Rolling Smokestacks

If you have ever stood on a street corner as a large truck or bus accelerates from a stop, you are acutely aware of diesel pollution. Like passenger cars, trucks have become cleaner since pollution controls were first required in the 1970s. But the degree of cleanup has been a fraction of what regulators have asked of cars. As a result, trucks are now a substantial source of air pollution and other environmental problems. Although trucks account for under 6 percent of the miles driven by highway vehicles in the United States, they are responsible for:

• one-quarter of smog-causing pollution from highway vehicles
• over half the soot from highway vehicles
• the majority of the cancer threat posed by air pollution in some urban areas
• 6 percent of the nation's global warming pollution
• over one-tenth of US oil consumption

Improvements to conventional diesel trucks are an absolute priority, but cleaner alternative fuels and advanced technologies are the ultimate solution.