Study: EPA-Certified Range Figures for EVs Unreliable

By Sean Tucker 04/24/2023 7:56am

Measuring the fuel economy and range of a gas-powered vehicle is, by now, a simple, solved engineering problem. Measuring the range of an electric vehicle (EV) is not. A new study suggests that the ranges and fuel economy equivalent figures published by the U.S. Environmental Protection Agency (EPA) are not particularly accurate.

Related: Electric Car Range – Everything You Need to Know

If the EPA’s numbers are off, we should note, then the rest of the world has it even worse. EPA range figures are famously lower than those published by many other governments.

SAE International, a global association of engineers and related technical experts in the aerospace, automotive, and commercial vehicle industries, used data from tests performed by Car and Driver to study real-world EV ranges.

In a 75 mph highway test, Car and Driver found that “more than 350 internal-combustion vehicles averaged 4.0 percent better fuel economy than what was stated on their labels. But the average range for an EV was 12.5 percent worse than the price sticker numbers.”

The discrepancy comes, in part, because of how the EPA calculates the numbers. In data it doesn’t publish, the agency calculates separate range figures for city and highway driving. It then publishes a combined range figure that assumes you’ll do 55% of your driving at more efficient city speeds. Those who drive on the highway more will achieve much lower range figures.

Other factors can cause misleading calculations as well. Extreme temperatures can drastically affect EV range – some EVs lose nearly a third of their range in the cold, others barely 3%.

In fairness, we should note that gas-powered cars also lose significant range in the cold. But the easy availability and speed of gasoline refills make this less of a factor in shoppers’ decisions.

Many manufacturers also suggest that owners never charge their batteries to 100% full to extend battery life. They may publish a range figure assuming a full battery, then use software to limit charging so that owners can’t easily fill the battery to full capacity.

The figures, SAE says, suggest a “need to re-evaluate the labeling procedures for this emerging technology as it continues to become increasingly prominent in the marketplace.”