Granular transport policy

Abstract

The present situation in transport policy is that many authorities have a responsibility for a part of the transport system and that each authority has its own goals and priorities. Central steering is only on main policy goals. Public transport and municipal, regional, provincial and national road authorities have their own policies, targets and instruments. The interaction between different policies themselves exists indirectly, but policies are 'granular'. In this paper the granular transport policies are described as a game with many players. Integrated traffic control and traffic assignment problem are studied for a situation with two road authorities. The road authorities try to optimize their own objectives and the same is done by the travelers. This leads to a two-level three-player, multi-stage optimization problem with complete information. Game theory gives a suitable framework to analyze the problem and to find solutions for different situations, e.g. no cooperation, cooperation between the two authorities and a system optimum where all actors cooperate to minimize the total costs for all travellers. In this paper two approached are used: an analytical one and an approach based on a simulation and assignment framework. Both approaches are described and used to study a simple example, for which the results are given and discussed. The results show that separate or integrated anticipatory control gives better results than iterative reacting to the current situation. If one road authority takes the lead and anticipates the reactions of both the road users and the other road authority a sub-optimum is reached. The model calculations give evidence that cooperation of road authorities improves the utilization of the infrastructure and that a global optimization does not necessarily give a worse situation for one road authority.