Winter 2010-2011

Close To Home | Whose Cars Are Greenest?

Eight automakers account for more than 90 percent of all cars and trucks sold in the United States. A growing number of these automakers’ ads tout their concern for the environment, but many of these assertions ring hollow given the results of our Automaker Rankings 2010 report, which uses government data to evaluate the environmental performance of each of the top-selling automakers. We assessed each manufacturer based on the smog-forming and global warming emissions of its entire vehicle fleet for model year 2008—the latest year for which data were available.

How the Automakers Stack Up

For the fifth consecutive time over the past 10 years, Honda claimed our Greenest Automaker award, this time narrowly beating out Toyota and Hyundai (which tied for second place). At the other end of the spectrum are the Detroit Three—Ford, General Motors, and Chrysler—which have shared the lowest slots in all five of our assessments due to their higher-than-average pollution levels. Volkswagen and Nissan round out the rankings in fourth and fifth place, respectively.

Automakers’ efforts—or lack thereof—to improve their products had a major impact on the final rankings. Toyota, buoyed by its strong gasoline-electric hybrids, could have overtaken Honda as the greenest automaker if it had made even modest fuel economy improvements to its conventional vehicle fleet. Conversely, without the Prius (the cleanest and best-selling hybrid on the market today), Toyota would have finished fourth.

Volkswagen benefited from its decision to drop diesel vehicles from its model year 2008 U.S. offerings in order to help meet tailpipe emissions regulations.
Today’s diesels provide better fuel economy (and thus lower global warming emissions) than comparable gasoline-powered vehicles, but typically generate more smog-forming emissions; in Volkswagen’s case, a diesel-free fleet helped improve the automaker’s overall score.

Lessons Learned

Sales matter. Fairly mundane improvements to the engines and transmissions of all vehicles can have a much larger impact on the environment than offering the most advanced technologies in only a few vehicles.

Consistency is key. The top-ranking automakers deliver best- or near-best-in-class performance, both on smog and global warming, in all or most of the vehicle classes in which they compete.

Full lines can compete. Top-ranked Honda and Toyota both produced vehicles in seven of the eight classes considered in our report (including pickups and SUVs), and Hyundai competed in six of the eight classes. Clearly, an automaker’s claim to the crown does not depend solely on production of small cars.

Standards work. Today’s cars and trucks pollute less than those made just five years ago thanks to policies that required automakers to clean up their products. As new standards are phased in over the coming years—including groundbreaking fuel economy and global warming emissions regulations that UCS helped secure—we expect the gap between the cleanest and dirtiest automakers to narrow even further.


Also in this issue of Earthwise:


What are the risks of extracting natural gas by means of hydraulic fracturing (“fracking”)?