Hierarchical Multi-objective Model for Arterial Dedicated Bus Speed Optimization

In order to solve the problems of strong multi-factor linkage constraints and poor overall effect in arterial bus speed guidance, this paper proposes a hierarchical multi-objective speed guidance optimization model. A multiobjective optimization framework is designed to maximize the punctuality rate as the first-priority objective while the number of stops at intersections and the consistency of speed taking as the secondary objectives. With the associated constraints and priority among the multiple objectives, a hierarchical multi- objective decision- making approach is constructed by a combination of the Lagrangian multiplier method and genetic algorithm. Finally, an experiment based on actual scenarios is adopted to verify the effectiveness of the proposed model. The experiment results show that the model can guarantee the improvement of multiple performance indexes. It increases the overall punctuality rate from 69.67% to 90.53% and decreases the number of stops at intersections from 2.37 to 1.23 for each bus. Compared with the non-hierarchical multi-objective optimization method, the overall punctuality rate is improved by 8.65% in this hierarchical optimization method. The hierarchical optimization method provides the priority of the overall punctuality rate, and effectively improve the traffic efficiency and service reliability of dedicated buses.