Design of Short-Turning Service for a Bus Route with Hybrid Vehicle Type

On the high-demand bus route where there are commuting passengers, the stops for boarding and alighting passengers are concentrated in a certain section of the route. According to this demand pattern, transit operators need to respond symmetrically. Short-turning services promise benefits for both users and operators because a proportion of vehicles runs within shorter cycles and address a greater demand. The design of short-turning services mainly involves defining running section and frequency. Due to two sections of high and low demand being distinguished under the short-turning service, dealing with each section by vehicle type and selecting an appropriate vehicle type for each section can satisfy passengers demand well, instead of a single vehicle type. Considering the interests of passengers and buses, this paper establishes objective functions to determine the running section of short-turning buses by frequencies and vehicle types. Two optimization models with single and hybrid vehicle type are formulated that can be compared with each other and reflect the differences of method with hybrid vehicle type. Load factor is established as a performance measure to express the degree of utilization of bus resources. A layer-by-layer search method incorporating Monte Carlo simulation is proposed to solve the optimization model. Finally, the optimization approach is tested based on a bus route in Changchun City. Sensitivity analyses are then performed on the passenger demand and travel time