Proposed changes to corporate average fuel economy (CAFE) standards may cause vehicles to get bigger instead of smaller by the 2014 model year, according to a study by the University of Michigan (UM).
Researchers said “a loophole” exists in the new formula for calculating miles per gallon. Should auto makers choose to act upon that incentive, it would be more difficult to achieve the policy's goal of reducing fuel consumption.
Steven Skerlos, an associate professor in the UM Department of Mechanical Engineering, said he believes auto makers will indeed try to take advantage of the unintended consequence of the new policy.
“For just about all the scenarios, the car got bigger,” Mr. Skerlos said. “What you can model in a computer is different from reality, but based on this research we expect it to happen.”
The study, released in mid-December, used simulations to mimic real-life choices auto makers must make in redesigning vehicles to meet changing standards.
In July, the Obama administration said it plans to increase the U.S. fuel-economy standard for cars and light trucks to 54.5 mpg in the 2025 model year from 35.5 mpg in 2016. The U.S. Environmental Protection Agency (EPA) and the Department of Transportation estimate the changes will help reduce the nation's dependence on oil by an estimated 12 billion barrels between 2011 and 2016, as well as reduce oil consumption by 2.2 million barrels per day by 2025.
For years, U.S. auto makers criticized traditional CAFE standards, saying they unfairly rewarded production of slimmer, lighter vehicles that could put vehicle makers' light truck- and SUV-oriented markets at a disadvantage against Asian competitors.
In response, the new formula for determining miles per gallon became one that measures a vehicle's “footprint”—calculated by multiplying wheelbase by track width so larger vehicles had lower fuel-economy targets. The loophole in the proposed new CAFE standards: The footprint formula favoring larger vehicles is retained.
Crystal ball needed
The UM study used more than 450 vehicle makes and models to figure how auto makers could modify vehicle dimensions, implement fuel-saving technology features and trade off acceleration performance and fuel economy.
“It's cheaper to make large vehicles, and meeting fuel-economy standards costs (manufacturers) money in implementing and looking at what consumers will purchase,” said Katie Whitefoot, another researcher involved with the study.
Not only would the trade-offs auto makers consider in redesigning a vehicle undermine the CAFE policy as it stands, they would increase pollution as well, according to the study.
“The adjustment to the CAFE standards tries to achieve high fuel economy while not compromising vehicle size,” Mr. Skerlos said in a statement. “The idea here is these things intersect and you have an equivalent of three to 10 coal-fired power plants hidden in that trade-off.”
Over their lifetimes, larger vehicles would generate between three and 10 1,000-megawatt coal-fired power plants' worth of excess carbon emissions, the study said. By comparison, a 1,000-megawatt plant could provide power for more than half a million people.
“We still see that fuel economy standards overall reduce pollution,” Ms. Whitefoot said, “but they don't as much as they could have because this incentive exists.”
Traffic safety risks
Ms. Whitefoot and Mr. Skerlos also noted higher traffic safety risks associated with larger vehicles, suggesting regulators create a policy that addresses fuel-economy goals and safety.
In addition, the pair suggested reducing the value of meeting targets based on vehicle footprint and allowing for modifications to the standards if fuel-economy goals will not be met.
Policymakers are developing CAFE regulations for vehicles produced from 2017 to 2025 and plan to finalize those regulations by July 2012.