This paper studies the different public transport networks that can occur after optimisation under different functional scenarios. The question of what an optimal network is has become more relevant, because of the trend to declining public financial support of public transport companies. This may lead to conflicts between the transport companies' objective, to maximise revenues, and policy makers' objectives such as maximising the shift from cars to public transport and maximising the social functions of public transport. The paper formulates the problem of finding the best network as a mathematical optimisation problem, based on a mathematical model. The two main phases of modelling a public transport network modelling a public transport network are: (1) generating a set of lines or routes, and assigning candidates for providing services along them; and (2) assigning optimal frequencies to the services along the lines. The optimisation problem is typically either to maximise total revenue or to minimise total distance travelled by car, subject to a budget constraint and possibly also a social constraint. A case study is presented, that investigates the performance of four optimisation programs that have been executed for the city of Den Bosch in The Netherlands.
Abstract