The automobile revolutionized transportation and is integral to modern society. But almost from the outset, it also ushered in a range of public health concerns, from car crashes to air pollution to pedestrian fatalities. The lives of Americans are intertwined with the automobile in unexpected ways. Case in point: In the first six months of 2015, the U.S. National Safety Council reported a 14 percent increase in automobile fatalities. The council believes that the increase is due in part to improving economic conditions. Lower gas prices and more jobs meant more people were hitting the road. That, in turn, led to more crowded highways and more crashes.