Numerous smart-city schemes have run into delays, dialed down their ambitious goals, or priced out everyone except the super-wealthy. A new project in Toronto, called Quayside, is hoping to change that pattern of failures by rethinking an urban neighborhood from the ground up and rebuilding it around the latest digital technologies. One of the project’s goals is to base decisions about design, policy, and technology on information from an extensive network of sensors that gather data on everything from air quality to noise levels to people’s activities. All vehicles are to be autonomous and shared. Robots will roam underground doing menial chores like delivering the mail. Sidewalk Labs says it will open access to the software and systems it’s creating so other companies can build services on top of them, much as people build apps for mobile phones. The smart citiy could make urban areas more affordable, livable, and environmentally friendly.