- The entire on-road U.S. vehicle fleet averaged just 19.2 MPG in 2024, the highest in the 76-year EIA series but far below the 27.2 MPG EPA reports for new model-year-2024 vehicles.
- On-road passenger cars alone averaged 25.6 MPG in 2024, still 27% below the 35.3 MPG new cars achieve. On-road light trucks/SUVs averaged 18.5 MPG, 25% below new trucks' 24.6 MPG.
- Fleet-wide fuel economy was essentially flat for 24 years, from 16.4 MPG in 1990 to 17.5 MPG in 2014, despite major new-vehicle efficiency technology arriving during that span.
- Vehicles on U.S. roads average 10.3 years old (our own weighted calculation from 2022 NHTS survey data), meaning the on-road fleet mostly reflects a decade or more of past model years, not this year's new-vehicle ratings.
These are national averages; your actual fuel cost depends on your specific vehicle and location.
Calculate Your Exact Cost01 The Two MPG Numbers
Every year, the EPA announces a new-vehicle fuel economy record: model year 2024 hit 27.2 MPG, according to the EPA's own Automotive Trends Report, as documented in our average MPG by year analysis. But that number describes only vehicles built and sold in 2024. It says nothing about the roughly 280 million vehicles already on U.S. roads, most of which are considerably older.
EPA, The 2025 Automotive Trends Report (EPA-420-R-26-001), Table 3.1, model year 2024The U.S. Energy Information Administration tracks a different, complementary number: the actual fuel economy of the entire on-road fleet: every registered motor vehicle, of every age, actually being driven. In 2024, that figure was 19.2 MPG: the highest level ever recorded in EIA's 76-year data series, but 29% below the EPA's new-vehicle figure.
U.S. Energy Information Administration, Monthly Energy Review (July 2026), Table 1.8: Motor Vehicle Mileage, Fuel Consumption, and Fuel Economy, "All Motor Vehicles" column, 202402 76 Years of On-Road Fuel Economy
EIA has tracked on-road fleet fuel economy back to 1949, when the entire U.S. motor vehicle fleet averaged 13.1 MPG. That figure barely moved for the next quarter-century, bottoming out at 11.9 MPG in 1973, the year of the first oil crisis and the least efficient point in the entire series. Fuel economy standards enacted after 1975 then drove a sustained climb through the 1980s, reaching 16.4 MPG by 1990.
Calculated from U.S. Energy Information Administration, Monthly Energy Review, Table 1.8, "All Motor Vehicles" fuel economy column, 1949–199003 Cars, Trucks, and the Whole Fleet
EIA's "All Motor Vehicles" figure blends three very different categories: short-wheelbase light-duty vehicles (approximately passenger cars), long-wheelbase light-duty vehicles (approximately light trucks, SUVs, and vans), and heavy-duty trucks. In 2024, these ranged from 25.6 MPG down to just 7.5 MPG, and the heavy-duty category alone is enough to pull the blended average well below either light-duty figure.
U.S. Energy Information Administration, Monthly Energy Review, Table 1.8, 2024 row (all four vehicle-class columns)| Vehicle Class | On-Road Fleet (2024) | New MY2024 Vehicles | Gap |
|---|---|---|---|
| Cars | 25.6 MPG | 35.3 MPG | −27.5% |
| Light Trucks / SUVs / Vans | 18.5 MPG | 24.6 MPG | −24.8% |
| Heavy-Duty Trucks | 7.5 MPG | n/a | n/a |
| All Motor Vehicles (blended) | 19.2 MPG | 27.2 MPG | −29.4% |
Want to see exactly how your vehicle's fuel economy affects your own annual cost?
Use the Calculator04 Why the Gap Is So Large
Even comparing like with like (cars to cars, light trucks to light trucks), the on-road fleet trails new-vehicle ratings by roughly a quarter. The main reason is simple: most vehicles on the road aren't new. Using the U.S. Department of Transportation's 2022 National Household Travel Survey (the same public household-vehicle survey used elsewhere on this site), we calculated a nationally weighted average vehicle age of 10.3 years across the surveyed household vehicle fleet.
Calculated from U.S. DOT Federal Highway Administration, 2022 National Household Travel Survey, vehicle file (vehv2pub.csv), weighted by household weight (WTHHFIN)A vehicle bought a decade ago reflects a decade-old fuel economy rating, from before the most recent efficiency gains existed. Because the on-road fleet is an average across roughly the last 10–20 years of vehicle purchases, not just this year's, it will structurally always lag whatever the newest model year achieves, even if every single new vehicle sold keeps improving.
05 The Stalled Decades: 1990–2014
The clearest illustration of this lag is the 24-year stretch from 1990 to 2014, when on-road fleet fuel economy barely moved, from 16.4 MPG to 17.5 MPG, a gain of just 1.1 MPG in nearly a quarter-century. Our average MPG by year analysis documents why: new-vehicle fuel economy itself actually declined for much of this period (from 21.9 MPG in 1988 to a 30-year low of 19.3 MPG in 2004) as the market shifted heavily toward SUVs and pickups. With new vehicles not improving, and in some years getting less efficient, the on-road fleet had nothing better to average toward.
Calculated from EIA Monthly Energy Review, Table 1.8, "All Motor Vehicles," 1990 and 2014; cross-referenced with EPA 2025 Automotive Trends Report new-vehicle trend documented in average-mpg-by-year.htmlFleet-wide fuel economy only began climbing again after 2015, alongside renewed new-vehicle gains, and reached its all-time high of 19.2 MPG in 2024. That the on-road fleet number can now improve even as new vehicles keep shifting toward larger SUVs and trucks suggests hybrid and electric powertrains are starting to offset the class-mix effect that stalled progress in the 1990s and 2000s.
EIA Monthly Energy Review, Table 1.8, 2015–202406 Data Sources
- U.S. Energy Information Administration: Monthly Energy Review, Table 1.8, "Motor Vehicle Mileage, Fuel Consumption, and Fuel Economy," 1949–2024. eia.gov
- U.S. EPA: The 2025 Automotive Trends Report (EPA-420-R-26-001). epa.gov
- U.S. DOT Federal Highway Administration: 2022 National Household Travel Survey, vehicle file. nhts.ornl.gov