Making clean, green auto machines seems to have eluded Detroit's Big Three carmakers as five of their foreign counterparts come in ahead of them in the Union of Concerned Scientists' (UCS) biennial ranking of the greenest automakers.
Of the eight top companies making cars in the U.S., the leader of the pack was Honda, for the fourth consecutive time, with Toyota coming in a close second; Hyundai-Kia, Nissan and Volkswagen were third, fourth and fifth; bringing up the rear were Ford and General Motors at sixth and seventh, with DaimlerChrysler dragging its tailpipe in last place, earning the car company the Rusty Tailpipe Award for the dirtiest automaker.
"There is a huge gap between the cleanest and dirtiest automakers," said Don MacKenzie, a vehicles engineer with UCS and the author of the report, Automaker Rankings 2007: The Environmental Performance of Car Companies. "The winners are using clean technology across their entire fleets. The losers are installing it piecemeal, or not at all."
Each automaker was rated on how its vehicles compared to the industry average on global warming and smog-forming pollution. Cars and light trucks account for 25 percent of the nation's global warming pollution and 20 percent of its smog-forming pollution.
According to Mackenzie all the automakers have the technology to make all their vehicles a lot cleaner. He believes that it will take federal or state mandates to require automakers to use that technology to make cars that meet pollution emission requirements.
Although Ford, at sixth, was the cleanest of the Big 3 automakers, if they had made the same progress cutting global warming pollution in its U.S. fleet as it has with its European fleet, Ford would have finished in fifth, the report noted.
GM, which placed last in UCS's 2003 model rankings, was able to move past DaimlerChrysler in this year's rankings by reducing its fleet's smog-forming emissions.
Still, the country's biggest automaker was not able to improve its global warming pollution score since the last UCS automaker rankings. In model year 2005, GM had the dubious distinction of selling the most vehicles rated at 15 miles per gallon or worse in city driving, statistics showed.
And how did DaimlerChrysler manage to come in last with the the worst scores for both smog and global warming pollution? By producing cars and trucks that emit 70 percent more smog-forming pollutants and nearly 30 percent more global warming pollutants per mile than those made by Honda.
The UCS analysis showed hybrids helped improve environmental performance while diesels generally held automakers back. Volkswagen's diesel engines slightly improved its global warming score, but significantly dragged down its smog score.
Hybrids, meanwhile, helped Toyota cut its global warming pollution fleetwide because the company produced them in large numbers. Honda and Ford, which produced fewer hybrids, did not see the same improvement.