Outdated Tests Inflate Fuel Efficiency Scores on All Vehicles
By PAUL ENG
Dec. 10, 2004 - How many miles can your car travel on a single gallon of gas? If you think it's close to the fuel efficiency estimates provided by the Environmental Protection Agency, you'd probably be right. That is, unless you own one of those highly touted hybrid models.
The EPA has been reviewing its testing methodology and is asking car makers and other testing organizations to weigh in with their comments and suggestions. Millett says the agency has received a good deal of information and is confident it can propose changes and improvements to its lab procedures by next year.
Flawed Fuel Factors
But EPA critics, such as the Union of Concerned Scientists in Cambridge, Mass., say the disparities in fuel efficiency numbers for hybrids underscore a much larger problem: That the EPA's fuel efficiency tests are fundamentally flawed for all cars.
David Friedman, research director of the group's clean vehicles program, says the basic EPA testing parameters -- designed to capture emissions and pollution data -- are based on driving habits of decades past.
"The base test is 30 years old," said Friedman. "I wasn't driving back then, but it was a pretty different world."
According to Friedman's group, some of the more glaringly outdated driving assumptions and conditions that are still being used by the EPA in its efficiency tests include:
- Low highway speeds. The EPA test assumes an average car speed of 48 mph and a maximum of 60 mph. Most state highway speed limits are now set at 65 mph or higher. At those speeds, fuel economy can drop by almost 10 percent to 17 percent, compared to 55 mph.
- Easy acceleration. The maximum acceleration rate is 3.3 mph per second, or equivalent to taking about 18 seconds to go from 0 to 60 mph. By the EPA's own data, most drivers today accelerate nearly five times harder. The harder the acceleration, the more gas wasted.
- Overestimated trip lengths. The EPA's "city" tests assume a trip of 7.5 miles. But even recent EPA figures show the average urban drive lasts five miles or even half that, at 2.5 miles. Shorter trips mean car engines do not have the time to warm up and operate efficiently.
- Exclusion of air conditioning and other accessories. Rare luxury items 30 years ago, air conditioners are practically standard features on nearly every new vehicle in the United States. Heavy use of air conditioning and other accessories mean a severe reduction in fuel efficiency -- especially in stop-and-go traffic conditions.
"These testing cycles don't represent how people drive today," said Friedman. "They just aren't realistic."
ABC News
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Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by IsrAmeriPrius, Dec 10, 2004.
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Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by IsrAmeriPrius, Dec 10, 2004.