When you see that magic 40-miles-per-gallon number in a car ad, does it make you pay attention?

Most likely it does. (Among other things, it's usually in much larger type than the other two EPA ratings.)

But how seriously should you take any publicized gas-mileage ratings?

Most people seem to know that, as the old saying goes, Your Mileage May Vary.

Now a group called Consumer Watchdog has filed a lawsuit--on behalf of plaintiff Louis Bird of Sacramento, California--complaining that Hyundai used only the 40-mpg highway mileage rating in its television ads for the current Elantra compact sedan.

Bird is seeking to have the suit declared a class action, on behalf of all Elantra buyers who did not achieve 40 mpg.

He says that he bought his 2011 Hyundai Elantra based on the TV ads showing 40 mpg, that his car is not delivering that fuel efficiency, and that he is consequently paying more for gasoline than he expected to based on the ad.

Bird asks for unspecified damages to be levied against Hyundai for alleged violations of consumer protection and fraud laws in the state of California.

Hyundai responded with a statement in which it says tests by not only the government agency but major auto publications “suggest the advertised fuel economy is realistic.”

Consumer Watchdog has some previous history with Hyundai, having publicly called on the EPA last December to retest the 2011 Elantra's fuel efficiency by conducting tests in its own facility, rather than accepting Hyundai's test results.

At the time, the consumer group claimed that the Elantra achieves only gas mileage in the mid-20s under real-world conditions, according to its research director Judy Dugan.

She cited "a trail of disappointed drivers," pointing to Elantra owner postings in online forums, as well as published results from road tests by USA Today and Motor Trend, and a 20-mpg city-driving result by Consumers Union.

2011 Hyundai Elantra

2011 Hyundai Elantra

In response, the carmaker's national manager of product PR, Jim Trainor, said Hyundai stood by the EPA numbers. He countered with the figure achieved for highway mileage by Consumer Union in the same test of a 2011 Elantra: 39 mpg.

Based on coverage by various outlets, commenter sentiment is running against Bird. But as these kinds of things go, the case may nonetheless wind its way through the courts for a while.

Once again: The mileage of any car, even high-MPG hybrids, will vary significantly with speed, driving style, temperature, accessory use, and many other factors.

And many people don't know that tips for getting higher gas mileage are widely available--or, worse, they aren't aware that some commonly-believed gas mileage tips are myths.

But we're curious: Do you think Bird has a case? How seriously do you take advertised gas-mileage ratings for new cars?

Leave us your thoughts in the Comments below.


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