The first U.S. city to host a docked bike-share system, Washington, D.C., is now home to a rapidly growing influx of dockless bikes, with five companies vying for the market. The docked system still accounts for 87 percent of the shared bikes in the United States, but the number of dockless bikes—which can be located by riders using an app and then left anywhere—is growing rapidly. The data from these location-enabled bikes provide a unique opportunity to measure the point-to-point transportation needs of millions of people in some of the world’s densest cities.