Compact cars are pretty much a known quantity, and hence easy to visualize. Many are headed for 40-mpg highway ratings, and Hyundai recently threw down the gauntlet in saying it would start to report sales of 40-mpg vehicles--and challenged other makers to do the same.

Imagine a compact car,and what do you see? Probably the newest or highest-volume vehicles in the class: Toyota Corolla, Honda Civic, the new 2011 Chevrolet Cruze or Hyundai Elantra, or the upcoming 2012 Ford Focus.

We're betting you don't see a 5,771-pound two-door car, more than 18 feet long, producing 453 horsepower from its 6.75-liter V-12 engine and returning a dismal 11 mpg city, 18 mpg highway for a combined mileage rating of just 14 mpg.

2011 Bentley Continental GTC And GTC Speed 80-11 Editions

2011 Bentley Continental GTC And GTC Speed 80-11 Editions


Nonetheless, it turns out that through its own arcane system of defining car classes, the U.S. Environmental Protection Agency considers the 2011 Rolls-Royce Phantom Coupe to be a compact car.

That's the class of car, it says, that offers from 100 to 109 cubic feet of interior volume for cargo and passengers combined.

Even more bizarre: The 2011 Bentley Continental GTC, which weighs 100 pounds less but offers 100 more horsepower from a 6.0-liter turbocharged W-12, is considered a subcompact (from 85 to 100 cubic feet).

Its mileage ratings are identical--11 mpg city, 18 mpg highway--though its combined rating is 1 mpg lower, at a mere 13 mpg.

If you own one of these undeniably luxurious, fast conveyances, and acquaintances ask what you drive, just say, "Oh, a little British compact car."

They'll never even ask about your mileage. Not, perhaps, that you may be overly concerned about such things.

[NYT Wheels Blog via Motor Authority]