruising speed over the limit can raise fuel consumption and carbon dioxide emissions by up to 21% .

Those percentages, applied across a national fleet of hundreds of millions of vehicle trips per day, produce the study’s headline numbers. Speeding is not a minor inefficiency at the margins of American fuel consumption. It is a measurable, quantifiable, and avoidable drain on both household budgets and national energy resources.

California’s Role

The study examined battery electric vehicles separately within California, the only state with a sufficiently large electric vehicle share to support meaningful analysis. Among California EV trips, 37% contained at least one speeding event, compared to 44% of comparable conventional vehicle trips in the state. Electric vehicles showed higher percentage energy savings from speed limit adherence than conventional vehicles, reflecting the efficiency characteristics of electric powertrains and the mitigating effect of regenerative braking.

For California drivers, whether in conventional vehicles or EVs, the study’s findings are directly applicable. The state’s major highway corridors, including Interstate 5, Interstate 80, Highway 99, and Highway 58, all running through or near Kern County, are precisely the types of limited-access, high-speed roads where the study’s energy savings calculations apply most strongly. These are also, not coincidentally, the corridors where serious and fatal crashes are concentrated.

The study notes that its analysis is conservative, covering only highways and arterial roads with speed limits of at least 45 miles per hour and excluding lower-speed roads entirely. True nationwide speeding prevalence, and the associated fuel, emissions, and safety costs, is likely higher than the study documents.

The Time-Saving Myth

Perhaps the most consequential finding in the study is its direct quantification of the time-saving argument for speeding. Drivers who exceed the speed limit frequently report that they do so because they are in a hurry, and that the speed limit simply does not reflect how fast it is reasonable to travel on a given road.

The study tests that premise with data. Consistent speed limit adherence on highways and arterial roads results in a travel time increase of approximately 190 seconds per 100 vehicle miles traveled, which translates to about 54 seconds per average daily driving day, or 6 minutes per week. A 2015 naturalistic driving study from Australia cited in the research found comparable results, with individual drivers saving an average of 26 seconds per day and 3 minutes per week by speeding.

The researchers are direct in their conclusion: “Our results reinforce the notion that the ‘speeding to save time’ paradigm is largely illusory and offers no meaningful benefit to everyday drivers.”

That conclusion carries particular weight when placed alongside the safety data. In 2023, according to federal statistics cited in the study, 11,775 fatalities in the United States were associated with speeding-related crashes. The study notes that while eliminating speeding would not prevent all such fatalities, even modest reductions in speeding prevalence could yield meaningful safety benefits. Against a backdrop of nearly 12,000 deaths per year and tens of millions of dollars in daily fuel waste, the 54-second daily time cost of driving the speed limit is a remarkably small number.

What This Means for Crash Cases

For individuals and families affected by crashes involving speeding drivers, the legal framework surrounding speed-related negligence is well established in California. Drivers are required by law to operate their vehicles at safe speeds given road conditions, and exceeding the posted speed limit is a violation of that duty. When speeding contributes to a crash that injures or kills someone, it is a central element of the liability analysis.

The study’s findings are relevant to that analysis in several ways. The research documents that speeding is not primarily driven by road conditions or traffic emergencies but by driver choice, and that the choice produces negligible time savings while generating substantial additional risk. Speeding drivers going 10 or more miles per hour over the limit face significantly increased stopping distances, reduced reaction time, and dramatically amplified crash forces. The physics are unforgiving: speed increases crash severity in ways that are not linear.

In serious injury and wrongful death cases, establishing how fast a vehicle was traveling at the time of impact is often a critical component of the case. Evidence sources include event data recorders embedded in modern vehicles, telematics data from insurance-based monitoring programs, traffic camera footage, physical evidence at the scene, and in some cases witness accounts of vehicle speed in the moments before impact. Securing that evidence quickly, before vehicles are repaired, data is overwritten, or witnesses become difficult to locate, is essential.

The legal significance of speeding extends beyond the immediate liability question. In California, the degree of a defendant’s negligence is relevant to the full scope of damages a plaintiff may recover. A driver who was traveling 20 miles per hour over the speed limit presents a different legal picture than one who was marginally over the limit. The combination of speeding with other risky behaviors, such as cellphone use, which a separate 2026 IIHS study found increases significantly alongside speeding magnitude, can further shape the damages analysis.

“When we take on a crash case, one of the first things we want to know is how fast the driver was going, not just because it establishes what the law says they did wrong, but because it tells us something about the nature of the choice they made,” Clark said. “A driver going 85 miles per hour on a 65-mile-per-hour highway did not make an error in judgment. They made a decision, and this research makes clear it was a decision that saved them less than a minute while putting everyone around them at serious risk.”

A Different Way to Think About the Road

The University of Minnesota study frames its findings primarily in terms of energy, economics, and emissions. Its core message, that the costs of speeding are large and the benefits negligible, applies equally to the safety dimension that sits alongside those environmental and economic calculations.

The 54-second figure is a useful lens. Fifty-four seconds is how much time the average American driver would add to their daily driving by following speed limits on highways and arterial roads. It is less time than most people spend waiting for a traffic light or finding a parking space. It is a small fraction of the time spent at a red light, in a drive-through, or in any of the dozens of minor delays that define a typical commute.

Against that 54-second figure sit the study’s documented costs:

• 6 million gallons of fuel
• $18 million
• 50,000 metric tons of carbon dioxide
• 11,775 Americans who died in speeding-related crashes in 2023 alone.

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If you or someone you know is injured in an accident at the fault of someone else, or injured on the job no matter whose fault it is, contact the attorneys at Chain | Cohn | Clark by calling (661) 323-4000, or fill out a free consultation form, text, or chat with us at chainlaw.com.