Carnegie Mellon Researchers Report Hybrid Cars Are Greener for City Drivers

 Carnegie Mellon Researchers Report Hybrid Cars Are Greener for City Drivers

PR Newswire

PITTSBURGH, June 17, 2013

PITTSBURGH, June 17, 2013 /PRNewswire/ --Will that hybrid vehicle pay for
itself and help the environment? That depends on how and where you drive,
Carnegie Mellon University researchers report.

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Jeremy Michalek, a professor of mechanical engineering and engineering and
public policy at CMU, and Orkun Karabasoglua, a mechanical engineering
research assistant, analyzed the potential cost and greenhouse gas savings of
hybrid and electric vehicles under different driving conditions.

"We found that for highway drivers, hybrid and plug-in vehicles cost more
without much benefit to the environment," Michalek said. "But for drivers who
experience a lot of idling and stop-and-go traffic, a hybrid could lower
lifetime costs by 20 percent and cut greenhouse gas emissions in half."

The study, funded by the National Science Foundation, Ford and Toyota, appears
in the journal Energy Policy as the EPA is rolling out new fuel economy labels
starting with 2013 vehicles.

"The new labels are improved, but no single test can capture all kinds of
driving," Michalek said. "Hybrid and plug-in vehicles will do the most good at
the lowest cost if adopted by drivers who spend a lot of time in traffic. For
these drivers, hybrids are a win-win, and the benefits may be much more than
the labels suggest."

The U.S. government uses standard laboratory tests to measure vehicle fuel
efficiency for federal fuel economy labels and standards.

"The fuel economy standards are still based on old lab tests that make
vehicles appear to be more efficient than they really are," Michalek said.
"This has always been an issue, but it is simplified with today's vehicle
technologies. These tests may be underestimating the relative real-world
benefits of hybrid and plug-in vehicles." 

Driving conditions affect not only cost and emissions, according to Michalek.
"Aggressive driving can cut vehicle range by 40 percent or more. That's a
notable risk for pure electric vehicles, which already have limited range and
take a long time to recharge. But with hybrid electric vehicles, which run on
gasoline, and plug-in hybrid electric vehicles that use electricity for short
trips and switch to gasoline for longer trips, there's no added risk of being
stranded," he said.

Michalek reports that "the bottom line is: before you buy, consider how you

About Carnegie Mellon University: Carnegie Mellon ( is a private,
internationally ranked research university with programs in areas ranging from
science, technology and business, to public policy, the humanities and the
arts. More than 12,000 students in the university's seven schools and colleges
benefit from a small student-to-faculty ratio and an education characterized
by its focus on creating and implementing solutions for real problems,
interdisciplinary collaboration and innovation. A global university, Carnegie
Mellon's main campus in the United States is in Pittsburgh, Pa. It has
campuses in California's Silicon Valley and Qatar, and programs in Africa,
Asia, Australia, Europe and Mexico. The university has exceeded its $1 billion
fundraising campaign, titled "Inspire Innovation: The Campaign for Carnegie
Mellon University," which aims to build its endowment, support faculty,
students and innovative research, and enhance the physical campus with
equipment and facility improvements. The campaign closes June 30, 2013.

SOURCE Carnegie Mellon University

Contact: Chriss Swaney, 412-268-5776,
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