Two-way communication between a mobile device and a server is used to provide increased relevance of traffic information at lower bandwidth. The complexity, amount of storage and processing power required of the mobile navigation device are minimized, since the server performs much of the required computing. A transactional billing model can be used to bill the driver based on usage or consumption of traffic information. A driver selects a destination and routing preferences on a mobile device, and the local system generates a routing. The mobile device sends the planned route and preferences to a server. The server uses real-time traffic flow and incident information to determine an estimated driving time for the planned route. The server may also generate alternative routes, with an estimated time for each alternative route. The traffic and time information for the planned and alternative routes are then transmitted back to the mobile device.