A network approach to trip frequency scheduling for bus routes in heavily congested cities

A minimum cost network flow model is proposed to deal with the problem of bus trip scheduling in heavily congested cities. Real instances of scheduling problems in Bangkok are analysed and solved by means of a particular network formulation. The produced solutions are at least as good as those generated by known procedures. Characterisations which make the network approach superior are very fast solution times, the ease with which the approach can be explained to management, flexibility, and the possibility of doing sensitivity analysis. The modelling technique can be easily extended to situations more complex than a single bus route, and can be useful in less congested urban environments than Bangkok. The approach also illustrates how goal programming principles can be applied in a network model.