A Two-stage Model for a Day-ahead Paratransit Planning Problem

Abstract We consider a dynamic planning problem for the transport of elderly and disabled people. In particular, we focus on a decision to take one day ahead: which requests should be served with own vehicles, and which requests should be subcontracted to taxis? We call this problem the Day-ahead Paratransit Planning problem (DaPP). The model developed for DaPP is a non-standard two-stage integer recourse model from stochastic programming. Both stages consist of two parts: requests are first clustered into routes, and these routes are in turn assigned to vehicles (own vehicles and taxis). To solve this model, a genetic algorithm approach is used. Computational results are presented for randomly generated data sets.