If you search for "2019 Honda Civic mpg" you will get a single number from most sites. That number is almost always wrong, not because anyone lied, but because the car does not have a single mpg figure.
The EPA does not certify a model. It certifies configurations. For the 2026 Civic alone there are seven certified rows, and the combined figure runs from 24 to 49 mpg. Both numbers are correct. They describe different cars that share a nameplate.
Every row in the EPA dataset is a unique combination of:
Automatic (AV-S7))Change any one of those and the EPA tested a different vehicle. The Civic's 49 mpg figure belongs to one specific hybrid configuration. The 24 mpg figure belongs to a turbocharged manual car. Publishing one of them as "the" Civic figure is a choice to mislead somebody.
Because a single number is a better search snippet. "49 mpg combined" is a cleaner thing to put in a title tag than "24 to 49 mpg depending on configuration."
We made the opposite trade. Our headlines carry the range, and the model-year page breaks it down configuration by configuration with the transmission and drive type attached to each row. It is uglier in a search result and far more useful to the person who clicked.
The EPA dataset includes adjusted and unadjusted city and highway values. Unadjusted figures are the raw test-cycle results before the EPA applies its correction factors. They are published, they are real, and they are not what appears on a window sticker.
Mixing the two is a common and quiet form of error: quote unadjusted highway numbers and every car suddenly looks more efficient. We publish the adjusted values, which is what a buyer will see on the lot, and we label the source row so the figures can be checked.
The whole dataset is a public CSV:
https://www.fueleconomy.gov/feg/epadata/vehicles.csv.zipEvery configuration row on this site maps to a row in that file by EPA vehicle ID and engine ID. If a figure here disagrees with that file, we got it wrong and we want to know.