1. A system for dynamic selection of transit routes, the system comprising: one or more computer readable storage media; a data store contained on the one or more computer readable storage media comprising one or more data structures related to: one or more transit lines in a transit system; a plurality of stop zones served by each of the one or more transit lines; one or more stop options associated with each of the plurality of stop zones; a plurality of stop option weighting factors, wherein each stop option weighting factor describes a relative desirability of a particular stop option in accordance with one or more preference criteria; a plurality of route segment options, wherein each route segment option describes a path between a first stop option and a subsequent stop option; and program instructions for a dispatching service stored on the one or more computer readable storage media that, when executed by a processing system, direct the processing system to: in response to receiving a dynamic route request, wherein the dynamic route request comprises a current location of a particular transit vehicle on a particular transit line, wherein the current location is obtained from a transit vehicle location device, determine a particular transit route from the current location of the particular transit vehicle through one or more remaining stop zones of the particular transit line by: determining one or more remaining route segment options based on the one or more remaining stop zones and the plurality of route segment options in the data store; for each individual route segment of the one or more remaining route segment options: retrieve, from a real-time traffic information service, one or more traffic condition factors related to the individual route segment; determine, from the one or more traffic condition factors, a route segment option weight; calculate a dynamic cost function based on the route segment option weight for the individual route segment, and particular stop option weighting factors for the stop options connected by the individual route segment; and selecting the particular transit route, wherein the particular transit route is comprised of an optimized set of individual route segments, wherein the optimized set of individual route segments is optimized with respect to a totality of dynamic cost functions; and returning the particular transit route to the particular transit vehicle.