车路协同环境下重叠线路公交车速诱导策略

为了防止公交车辆在线路重叠运行区间产生公交串车，在站点附近形成交通瓶颈，提出一种采用车速诱导策略来调整公交运行状态的动态调度模型。采用车路协同环境下的公交运营调度方式，结合各线路独自运行时的乘客需求和车辆车头时距规律，在避免重叠区站点公交串车的前提下，实现了各线路车辆最大程度地维持各自独立运行时车头时距的优化目标。提出的车路协同环境下的车速诱导调度策略，在引导各线路公交车辆间隔均匀地进入重叠区间后，根据乘客实时交通需求和道路交通状况，实现对车辆的实时调控。开发了一种启发式算法对车辆进入重叠区间的时刻进行求解，采用基于遗传算法的仿真过程求解了重叠区站点之间车辆的最佳运行速度，实现了重叠区间车辆动态调度过程。以哈尔滨市运行区间重叠的3条公交线路为实际案例进行仿真分析，对3条线路共计47辆公交车在重叠区12个站点之间的运行状况进行了优化调度。结果表明：采用提出的启发式算法进行调度后，车辆可以完全均匀地进入重叠区。通过对比采用动态调度优化前后的车辆运行状态发现，车辆串车现象由优化前的单站最多发生6次下降为0次，最大程度地实现了避免公交串车的目标。此外，车速诱导策略不仅避免了不同线路车辆在重叠区站点的串车现象，而且可以调整各线路上相邻两车之间的车头时距偏差，线路1的车头时距最大偏差从55%下降到了30%，线路2的车头时距最大偏差从25%下降到了13%，线路3的车头时距最大偏差从23%下降到了18%。

Speed Guidance Strategy for Buses Run on Overlapping Route Segments Under Cooperative Vehicle Infrastructure

To prevent bus bunching and traffic bottlenecks near stops in overlapping route segments, a dynamic dispatching model was proposed. The model used a speed guidance strategy to adjust the operation status of the bus. Considering the passenger demand and bus headway when each line was operating independently, the bus operation dispatching method was adopted under a cooperative vehicle infrastructure (CVI) environment. To achieve the optimization objectives, the buses on each line can be maintained in the headway of the lines and avoid bus bunching at the stops in the overlapping route segments as much as possible. The proposed speed guidance dispatching strategy in the CVI environment guides the buses of each line to enter the overlapping segments smoothly and realize real-time control of the bus according to the real-time passenger demand and road traffic conditions. A heuristic algorithm was developed to calculate the bus entry time for overlapping route segments, and a genetic algorithm (GA) was used to determine the optimal speed of the buses between stops in the overlapping route segments. The dynamic scheduling process of the bus in overlapping route segments was realized. Three overlapping bus lines in the operation section of Harbin City were considered for a real case simulation analysis. The operation status for a total of 47 buses on the three lines between 12 stops in the overlapping route segment was optimized and dispatched. The results show that after using the proposed heuristic algorithm, buses could enter the overlapping segment evenly. By comparing the running state of buses before and after the optimization of dynamic scheduling, the phenomenon of bus bunching was found to have decreased from a maximum of six in a single stop to zero, which achieved the goal of avoiding bus bunching to the greatest extent. In addition, the speed guidance strategy not only avoids bus bunching on different lines in the overlapping route segments but also adjusts the headway deviation between adjacent buses on each line. The maximum headway deviation of line 1 was reduced from 55% to 30%. The maximum headway deviation of line 2 dropped from 25% to 13%. The maximum headway deviation of line 3 dropped from 23% to 18%.