Since cars are embedded in our way of life, the smartest strategy for reducing pollution is to make the vehicles more environmentally benign and less consuming of road space, says Dan Sperling, director of the Institute of Transportation Studies at UC Davis. Automobiles already account for most travel in developed countries. Even in Japan -- where distances are short, congestion is horrible and rail transit is superb -- autos account for nearly 60 percent of total travel and are increasing their market share quickly. This is good news for the automobile industry, but bad news for those concerned with energy and the environment. Increasing use of autos will exacerbate petroleum supply problems, which may lead to political and economic problems, air pollution and global warming, Sperling says. Because behavior changes (such as switching to car pools and mass transit and living closer to work) are slow, expensive and politically unpopular, technology fixes can have greater impacts and are politically more palatable. Technology fixes include achieving greater fuel efficiency, cleaner alternative fuels, and long-term energy sources based on cleaner technology.