Waze, the world’s largest navigation app, uses real time crowdsourced traffic data to calculate the most time, and fuel, efficient driving routes for its users. But these data are now having a powerful impact on city infrastructure. In her recent talk, Waze’s Thais Blumenthal de Moraes outlines the Waze Connected Citizens Program. Currently over 250 cities worldwide partake in this free data exchange with Waze, consequently gaining insights which can inform appropriate planning solutions to specific problems. For example, Boston used Waze data to adjust its traffic signal timings, resulting in an 18% reduction in congestion month over month.