Our outdoor spaces are changing fast. Sidewalks now have pedestrian and electric scooter traffic. Small delivery drones drive alongside cars and trucks. Smart cameras and sensors are being used to detect how we’re moving around our cities, and artificial intelligence systems can produce digital twins of city blocks to pressure-test changes to traffic flow, population increases and public events. For example, Strava Metro is using the data from runners and cyclists to help urban planners design safer streets.