时空维度下城市地面公交系统双目标评价方法

Spatiotemporal Bi-objective Evaluation Method for Urban Bus Systems

为量化评价公交运营中广泛存在的供需时空分布不平衡、车辆空驶导致道路时空资源浪费等现象,基于对人、车、路间相互作用的解析,提出了时空维度下的城市地面公交系统双目标评价方法。评价体系主要由供需时空匹配指数及时空资源占用指数构成。其中,供需时空匹配指数可以直观刻画出行需求与运能供给的匹配程度;时空资源占用指数可用于衡量公交系统运营中对道路时空资源的人均占用情况。基于公交GPS数据和IC卡数据等进行评价指标的计算,选择上海市4条不同特征的公交线路进行实例分析,并根据指数实际计算结果的累积频率曲线标定了双目标评价体系的分级阈值。分析结果表明,提出的双目标评价方法能够为公交系统的基础设施建设及后评价、车型配置及发车计划等调度方案的制定提供科学有效的参考依据。

The mismatching of supply and demand in bus systems in the space-time dimension leads to the waste of spatiotemporal resources as near-empty buses are still running according to schedules,especially during off-peak hours.In order to quantify the above problems,a bi-objective evaluation method was built upon the investigation of the interactions among passengers,buses,and road resources.The evaluation system consists of two indexes,the supply-demand matching index(SDMI)and the space-time occupancy index(STOI).The SDMI quantifies the matching degree of travel demand and bus line capacity,while the STOI measures the per capita occupancy of spatiotemporal resources in bus operation.The calculation of the SDMI and STOI were based on the global positioning system(GPS)data and the integrated circuit(IC)card transaction data,etc.Finally,four bus lines with different characteristics in Shanghai were used for case study.Considering the actual distribution of the two indexes,the classification thresholds of the bi-objective evaluation system were identified according to the cumulative frequency curve of the SDMI and STOI.The proposed method can be further utilized in the evaluation of public transit infrastructures and the optimization of bus type selection and bus scheduling,etc.