EPA Downplays Hybrid MPG by 33 Percent, Study Claims

One of the jobs the EPA has to do is the collection of fuel economy and related emissions data that are passed on to a number of federal programs like the Fuel Economy and Environment Label required on all new cars.
Toyota Camry 1 photo
Photo: Toyota
Well, according to a new study reported in the ACS journal Environmental Science & Technology and cited by Green Car Congress, EPA's ratings are not always spot on.

The study found out that when including real-world road grade and ambient conditions compared to controlled laboratory tests, fuel consumption ratings for a hybrid electric vehicle increased by 18% highway and 33% city compared to estimates based on EPA adjusted fuel economy “sticker” values.

The experiment

According to the same source, University of Vermont researchers Britt A. Holmén and Karen M. Sentoff carried on the experiment and in doing so, they used two 2010 Toyota Camry models: one hybrid and powered by a traditional ICE (internal combustion engine).

What they did was take the two cars on a 32-mile real-world course, a totally opposite environment compared to EPA's controlled lab settings.

What you need to know is the EPA-rating on the hybrid Camry used as one of the test cars: 33 mpg in the city and 34 mpg on the highway. After being taken around the special course and measurements were done, the results were as follows: fuel economy improved to 44 mpg city and 40 mpg highway.

“Our real-world … measurements suggest computed city cycle [conventional vehicle] fuel use would be nearly 2 times higher than for the [hybrid vehicle] and 1.3 times higher than the [hybrid vehicle] for highway driving,” the researchers said in their recently published paper. “These ratios exceed the factors that EPA fuel economy values would predict for these vehicle types.”

Why is this important?

Because clients are buying hybrids for their fuel-saving character, which makes accuracy an even more important feature in this matter. And since most buyers make a purchase decision based on such ratings, it goes without saying that they should have access to the correct figures, relevant to the environment where the car will be used.
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