With increased urban density comes worsening traffic congestion that can paralyze mobility, harming air quality, economic productivity, and stress levels. To combat traffic, New York City is expanding its public bike-share system, boosting investment in the long-neglected subway system, and imposing a surcharge on ride-hailing services, among other steps. Other cities have adopted congestion pricing. And futuristic solutions range from flying taxis to vast networks of tunnels. But, writing in the Wall Street Journal, CGEP Director Jason Bordoff argues that a more humdrum transportation option is poised to transform urban mobility: the bus.