With estimates being revised downwards, will the standards manufacturers have to meet for fleet mileage be revised downwards? If not, it at least will effectively serve to up manufacturer's fleet mileage (in the absence of the Bush admin's willingness to do so). It won't be enough, but at least it's something ..
Carl Bialik
EPA Improves Its Mileage Estimates,
But Stats Still Don't Tell the Whole Story
January 12, 2007
http://online.wsj.com/public/article/SB116852698135573876-yPA3ncIcKiUTWQqIBAL1DAT9ddU_20080112.html (free today; may change)
Jumping to the last paragraph:
Focusing on consumption rather than mpg ratings can make a big difference. Consider this example: Compare a compact car that today is labeled at 40 mpg, and a sport utility vehicle rated at 12 mpg. Suppose both are being driven 15,000 miles a year. The compact would use 375 gallons of gas a year, and the SUV would require 1,250 gallons -- or 875 gallons more than the car. Now suppose that the compact's mpg estimate drops by 20% to 32 mpg, and the SUV's drops by just 10% to 10.8 mpg. At first glance, it seems the compact has suffered more from the change. But crunch the numbers, and you'll see that 15,000 miles of driving would consume 920 more gallons in the SUV than in the compact. The small car's advantage increased by 45 gallons.
then jumping back to near the top (5th paragraph)
But caveats remain about the new fuel-economy labels, including their reliance on what is essentially a treadmill test of cars, which still may not accurately capture real-world performance. Also, some critics say the focus should be on annual fuel cost, not miles per gallon. Some cars with particularly high mpg ratings, including hybrids, will appear to take the biggest hit under the new rules, when in fact their advantage over lower-economy cars could end up being even greater (more on that in a bit).
skipping a few paragraphs ...
The new mpg ratings take into effect faster speeds (80 miles per hour, instead of 60) and quicker acceleration (eight miles per hour, per second, instead of 3.2.) They also consider the use of air conditioning and driving in cold weather. In general, average city mpg will drop by 12%, and highway will decline by 8%, the EPA says.
The EPA conducted road tests of vehicles, including a test of more than 600 cars in Kansas City in 2004 and 2005, to calculate the effect of the new factors. Then it derived averages for each vehicle class. For now, auto makers are free to use these class-average revisions, or to run their own EPA-monitored tests on each model. But by the 2011 model year, all models must be individually tested. (Current mileage estimates are based on tests car makers conduct using EPA guidelines. The EPA runs its own tests on 10% to 15% of the cars to make sure there are no significant discrepancies.)
and skipping another few:
For its tests, Consumer Reports used its Colchester, Conn., test track and the roads nearby, comparing 303 models with EPA numbers and finding discrepancies as great as 35% to 50% for city-driving numbers. Unlike Edmunds and the auto club, Consumer Reports directly measured fuel usage with a meter situated between the tank and the engine. The organization said that method is superior to the one generally employed by car owners, which is to compare distance traveled with how many gallons are required to fill up the tank -- with "full" measured by the automatic sensors in gas pumps.
... a few more paragraphs before the last (which is pasted in above)
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Sorry for all the skips but since the WSJ usually requires a subscription, I wanted to paste in the most informative parts of the article, as most people don't subscribe. Most of what is missing either deals with the issue of the earlier EPA standards not doing a good job, or anecdotal stories of how people noticed their mileage was considerably less than the EPA estimates.
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