On Thursday, the US Environmental Protection Agency is set to release its proposed new standards for measuring automobile gas mileage. The new guidelines are intended to be closer to real-world automobile use than the current ones.
Under its new program, the E.P.A. plans to take into account factors used by the agency in measuring vehicle emissions. They include how a car performs in high-speed driving, defined as 80 miles an hour or more; aggressive driving, in which a vehicle accelerates more than 3.3 miles per second; while air-conditioning is in use; and during cold temperatures. All these factors can affect a vehicle's fuel economy.
(Great -- the EPA is adding "illegal," "irresponsible" and "known to degrade mileage at all times" factors to the mix.)
It's likely that most vehicles will see a drop in their mileage ratings under these new metrics, including hybrids.
"It's likely that most vehicles will see a drop in their mileage ratings under these new metrics, including hybrids."
That's actually a good thing in my opinion as it basically amounts to tighter CAFE standards without actually having to raise CAFE. If the mileage ratings for vehicles take a hit due to the fact that they now represent more realistic (and yes, 'illegal', 'irresponsible' and 'innefficient') driving habits, the corporate average fuel economy for each company will go down, forcing them to either sell more smaller cars or develop more efficient versions of larger cars.
Also, these new standards will likely effect larger cars more than smaller due to the higher drag coefficients of bigger cars (less aerodymanic) which will be more noticable in the high speed driving portion of the test as well as heavier mass which will have more of an effect on the aggressive acceleration portion of the test. So these new standards will also have the effect of penalizing larger cars, which is also not bad in my opinion.
It will be interesting to see the new numbers for various vehicles soon...