Michael Sivak, a research professor at the U-M Transportation Research Institute, examined recent trends in the amount of energy needed to transport a person a given distance in a light-duty vehicle (cars, SUVs, pickups and vans) or on a scheduled airline flight. His analysis measured BTU per person mile from 1970 to 2010.
He found that the entire fleet of light-duty vehicles would have to improve from the current 21.5 mpg to at least 33.8 mpg, or vehicle load would have to increase from the current 1.38 persons to at least 2.3 persons.
“It would not be easy to achieve either of these two changes,” Sivak said. “Although fuel economy of new vehicles is continuously improving, and these changes are likely to accelerate given the new corporate average fuel economy standards, changes in fuel economy take a long time to substantially influence the fuel economy of the entire fleet—it takes a long time to turn over the fleet.”
For example, he says, the 14.5 million light vehicles sold in 2012 accounted for only 6 percent of the entire fleet of light vehicles on the road.
Read more at: Phys.org