Text Size AAA Bookmark and Share

Battling America’s Automotive Obesity Epidemic

By Greg Rucks

Americans face an obesity epidemic of staggering proportions: nearly 36 percent of U.S. adults are considered obese, according to the Centers for Disease Control and Prevention, up from 12 percent in 1990 and 23 percent in 2005. That obesity epidemic has been fueled in no small way by an addiction to liquid fuel, in particular the sugary empty calories of soda. Last year Americans’ soda consumption averaged more than 467 12-ounce cans per person, according to data from Beverage Digest.

Our cars have followed a similar trajectory. In the past quarter century the average weight of new cars has ballooned by nearly 25 percent, growing from 3,221 pounds in 1987 to 4,009 pounds in 2010. In percentage terms, cars gained weight twice as fast as we did. And their parallel addiction to liquid fuel—oil—is enormous. Autos alone account for half of U.S. oil use, to the tune of 8.8 million barrels per day.

With stronger new fuel economy standards, that trend should start to slow or even reverse. But if we’re serious about getting the U.S. transportation system off oil sooner than later, more drastic action is necessary.


America’s oil dependence seemingly costs $2 billion per day, but actually costs upwards of three times that much—$6 billion per day, or a sixth of GDP. That’s due to three kinds of hidden costs, each about a half-trillion dollars per year: the macroeconomic costs of oil dependence, the microeconomic costs of oil-price volatility, and the military costs of forces whose primary mission is intervention in the Persian Gulf. Yet RMI’s analysis shows that transitioning America’s transportation system completely off oil could save $3.8 trillion in net present value between now and 2050—or nearer $12 trillion if we counted those hidden economic and military costs.

That strong economic incentive is just the beginning. Our oil addiction’s real costs to health, safety, environment, security of energy supply, global development and stability, and national reputation are extra. With atmospheric CO2 levels over 400 ppm for the first time in human history—and enormous environmental and human health impacts from oil exploration, consumption, and emissions—ending oil addiction is imperative for reasons that extend well beyond just saving fuel costs. But how do we do that?


Succeeding in the monumental task of transitioning the entire U.S. transportation system off oil starts with a seemingly straightforward but important first step: focus on automobiles. The sheer size of the U.S. automotive industry means that efficient technologies adopted for autos can quickly impact a wide swath of the market, with a strong ripple effect that propagates through the other interdependent arms of the transportation industry, including heavy trucks, airplanes, trains, and ships.

Getting cars off oil requires two fundamental shifts: 1) dramatically increase their fuel efficiency, and 2) as we’re already starting to see with EVs, electrify their powertrains. Both of those shifts are ultimately dependent on an incredibly influential driving factor: vehicle weight, which causes two-thirds of autos’ fuel use.

Lightweighting autos can coax maximum efficiency out of our reimagined cars of the future and enable powertrains that take full advantage of the more efficient and higher-performing characteristics of electric drive. For such revolutionary cars to achieve their fullest potential, we need to take a “clean sheet” design approach, reimagining the vehicle from scratch.

All of this depends on a key driver: advanced lightweight materials. That’s because higher-performing materials enable groundbreaking designs and smaller, more efficient, and cheaper electric powertrains that deliver higher performance with fewer batteries.

Carbon fiber composites quickly emerge as the preeminent advanced lightweight material to do this. It offers unparalleled potential to produce ultralight, ultrastrong cars while maintaining or exceeding vehicle safety, robustness, and performance standards and expectations.


If carbon fiber is so great, why hasn’t it been adopted already?

To some degree it has, though mainly in niche markets for high-end, small-production-run sports and luxury cars. For example, you’ll find carbon fiber in the hood and roof of the BMW M3, the A-pillar of the Aston Martin Vanquish, and the floor and bulkhead panels on the 2014 C7 Corvette. Carbon fiber has also started to trickle into other makes and models. VW is developing a carbon fiber roof option (explicitly designed to shave weight and improve fuel economy) for the performance version of its Golf. And Toyota, after shutting down production on its carbon-fiber-based Lexus LFA supercar, may start incorporating carbon fiber parts into other models.

Then there’s Volkswagen’s XL1, which achieves the astounding efficiency of 230 mpge through lightweight structure enabled by carbon fiber construction along with very good aerodynamics and low rolling resistance. But the initial run will produce only 250 vehicles priced at a hefty $130,000 each. BMW’s i3, starting at midvolume production (rising quickly to 30,000+ vehicles per year) and priced at around $40,000 euros, better illustrates determination to bring carbon fiber electric cars into the mainstream.

These examples demonstrate the Achilles heel of carbon fiber autos to date—low- to mid-volume production at fairly high cost. Making carbon fiber structures more cost effective and widely adopted across high-volume, mainstream autos is the next challenge. That’s where RMI comes in.


In November 2012, RMI hosted a three-day workshop in the Detroit area with about 45 leading experts from across the automotive carbon fiber composite value chain, industry experts, and government representatives. We convened to develop ways to break down the barriers that have stifled advancements in lightweighting autos. Overcoming those barriers would permit the widespread penetration of carbon fiber composite into mainstream vehicles.

Two related strategies soon came to the forefront: a parts campaign and an innovation hub.

Starting with a campaign for individual parts would be a high-leverage pathway to eventual high-volume production. For example, just one high-volume carbon fiber part on four mainstream vehicles would double total worldwide demand for carbon fiber, creating strong pressure to streamline processes, increase innovation, spur competition, optimize supply chains, and prompt adoption. Workshop participants identified and rigorously evaluated three promising parts that offered both a financially attractive and technically viable near-term business case: the door inner, the engine cradle, and the seat back.

Meanwhile, an innovation hub based in Detroit or elsewhere would facilitate knowledge sharing and provide access to shared test rigs and manufacturing equipment. It would foster collaboration among automakers, their supply chains, government, advanced tooling manufacturers, and industry experts. Such “coopetition” will be necessary to spur industry adoption of carbon fiber beyond small-scale, niche applications.

Now, RMI is focused full speed ahead on a discrete parts campaign to incorporate a carbon fiber composite part targeted on a circa Model Year 2018 vehicle with a production capacity in excess of 50,000 units per year. This alone will save 5.2 million gallons of fuel per year and 47,000 metric tons of annual CO2 emissions. But more importantly, it will break open the market for automotive carbon fiber, starting the U.S.—and the world—on a more concrete path to ending our automotive obesity epidemic and thirsty addiction to oil.

For more information, read RMI’s report Kickstarting the Widespread Adoption of Automotive Carbon Fiber Composites.

Greg Rucks is a senior consultant for RMI.


Assembly line image courtesy of Shutterstock.
M3 image copyright BMW AG.
XL1 image copyright Volkswagen.
Corvette image copyright General Motors.

Show Subscribe