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Rule-based and optimization-based autonomous intersection management (AIM) policies have been evaluated against traditional signal controls in terms of intersection safety, efficiency and emission. As one of AIM policies, reservation-based control has further taken advantage of the benefits of AIM, especially via optimization approaches. This paper presents a time-independent trajectory optimization approach for connected and autonomous vehicles under reservation-based intersection control. The existing approaches assign an arrival time and speed to vehicles ahead of entering the intersection. However, the vehicles may not follow the planned trajectory once the traffic condition varies sharply and thus the trajectory solution becomes infeasible with respect to the assigned arrival time and speed. The proposed approach aims to solve the fail-follow problem by separating the optimization between arrival time, speed, and trajectory planning by optimizing the trajectory without arrival time and speed predetermined. The approach finds the optimal solution in terms of the intersection efficiency meanwhile keeps the feasibility of trajectory planning by formulating the variation of acceleration rate and breaking a whole trajectory into an enlarged set of segments. Two different control strategies, BATCH and ZONE, are also proposed to test the performance of the optimization approach in comparison with another Dynamic Batch strategy. The results validate that the proposed approach can adapt to extremely high traffic demand scenario. Sensitivity analyses also evaluate the performance of the proposed approach under different problem settings in terms of intersection efficiency.

With the rapid development of urbanization and motorization, the proportion of the passenger cars is high, especially the empty-loaded rate has become one of the important factors causing traffic congestion. Based on the empty-loaded rate survey of passenger cars on the two arterial roads in Shenyang, a model which inflecting the relationship among passenger cars’ empty-loaded rate and carpool rate and traffic volume is established and verified by comparative analysis and curve fitting, and the empty-loaded passenger cars driving condition is forecasted. The results show that the average passenger cars’ empty-loaded rate is about 67.4% and the passenger cars’ empty-loaded rate in the morning rush is between 56% and 84.3%. When the traffic congestion, the passenger cars’ empty-loaded rate is inversely related to traffic volume and the carpool rate is positively related to traffic volume in the morning rush, and the relationship between passenger cars’ empty-loaded rate and traffic volume is not significant in the flat peak. Study on passenger cars’ empty-loaded rate has great significance on improving traffic conditions, encouraging the carpool and reducing the traffic congestion.

The action of bus pulling in and out of bus stop on urban expressway has a spread effect on the main road traffic flow, which leads to the queue or traffic congestion on the main road during rush hours. By taking a section in the South Third Ring Road of Beijing as example, the traffic flow parameters of wave source in the upstream and downstream were investigated and analysed, and the parameters describing the fluctuation characteristics were obtained. The traffic fluctuation rules were also studied by spatial-temporal scales. By monitoring the abnormal changes in traffic fluctuations, a rapid responsive strategy can be given by the traffic management departments according to different types and levels of traffic disturbances, which can provide technology sustains and ensure the traffic safety.

Scientific optimization design of isolated intersection, which as the key point of city arterial road, is of great significance to improve traffic capability. The core intersection on the arterial road in Shenyang was selected as research object. Based on traffic parameter investigation and delay evaluation of intersection status, bus station settings, traffic organization and signal control were optimized and the optimization effect was simulated. The results show that intersection saturation and queue length decrease, while traffic flow average speed increase, further, vehicle average delay is reduced from 60 to 25 s, while intersection level of service is raised from E to C. The optimization effect is obvious and perfect. It suggests that the optimization design of intersection can actually not only reduce the traffic delay, improve the level of service, but also ensure city arterial road being safe and smooth.