Applying Inter Regional Shared Routes in Detailed Multiregional Dynamic Traffic Models
M P H Raadsen, M P Schilpzand, E Mein, OmniTRANS International, NL
In recent years, dynamic traffic assignment (DTA) models are applied more and more on large-scale real-world networks. Thereby the complexity of the DTA models has increased to the point that maintaining routes between all zone-pairs is now an inefficient use of computing resources. Several models have been introduced that are based on the usage of splitting rates at bifurcation nodes at the cost of losing route information. This paper presents an innovative approach to model routes in large dynamic traffic models (e.g. 4000+ zones) using the well-known analogy of conduits in fluid dynamics.
Within detailed multiregional models, a large subset of routes between two regions will contain a significant segment of their routes in common. Binding all routes on this segment together in a single sub-route can significantly reduce the amount of resources required. Multiple catchment areas are defined that are connected by several bound routes, reflecting interregional route choice. Using this approach, original route information is preserved up to the point where the destination catchment area is reached. Some, manageable, loss of information will occur when entering the destination catchment, since from that point splitting rates are used. Thus, the algorithm aims at combining the best of both worlds; optimizing performance while at the same time keeping track of as much route information as possible
The algorithm is implemented and analysed in an existing DTA framework and compared with approaches using routes and splitting rates respectively. Results using this approach are far better compared to splitting rates based models and arguably inferior to keeping track of all routes at all time.
Association for European Transport