The 2011 Toyota Corolla is one of the best-selling compact sedans in the U.S. market.

But its gas mileage isn't necessarily anything to write home about.

The most fuel-efficient model is the one fitted with the 132-horsepower, 1.8-liter engine and a five-speed manual gearbox, a transmission many U.S. buyers will shun for an automatic.

That five-speed manual Corolla is rated at 28 mpg city, 35 mpg highway, for a combined gas mileage rating of 31 mpg.

Switching to the ancient four-speed automatic transmission with that same 1.8-liter engine, as most buyers do, brings the numbers down to 26 mpg city, 34 mpg highway, with a combined rating of 29 mpg.

And for the 2011 Corolla, the picture gets even worse if you opt for the more powerful 158-horsepower, 2.4-liter four-cylinder engine.

With either a five-speed manual gearbox or the more popular five-speed automatic transmission, specifying the more powerful engine gives you mileage ratings of 22 mpg city, 30 mpg highway, for a combined number of 25 mpg.

That means Toyota isn't even close to hitting the magic 40-mpg mark for highway gas-mileage rating that many compact-sedan makers are using to tout the fuel efficiency of their Corolla competitors.

In fact, there are now 16 cars that rank at 40 mpg highway or better offered for sale in the U.S. The 2011 Toyota Corolla isn't one of them.

By comparison, the 2011 Hyundai Elantra compact sedan is rated at 29 mpg city, 40 mpg highway, for a combined rating of 33 mpg--and that's with either a six-speed manual or a six-speed automatic transmission.

And both Ford and Chevy offer special high-mileage models of their compact entries that get 40 mpg or better on the highway: the 2012 Ford Focus SFE and the 2011 Chevrolet Cruze Eco with six-speed manual, respectively.

If you want a Toyota with excellent gas mileage, there's still no substitute for the 2011 Toyota Prius hybrid, which gets 51 mpg city, 48 mpg highway, for a combined rating of 50 mpg.

And that's a number the Corolla has no hope of matching.

It's worth noting that the current Corolla went on sale as in January 2008 as a 2009 model, and it's now one of the oldest entries in the compact segment. We expect the next Corolla, perhaps for 2013, to do better in gas mileage.

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