We pay a stiff price for our car addiction. Daniel Roos starts with the plight of American auto manufacturers, whose market share is dropping and whose plants close as foreign makers move to the U.S. They are victims of their own overproduction. Roos recommends a build-to-order system to reduce inefficiencies. What happens when too many people drive too many cars? The Chinese, recent converts to combustion, boast 24 million vehicles and a tragic, new statistic: 107 thousand auto fatalities, more than twice as many as in the U.S. Some measures for car-clotted areas may be high occupancy toll lanes (aka Lexus Lanes), where solo drivers pay more for less trafficked roads; fees for entering densely traveled urban areas; and computer-run, intelligent transportation systems.While "too many of us use too much stuff too often," says John Heywood, cars may prove the worst commodity of all. They are responsible for a steady degradation of the ecosystem, from greenhouse emissions to biodiversity loss. What's worse, even if we improve vehicle efficiency, turn to fuel hybrids such as the Prius, or make rapid advances in hydrogen-based fuel technologies, the scale for slowing down the degradation may run to the decades. We have 130 million cars on U.S. roads right now, and add 15 million more each year. "Turning the curve won't be easy," says Heywood. "Human beings simply won't do as much as they can." Recommendations: an integrated policy approach, including better mileage standards and a stiff gasoline tax.