A simulation study of commuting alternatives for day care centres

Abstract

In Flanders (Belgium), Mobility impaired people need to travel frequently from their homes to a Day Care Centre (DCC). Currently this is done by subsidised bus services but recently a decision was made to cancel these subsidies. The fare the DCC guests will have to pay for transport by bus is too high for most of them. This paper investigates a solution where voluntary drivers bring as many DCC guests as possible to the DCC by carpooling. These drivers can pick up and drop off DCC guests along the way to their work location or any other destination. In general it turns out to be impossible to drive all the DCC guests to the DCC by carpooling. The remaining DCC guests will be picked up by dedicated buses. The goal is to keep the bus travel cost as low as possible. The solution is constrained by car capacities, time windows for both drivers and DCC guests, upper bounds for detours and the availability of intermediate transfer locations. The main challenge is the involvement of multiple transportation service providers. Some of these are not under the control of the consultant in charge of finding an efficient solution for the DCC and hence, their operation and cost cannot be included in the objective function. Solving the problem requires consideration of several cases each leading to a heavy combinatorial computation. Although it seems to be impossible to find a carpool solution in which all the passengers reach the DCC, the results are promising. In several cases four or more chartered buses can be saved on. However, average results show a saving around one to two chartered buses which represents a cost reduction between 20% and 30%.