The percentage of 16-year-olds with a U.S. driver’s license has decreased sharply in the last decade, from 43.8 percent in 1998 to 29.8 percent in 2006. Rising insurance costs, expensive driver education, and an increase in indoor pastimes are more likely to be driving the trend than environmental awareness — and sure, most yoots still get around in four-wheeled transportation, chaffeured by parents and friends. But at the very least, we suspect that fewer kids with a license means fewer cars idling for hours while teens grope in the back.