What it is the sound of one hand clapping? What is a life worth living? What is the real fuel economy of a given vehicle? There are no right answers to these deep imponderables of life. Especially when it comes to determining an absolute number for the miles-per-gallon of a hybrid or any other vehicle.

Even after the Environmental Protection Agency adjusted its out-of-date and inaccurate numbers, uncertainty remains. Maybe we should turn to professional road test reviewers for real mpg numbers on new vehicles?

Compare EPA fuel economy numbers for the Escape Hybrid with numbers published by the auto press:

EPA 33/29 (city/highway)
Car and Driver 33/28 (city/highway)
Edmunds 26 (combined)
Motorweek 32 (combined)
Familycar.com 42 (highway)

Fuel economy numbers from the auto press show a similar ten to fifteen percent range for other hybrids.

Are their numbers for the two-wheel drive or four-wheel drive Escape? What was the temperature outside? Was the A/C used? How fast did the driver accelerate and how many stops were on the course? The devil is in the details. When details are provided, the picture comes into sharper focus. For example, Automobile Magazine’s review of the 2005 Accord Hybrid showed the highway mileage at 29 mpg, a full eight miles or 22 percent off the EPA’s highway number. Only when the writer reveals that he boogied at 80 mph for most of the trip does the story start to make sense. Speeding kills fuel economy for any vehicle. Unfortunately, the reviewers often leave out critical details.

Now, you can begin to see why consumers, with a wide array of driving courses and styles, see such a range of mpg numbers. Of course, the drivers who get less than the advertised EPA numbers are going to point to the carmaker. But perhaps they should follow the lead of Gary LaBouff, director of research and development for New York City Transit’s Department of Buses. He meticulously tracks fuel economy for his fleet of 100 plus hybrid buses. When pressed on fuel economy numbers for his hybrids, he says, “It depends.”