Improving Energy Efficiency of Public Transport Bus Services by Using Multiple Vehicle Types

Abstract

Public transport can provide an environmentally friendly transportation alternative to private cars. However, resources are not always used optimally, and the efficiency of operation might be improved by altering timetables and vehicle schedules. A case in which multiple vehicle types were inserted into even-headway timetables was developed and examined for better balancing of the fluctuations of passenger loads. This examination focused on the benefits derived in energy efficiency on top of other advantages. A multiobjective optimization was used to determine timetables that would minimize both total passengers’ waiting time and total empty-seat minutes on the vehicles. Sets of these Pareto-optimal timetables were then used to determine optimal vehicle schedules for the vehicle types used. The methodology was applied to a real-life case study from Auckland, New Zealand. Results showed that timetables with multiple vehicle types could increase passenger occupancy of the vehicles by 19% and thus could reduce total energy consumption. These results were attained without any increase of the total passenger waiting time and fleet size.