The challenge of balancing vehicle weight with fuel economy was the central topic at a New England Motor Press Association and Massachusetts Institute of Technology conference last Thursday. Panelists representing auto manufacturers, academia and government affairs spoke about the impact of increased fuel economy standards on new car construction, materials and price.

The Cadillac ATS uses aluminum to safe
The Cadillac ATS uses aluminum to save weight and fuel. Graphic courtesy of General Motors.

Over the past 30 years, cars have become heavier. A 1983 Honda Accord has a curb weight of 2,300 pounds. The 2013 LX sedan model with an automatic transmission weighs 3,254 pounds. The growth in vehicle weight comes as a result of demand for larger cars with more entertainment and safety equipment. 

While everyone likes a safe, comfortable car, automakers are facing the fact that increasing vehicle weight decreases fuel economy. In 2012, the federal government mandated that all automakers must reach a corporate average fuel economy (CAFE) standard of 54.5 mpg for cars and light trucks by 2025. That means that the average fuel economy for all cars and light trucks that an automaker sells must be54.5 mpg or more. Automakers must now find a way to meet the fuel economy standards while still building safe cars that have the features consumers expect at a price they can afford.

Dave Leone, executive chief engineer, GM Global Performance Luxury Cars, said that while General Motors and other automakers are working to reduce vehicle weight and improve fuel economy, the result is that vehicle costs are rising. He pointed out that roughly 4 percent of the new car market is made up of hybrid and electric car sales, on which most car companies lose money. "We can afford to do that because of [profit] margins on other products," he said. However, shrinking profit margins on all cars means that prices will rise. "Cost will go up," as a result of higher fuel economy standards, he added.

Mike Stanton, president and CEO of Global Automakers, an industry lobbying group, agreed, but pointed out that the increased fuel economy standards would lower total ownership costs. "The initial purchase price is growing, but the total cost of ownership is going down, particularly as cars last longer," he said. His concern is that with higher purchase prices, not all consumers would be able to qualify for new car financing, since car loans don't take total ownership costs into account.

Anders Tylman-Mikiewicz, general manager, Volvo Monitoring & Concept Center, U.S., said that Volvo is working to reduce its costs by creating interchangeable platforms for its entire model line. By reusing engines and platforms for different models, Volvo says it will be able to reduce research and development costs and pass those savings on to consumers.

While automakers are working with lighter materials, such as aluminum and carbon fiber, and saving research dollars, they are also developing alternative fuel powertrains to help meet the vehicle standards. Professor Tomasz Wierzbicki, director of MIT's Impact and Crashworthiness Lab, said that the new fuel economy standards are "ambitious, but achievable." Two major factors in helping automakers reach the new CAFE standards, he said, are hybrid and electric cars. However, he pointed out that battery technology can be quite heavy and brings additional safety concerns. Today's lithium-ion batteries, he said, need to be able to "accept more abuse." He said that because there has been no "spectacular accident" in an electric car, the battery industry has been slow to build batteries that can handle being in a crash with little risk for short circuit or fire.

The panelists agreed that meeting the new CAFE standards is possible.  However, the new technology and materials needed to build lightweight, fuel-efficient cars that are safe, will cost more, and those costs will be passed on to consumers. The panel estimated that the new CAFE standards will result in new car price increases of anywhere from $1,800 to $4,000 per model. However, they also agreed that the long-term savings in fuel and other ownership costs should help consumers offset the higher sticker price.

In the market for a fuel-efficient new car? Check out the U.S. News rankings of this year's best cars. Then, look for a great deal on a new car by checking out this month’s best car deals. Also, be sure to follow us on Twitter and Facebook.