Minimizing electricity consumption in a personal rapid transit transportation system

ABSTRACT In this study, we address the minimisation of the consumed electric energy in a personal rapid transit transportation system (PRT). The PRT system can play a significant role in the supply chain, especially in the last mile delivery of goods in urban areas. Instead of transporting passengers and goods on different vehicles, the capacities offered by PRT system can be consolidated and utilised in a shared mode. Two compact formulations of polynomial size are developed for sequencing the vehicle trips. Since the existing model from the literature performed poorly, the first and the second models are developed by applying the lifting technique and Reformulation-Linearisation Technique, respectively. These techniques are well known for strengthening existing models whose linear relaxation is weak. In addition, we embed strengthened cuts within a constraint generation solution procedure. The performance of the proposed formulations is verified through computational experiments conducted on some instances from the literature. Furthermore, optimal solutions are provided for all the unsolved instances.