Multiple paths through a network

The most sophisticated iterative algorithm for balancing network congestion for a given set of desired vehicle movement from origins to destinations can generate thousands of paths of equal cost to connect a single O-D pair. Some sets of paths are combinations of minor variations on one main path, while other sets contain various degrees of difference, possibly up to complete independence. Present methods for comparing paths do not take into account the multi-dimensional nature of similarities and differences between paths, or the different character of sets of paths - especially from a geographic point of view. I develop a battery of methods of making comparisons, and apply them to illustrative sets of paths identified in the highly disaggregated Chicago network. I begin a discussion of how these comparisons might be used to throw light on problems of network aggregation and of discrete choice of route among populations of users.