Weight gain of U.S. drivers has increased nation's fuel consumption
James E. Kloeppel, Physical Sciences Editor
217-244-1073; kloeppel@[EMAIL PROTECTED]
photo to enlarge
Photo by L. Brian Stauffer
Sheldon H. Jacobson, professor of computer science, and his former
graduate student, now a professor at Virginia Commonwealth University,
have found that weight gain of U.S. drivers has increased the nation's
fuel consumption.
CHAMPAIGN, Ill. — As American waistlines have expanded since 1960, so
has their consumption of gasoline, researchers at the University of
Illinois at Urbana-Champaign and Virginia Commonwealth University say.
Americans are now pumping 938 million gallons of fuel more annually than
they were in 1960 as a result of extra weight in vehicles. And when gas
prices average $3 a gallon, the tab for overweight people in a vehicle
amounts to $7.7 million a day, or $2.8 billion a year.
The numbers are added costs linked directly to the extra drain of body
weight on fuel economy. In a paper to appear in the October-December
issue of the journal The Engineering Economist, the scientists conclude
that each extra pound of body weight in all of today’s vehicles results
in the need for more than 39 million gallons of extra gasoline usage
each year.
“The reason we looked at this issue was that gas prices hit an average
exceeding $3 per gallon in September 2005,” said Sheldon H. Jacobson, a
professor of computer science and director of the simulation and
optimization laboratory at Illinois.
“This was the highest recorded level in the United States. We thought
there must be some way that we could determine how to quantify the
effect of being overweight on fuel consumption. We felt that beyond
public health, being overweight has many other
socio-economic implications.”
Jacobson presented the challenge to Laura A. McLay, who was a doctoral
student in his laboratory at that time and is now on the faculty at
Virginia Commonwealth University, and they pursued the issue through his
funding with the National Science Foundation.
Their conclusions are based on mathematical computations drawn from
publicly available data on U.S. weight gain from 1960 to 2002, a period
in which the weight of the average American has increased by more than
24 pounds, according to data from the U.S. Department of Health and
Human Services.
By 2002, 62 percent of adults were overweight with a body mass index of
between 25 and 30; more than 30 percent were considered obese with a BMI
exceeding 30.
The fuel-consumption calculations apply only to passenger vehicles,
including cars and light trucks driven for non-commercial reasons. Ruled
out were other factors such as increasing the weight of cargo or
decreasing fuel efficiency through poor maintenance. Driving data
collected in 2003 were used to gauge fuel consumption based on weight
gains during the last four decades.
The researchers used three different scenarios that considered not only
beefier drivers behind the wheel but also their passengers, accounting
for individual characteristics such as ages, numbers of people in the
vehicle, and expected weights.
Since 1960, McLay and Jacobson said, the consumption of no less than 938
million gallons of gasoline annually can be attributed to weight gains
of drivers and passengers. Of that total no less than 272 million
gallons are consumed annually as a result of weight gains since 1988.
“The key finding is that nearly 1 billion gallons of fuel are consumed
each year because of the average weight gain of people living in the
United States since 1960 – nearly three times the total amount of fuel
consumed by all passenger vehicles each day based on current driving
habits,” McLay and Jacobson wrote.
“Although the amount of fuel consumed as a result of the rising
prevalence of obesity is small compared to the increase in the amount of
fuel consumed stemming from other factors such as increased car reliance
and an increase in the number of drivers, … it still represents a large
amount of fuel, and will become even more significant as the rate of
obesity increases.
The conclusions, Jacobson said, should be considered conservative
because they do not consider many indirect consequences of obesity nor
the increase in the number of vehicle miles linked to more people living
in the United States and owning cars.
Editor’s notes: To reach Sheldon Jacobson, call 217-333-1043.
To reach Laura McLay, call 804-828-6052.
The original draft of this news release was written by Jim Barlow, who
has since become the director of science communications for the
University of Oregon.
News Bureau, University of Illinois at Urbana-Champaign
616 E. Green St., Suite D, Champaign, Illinois 61820-6261
Telephone 217-333-1085, Fax 217-244-0161, E-mail news@[EMAIL PROTECTED]
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