Steam has built out a global network over the years to ensure low latency, QoS, and protection from DoS attacks. A recent Steamworks SDK update allows Steam partners to access Steam's internal network so that the partners can leverage the same infrastructure that has made Steam resilient.
Better hurry--you have passengers to pick up and only a handful of seconds to get them to their destination. TaxiCity takes place on the actual streets of Vancouver. The game was created by students using open data and the Bing Maps API.