Gasoline may be averaging around $2.50 a gallon right now, but gas mileage remains an important factor in choosing a new car.

Now the EPA has released 2010 fuel efficiency figures for all new cars and trucks sold in the U.S. Hybrids from Ford, Honda, Lexus, Mazda, Mercury, Nissan, and Toyota dominated the ratings.

Perhaps not surprisingly, the best gas mileage of any new vehicle comes from the 2010 Toyota Prius. The quintessential hybrid is rated at 51 mpg city / 48 mpg highway, for a combined rating of 50 mpg.

2010 Ford Fusion Hybrid

2010 Ford Fusion Hybrid

2007 Honda Civic Hybrid 4dr Sdn w/Navi exterior rear right

2007 Honda Civic Hybrid 4dr Sdn w/Navi exterior rear right

2010 Honda Insight - front three-quarter

2010 Honda Insight - front three-quarter

Though ithe HS is not a performance hybrid like other Lexuses, neither is it a pure economy car

Though ithe HS is not a performance hybrid like other Lexuses, neither is it a pure economy car

The EPA's FuelEconomy.gov website offers a downloadable guide that rates all new vehicles, but they are broken into categories, from two-seaters through sport-utility and special-purpose vehicles. Some vehicles do not have to be rated because they weigh more than 6,000 pounds (Hummer H2, anyone?).

But to get an overall Top 10 list, you have to set aside the guide and use the website's search function. We've grouped together vehicles from the same maker that are sold under different brands (the Ford Escape Hybrid and its Mercury and Mazda siblings, for example).

Doing that gives the following Top 15 list (ranked by city mileage):

  • 2010 Toyota Prius (51 mpg city / 48 mpg highway)
  • 2010 Ford Fusion Hybrid / Mercury Milan Hybrid (41 mpg city / 36 mpg highway)
  • 2010 Honda Civic Hybrid (40 mpg city / 45 mpg highway)
  • 2010 Honda Insight (40 mpg city / 43 mpg highway)
  • 2010 Lexus HS 250h (35 mpg city / 34 mpg highway)
  • 2010 Nissan Altima Hybrid (35 mpg city / 33 mpg highway)
  • 2010 Ford Escape Hybrid / Mazda Tribute Hybrid / Mercury Mariner Hybrid (FWD, 34 mpg city / 31 mpg highway)
  • 2010 Smart ForTwo (33 mpg city / 41 mpg highway)
  • 2010 Toyota Camry Hybrid (33 mpg city / 34 mpg highway)
  • 2010 Audi A3 TDI automatic (30 mpg city / 42 mpg highway)
  • 2010 Volkswagen Golf TDI automatic (30 mpg city / 42 mpg highway)
  • 2010 Volkswagen Jetta TDI automatic (30 mpg city / 42 mpg highway)

It's worth noting that modern clean diesels get higher mileage in real-world use than their EPA ratings, so the Audi and Volkswagen TDI models may do better than their position on this list.

And the bottom of the list? The worst mileage comes from supercars made by Aston Martin, Bentley, Ferrari, and Lamborghini. Don't even ask.

[2010 Fuel Economy Guide]