My neighbor Lisa’s minivan, a pearly blue 2008 Chrysler Town & Country, has a hundred and eighty-four thousand miles on it, reflecting the fact that in a car-centric city like Austin, Texas, to be a parent is also to be a part-time shuttle driver. She’s racked up miles driving the boys to and from school—not to mention Scout meetings, band camp, wrestling tournaments, and her older son’s first date. She also ferries them on summer cross-country road trips lasting many weeks. (Her husband, who works at I.B.M., joins them for shorter segments along the way.) In 2014, she took things a step further by obtaining a commercial driver’s license, so that she could operate a rig full of equipment for the high-school marching band. Then, last year, she went pro: she started driving for Uber and Lyft.