Auto Show Blog

Category: Thoughts at large

Will these 'green' cars deliver in the real world?

You expect a bit of hyperbole at an auto show, but this year some claims really are stretching credibility. The need to be green - shifting consumer preferences and government rules come to mind - is pressuring manufacturers to at least appear to be tackling the issue of oil dependency and fuel consumption. Surely they wouldn't exaggerate, would they?

We've heard Toyota Motor Corp. claim the new Prius gasoline electric hybrid sedan would deliver an average 50 mpg, up from the previous model's 46 mpg. The Chinese company BYD Auto said its E6 all-electric vehicle will travel up to 250 miles on one charge and only takes 10 minutes to recharge 50 percent of the battery. BMW's Mini E - "E" for electric - can transport driver and passenger 150 miles on a single charge, or drive all the way around Lake St Clair.

Ford, GM and Chrysler strain credulity with claims that various SUV behemoth monsters can deliver, say 34 mpg. But the secret is in the qualifying language, or the way you actually calculate the numbers. Those SUV claims usually refer to "highway" driving, where even the most humungous of trucks, driving down a slight gradient with a following wind, can achieve impressive fuel economy.

In Britain, Toyota has claimed for years in its advertising that the Prius will achieve the equivalent of 54 miles per U.S. gallon. In reality, "normal" driving won't get you much more than about 34 mpg. It's true that 34 mpg is a pretty impressive performance anyway, although in Europe many diesels can attain comparable fuel economy with much better performance. The Prius, though, gets the accolades as a green machine. Toyota does admit that if you drive the Prius on the highway, it won't perform as well, economically. It does its best work in the city.

In Europe, as in the United States, fuel economy ratings are calculated using methods that have absolutely no reality to everyday driving. European manufacturers take their cars into laboratories, hook them up to a computer and use the results to rate the vehicles in city, highway, and "combined" - or an average. The bad news is that these numbers have absolutely no relationship with real road conditions and often exaggerate outcomes by up to 30 percent. The good news is that you have a great way to perfectly compare how competing cars will perform in conditions that will have nothing in common with your actual driving.

BYD of China's E6 may well be able to travel 250 miles on a single charge, but until it supplies a car for journalists to test, the suspicion will remain that this could only be done by driving at about 10 mph. Accelerate even a little bit aggressively, and you are unlikely to fall well short of 250 miles. The same goes for the electric Mini.

When the show is over and the new cars and trucks show up at the dealerships, will they live up to these extravagant claims?