The 2009 Volkswagen Jetta TDI Clean Diesel (Courtesy of Volkswagen of America)

So here’s the scoop…Volkswagen is currently running an ad on television that touts some pretty impressive mile-per-gallon stats. The commercial features a 2009 Volkswagen Jetta TDI Clean Diesel and if you’re not paying careful attention you just may get the impression that it gets 58 miles per gallon. That’s pretty remarkable, right? But is Volkswagen being deceptive?

I think this will be easier for both of us if you watch the commercial right now. It’s just one of several “Meet the Volkswagens” ads that you may have seen on television recently. Go ahead, I’ll wait for you to come back. It’s only a 30-second spot.

OK, so now you’ve seen for yourself how clever this ad is in its delivery. It’s actually pretty easy to come away thinking that the featured Jetta is rated at 58 miles per gallon. But pay careful attention to the fine print in the ad. While VW’s Max the Beetle is telling his neighbor, “A TDI set a Guinness World Record 58 miles per gallon,” the small type on the screen tells a much different story. It clearly states, “Current world record for lowest fuel consumption across the 48 contiguous United States. Your mileage will vary. EPA estimates. 30 city/41 highway mpg.” The last time I checked, 30 city and 41 highway don’t exactly average out to 58 miles per gallon.

I think it’s important to note that Volkswagen isn’t lying or directly telling you that you can expect to get 58 miles per gallon in the Jetta TDI — they’re just stating that it’s been done before. In this case, it was in the hands of Helen and John Taylor. That’s the couple that drove the Jetta cross-country to the record breaking 58 miles per gallon — 58.82 mpg, if you really want to be precise — and they’re hypermilers. In fact, they’ve been called the world’s most fuel-efficient couple.

The numbers that you should really be paying attention to are the Jetta’s EPA fuel economy ratings of 30 mpg in the city and 41 mpg on the highway. Those are the stats that you’d find on the Jetta’s window sticker at your local VW dealership — and those are the numbers that were determined by the United States Environmental Protection Agency. And the ratings are pretty accurate, too. In fact, as of the 2008 model year, they’re quite a bit more accurate than they have been in the last few decades. That’s because the tests that the EPA uses to determine fuel economy have been updated and improved. The EPA’s original city and highway mileage tests were designed based on the public’s driving habits in the 1960s. It wasn’t until 1985 that the EPA’s city and highway tests were revised, but even then the numbers reflected slower highway speeds, fewer in-car accessories and slower acceleration. As you can imagine, by 2008 the test was in need of another update. The EPA added three new tests in order to adjust the city and highway numbers accordingly — a high-speed test, an air conditioning test and a cold temperature test are now part of the EPA’s routine.

You can find the updated fuel economy information for most cars and trucks (dating back to 1985) by visiting fueleconomy.gov.

If you’re looking for a little more detail about the new calculations, you can read an article on HowStuffWorks.com that’s called How the 2008 EPA Fuel Economy Ratings Work. And if you’re still hungry for more info, on July 7, we’ll be releasing a High Speed Stuff podcast on iTunes where we’ll go into some greater detail about how the EPA calculates fuel economy.

More fuel-efficient stuff:
How EPA Fuel-Economy Testing Works
How the 2008 EPA Fuel Economy Ratings Work
HowStuffWorks – Fuel Economy Library
Consumer Guide Automotive – New Cars with EPA Over 30 mpg
What is hypermiling?