Identify the market size of inner-city travel in North America (US and Canada) as well as a breakdown by travel route and by travel mode. Breakdowns should be (1) Total market size for the United States and Canada together (North America), (2) Market size for each major city in both countries with a breakdown by mode of transport, and (3) market size for bus, train, domestic flights, one-way car rentals, and carpool ridesharing in North America. Market Size should be in the volume of trips (number of rides)