University of Michigan Reports That Cars are the Most Inefficient Form of Transportation (Inhabitat)

By Timon Singh, Published on January 15th, 2014

You’d be mistaken for thinking that due to their size and power, commercial jets would be inefficient when it comes to fuel consumption. However, according to a new report from the University of Michigan, planes are among the most efficient forms of transportation. In fact, according to the report, the fuel economy of standard road vehicles must improve 57% in order to match the current energy efficiency of commercial airline flights.

university of michigan, air travel, car travel, fuel efficiency, BTU, transport fuel efficiency

Michael Sivak, a research professor at the U-M Transportation Research Institute, wrote the report after examining trends in the amount of energy needed to transport a person a given distance in a light-duty vehicle, such as car, van or SUV. He compared his findings to that of a scheduled airline flight, measuring the BTU per person mile from 1970 to 2010.

Sivak 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 to match the efficiency of planes. Either that, or the 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.”

The report also stated that the 14.5 million light vehicles sold in the US over 2012 accounted for only 6% of the entire fleet of light vehicles on the road.

“A historical perspective illustrates the daunting task,” Sivak added. “An improvement of at least 57 percent in vehicle fuel economy of the entire fleet of light-duty vehicles would be required, but from 1970 to 2010, vehicle fuel economy improved by only 65 percent.”

Interestingly, while the energy intensities of both driving and flying have steadily decreased over the last 40 years, the improvement and fuel efficiency for air travel has been substantially greater than driving—a staggering 74% versus 17%.

“It is important to recognize that the energy intensity of flying will continue to improve,” Sivak said. “Because the future energy intensity of flying will be better than it currently is, the calculations underestimate the improvements that need to be achieved in order for driving to be less energy-intensive than flying.”

And how do trains stack up? Well, in 2010 the BTU per person mile was 4,218 for driving versus 2,691 for flying. For trains it was 1,668, buses had 3,347 and motorcycles had 2,675.



One thought on “University of Michigan Reports That Cars are the Most Inefficient Form of Transportation (Inhabitat)

  1. I thought this was kind of an antiquated approach, frankly. There are a lot of ways we might compare the impacts of different fossil-fuel-powered transport modes. Passenger-miles-per-gallon, though not a bad first cut, falls short in my view of where our thinking is today. The infrastructure required to enjoy these modes is a non-trivial (and on-going) investment in fossil fuels that this approach omits. Airports, highways, train tracks are just the beginning.

    Secondly, as some recent work by scientists at IIASA points out, the first order impacts measured as fuel consumption are not always the most important thing to know about a given mode.

    “According to the paper, if we focus just on the impact over the next five years, then planes currently account for more global warming than all the cars on the world’s roads – a stark reversal of the usual comparison. Per passenger mile, things are even more marked: flying turns out to be on average 50 times worse than driving in terms of a five-year warming impact.”

    and the article to which it refers:

    Furthermore, focusing on fairly small gradations among these modes (so calculated) obscures and draws attention away from the fact that we are on the hook to wean ourselves from all of them. Just like the timeworn *paper or plastic* misses the larger point so too does this approach.

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