临界饱和状态交通干线协调控制模型

为提升临界饱和状态下干线车流通行效率，提出了一种基于冲击波理论的干线双向信号协调控制方法。首先，建立了考虑车速变化、转向比例、车道变化等因素的干线交通流模型，分析了临界饱和交通干线交通流运行状态与各参数间的关系。第二，构建了以干线双向通过量最大化为优化目标的混合整数线性规划模型，通过优化干线公共周期和各交叉口绿信比以提高干线通行能力。第三，构建了以延误最小化为优化目标的二次规划模型，并提出了相应的求解算法，通过优化相位差和相位方案实现了干线交叉口的信号协调。临界饱和交通干线协调控制模型由通过量最大化模型和延误最小化模型构成，考虑各交叉口间的制约影响关系，有效避免了排队滞留、溢出、交叉口“死锁”等现象。采用两阶段优化方法，通过通过量最大化模型优化周期及绿信比，继而应用延误最小化模型优化交叉口相位方案及相位差，获得干线系统双向信号协调最优控制方案。最后，应用临界饱和交通状态干线协调控制模型对南京市中山东路10个交叉口进行了信号协调优化，并对优化结果进行了仿真分析。结果表明：临界饱和交通状态干线协调控制模型能对双向临界饱和干线的信号控制方案进行优化，与对照方案相比，优化方案的双向总交通量提升了21.9%，车均延误降低了63.1%，通行能力与服务水平提升显著。

Signal Coordination Control Model for Near Saturated Arterial Intersections

To improve the traffic efficiency of near saturated arterial intersections, a two-way signal coordination control based on shockwave theory was developed. First, an arterial traffic flow model considering factors such as vehicle speed, turning fraction, and lane number was established, and the relationship between the near saturated arterial traffic flow condition and traffic parameters was analyzed. Second, a mixed-integer linear programming model was constructed to maximize the throughput in both arterial directions, in which the cycle length and green split at the arterial intersections were optimized to improve traffic capacity. Third, a quadratic programming model was constructed to minimize the delay and to realize the signal coordination of the arterial intersections by optimizing the offset and phase scheme. A corresponding solution algorithm was developed. The proposed signal coordination control model for near saturated arterial intersections is composed of a throughput maximization model and a delay minimization model. Considering the relationship between restriction and mutual influence between intersections, it can effectively avoid queue retention, queue spillover, and gridlock at intersections. A two-step optimization method was developed for the proposed models. In the first step, the cycle length and green split were optimized using the throughput maximization model. Then, the signal phase schemes and signal offsets were optimized using the delay minimization model. Finally, the signal coordination control model for near saturated arterial intersections was used to coordinate and optimize the signals on East Zhongshan Road, containing 10 intersections, in Nanjing. The optimization results were simulated and analyzed. The simulation results show that the proposed signal coordination control model can optimize the signal control scheme of arterial intersections in a near saturated state. Compared with Gartner's model, the proposed model increases the total traffic volume by 21.9% and decreases the average vehicle delay by 63.1%. In general, both the capacity and the level of service are improved significantly.