Washington, USA – Honda and Toyota lead the world’s top eight automakers in lowest greenhouse gas emissions and smog-forming pollution, according to the results of a survey of the auto industry. America’s Big Three – Ford, General Motors and DaimlerChrysler, placed last on the list.



The survey is conducted by the Union of Concerned Scientists, and ranks two factors to determine scores: smog-forming pollution emissions and greenhouse gas emissions. The scores are weighted across models and for the number of each type of car sold.



This is the fourth time in a row Honda has topped the list, but Toyota came within one point of tying for the lead. Hyundai-Kia, Nissan and Volkswagen ranked third, fourth and fifth, respectively, and the American automakers Ford, G.M. and DaimlerChrysler placed sixth, seventh and eighth.



“There is a huge gap between the cleanest and dirtiest automakers,” said Don MacKenzie, author of the report and a vehicles engineer with UCS. “The winners are using clean technology across their entire fleets. The losers are installing it piecemeal, or not at all.”



The automakers surveyed make up 96 percent of the total U.S. car and light truck market for the model year 2005, the latest for which full data is available. MacKenzie expects to see a significant shift in the next such survey, which will take into account the explosive demand of hybrids like Toyota’s Prius as well as the increasing fuel-economy awareness of American drivers in the post-Hurricane Katrina era.



In analyzing the results, MacKenzie said that consistency in adopting clean technologies is what makes the leading companies stand out. Honda and Toyota especially had better-than-average scores on GHG emissions across all car classes, and even though Toyota sells a substantial amount of SUVs and pickups, its embrace of emissions-cutting technologies kept it competitive with Honda.



Meanwhile, even though Ford began selling its own SUV hybrid, that small advance was more than wiped out by its reliance on – and the popularity of – its heavy trucks and SUVs.



“Any company can build one green model, but what counts is when a co makes all its models or its most popular models green,” MacKenzie said. Two examples he offered were Toyota’s Prius, which is both immensely popular and very clean, and the Hyundai Elantra, by far the Korean automaker’s cleanest and most popular car.



Another aspect of the consistency argument, MacKenzie said, is that automakers can surge ahead on this list by being consistent globally as well as within markets. He said that in the U.S., Ford was the cleanest of the Big Three automakers, although still placing toward the bottom of the list. However, in Europe, Ford is one of only five companies to meet the E.U.’s voluntary global warming targets. “If they’d made the same cuts here that they’d done in Europe starting in 1997, it would have tied for 3rd in the rankings,” MacKenzie said.



Implementing hybrid technologies, or using flex-fuel vehicles that can run on biodiesel and ethanol, is not the only, or even the best, strategy for wide cuts in emissions. Under-the-hood technologies that drivers might not even recognize can also have significant impacts on performance and emissions. Nissan, for example, uses continuously variable transmissions in many of its cars, many automakers are adopting six-speed transmissions, and G.M. and Honda both use cylinder deactivation technologies to improve performance.



MacKenzie said, “Some of these things – improving transmissions, improving engines, improving aerodynamics – these are all little things that automakers can do to help improve the performance of their vehicles.”



“All of the automakers have the technology today to make all of their vehicles, from two-seaters to four-by-fours, a lot cleaner,” MacKenzie added. “And given the Supreme Court ruling confirming carbon dioxide and other global warming emissions are pollutants, it’s likely that federal or state efforts will succeed in requiring automakers to put that technology to work.”



The Union of Concerned Scientists expects to see a dramatic shift in results when it releases its next report in roughly two years. Not only will that survey find newer technologies in wider use, but with the advent of the $3 gallon of gasoline, and concern about global warming on the rise, drivers’ tastes are changing.



“Americans are paying closer attention to their personal environmental impact, and they want greener cars,” said Ted Grozier, an associate at the environmental strategy consulting firm GreenOrder. “The successful automaker is going to figure out a way to deliver those cars to consumers.”



The full report is available from the Union of Concerned Scientists.