Civilization V: Brave New World
In the latest entry of the Civilization V "Enter a Brave New World" video series, Firaxis and 2K Games have detailed the improvements to the more commercial aspects of empire management.
Previous videos have covered culture and tourism and changes to how ideologies work. Today, we're learning more about trade routes and the new units that come with them (caravans and cargo ships). Religion, science, and tourism will flow along trade routes, incentivizing recipient cities to allow the units to pass freely, even if it means a financial boon to the unit owner.
One of the big changes is that trade routes can be established within an empire to funnel food and production to cities that might be low on one or both. This will help speed along growth and completion of build projects.