Opening transportation data can improve cities in several ways:
Transportation - More people may prefer public transit over cars if open data leads to apps showing arrival times and delays, reducing traffic.
Environment - Less car usage may decrease carbon emissions and air pollution.
Economics - New apps and services based on open data can create jobs and commercial opportunities.
The document discusses examples of open transportation data portals and apps in cities like Saint Petersburg and New York, and argues governments should publish more of their transportation data to encourage innovation. Opening just 1% of local government data on areas like transportation could help cities and save public money.