Optimization Of Integrated Scheduling Plan Considering Bus Emissions

The idea of corporate social responsibility has promoted bus operation agencies to rethink how to provide not only efficient but also environment-friendly services for residents.Short-turn service allows buses to serve shorter cycles with high demand to save passengers' waiting time and emissions.In addition,some stops with low demand can be skipped in the express service,which reduces passengers' in-vehicle time and emissions by optimizing operating conditions of buses.Accordingly,a study on optimized design of the integration of all-stop services,short-turn services,and skip-stop services is conducted in this thesis.First,two integrated service patterns considering all-stop services,short-turn services,and skip-stop services are designed.On this basis,the methods to estimate bus emissions and OD(Origin and Destination)distribution of passengers are proposed.The operation process of buses is divided into short trips.The emissions of each trip are estimated using the emission factor measurement method based on Vehicle Specific Power.Thus,emissons of the two integrated services can be obtained.Besides,the OD distributions of passengers in the two integrated service patterns are estimated.Based on the current passenger demand,the OD demands with different traffic modes are calculated via the modelling of passenger choice behavior along the route with integrated services.Secondly,two models for optimal integrated scheduling are developed to minimize the total costs of passengers,operating agencies,and bus emissions in different service patterns.The focuses of the models are to determine the optimal bus frequencies,the skipped stops for express service and turn back points for short-turn service.The constraints,including the load factor,headway,fleet size in operations,are considered in the models.Then,a solution method based on genetic algorithm is developed to solve the problem.Finally,a real-world case of typical route in Beijing is studied,in which the optimal scheduling strategies that maximize the cost savings of passengers,operators,and environmental agencies are determined.The costs of the proposed scheduling strategies under the two integrated service patterns are compared with the existing situation.The results show that,compared with the scheduling strategy with all-stop services,the scheduling strategy under integrated service pattern 2 has more advantage in the reduction of total costs than pattern 1.Furthermore,sensitivity studies are conducted to investigate the impact of passenger demand and fleet size in operations on the effectiveness of the proposed strategies.The sensitivity results have verified the stability and applicability of the proposed model.The study provides a new perspective to develop an ecological scheduling pattern and optimal strategy that aims to improve the service quality,lower operating costs,and reduce emissions for public transportation agencies.