Studies On Properties And Control Strategies Of Incident-based Non-recurrent Traffic Congestion Propagation

Currently, traffic congestion has become one of main bottleneck which restricts the development of urban city and has influence on the quality of daily life. To date, traffic management agency lack of scientific understanding of the mechanism of traffic congestion propagation and the spatial-temporal distribution of incident based non-recurrent congestion. While making certain congestion control strategies, people who dependent on the experience need for more theoretical support. Thus, in-depth study of spatial-temporal distribution of incident-based traffic flow and systematic analysis on the impact of control strategies on non-recurrent congestion propagation are needed. It is also important to locate optimal information broadcast, make reasonable route guidance and control strategies to alleviate urban traffic congestion.In order to analysis the effect of information broadcasting, route guidance and control strategies on spatial-temporal distribution of incident based non-recurrent congestion, the cellular transmission model based congestion propagation simulation is found. Based on this model and combining with the dynamic route choice model of trip makers, the mentioned above issue were studied and evaluated. The main contents of the dissertation are summarized as follows:(1) To introduce the method of studying on traffic congestion propagation mechanism and analysis of the propagation evolution principle of traffic flow. On this basis, the calculated method of actual link travel time, real-time link travel time and corresponding route travel time are proposed. Based on the output of CTM simulation, the traffic congestion evaluation system is found which comprise traffic congestion delay, traffic congestion scope, traffic congestion duration, average instantaneous link travel time, average link travel time and system total cost to evaluate the spatial-temporal distribution of incidnet-based congestion.(2) Based on the CTM simulation, the impact of factors such as traffic condition, reduction of link capacity, incident location and duration on the congestion propagation. The simulation results show that the factors mentioned above will affect the propagate speed, scope, intensity, duration greatly. The kinematic wave theory is able to explain simulation results well. (3) Information of real-time traffic condition is able to alleviate incident-based congestion. The dynamic route choice behavior of trip makers with information providing is modeled based on the dynamic stochastic user equilibrium principle in this paper. On this basis, the affect of the quality of information, the proportion of trip makers equipped with information device and the compliance rate of real-time traffic information are analysised. The simulation results show that the factors mentioned above have great effect on the alleviation of congestion.(4) Based on the spatial-temporal distribution of incident-based non-recurrent congestion, the cutset-based congestion control strategies are provided. The reasonable temporary vehicles bans are able to prevent the propagation of congestion to upstream and promote dissipation of the queue. Based on the assumption of route choice behavior of trip makers under temporary vehicles bans, the optimal design method of temporary vehicles bans is studied. The practicability of cutset-based temporary vehicles bans is better than others such as line-based temporary vehicles bans, area-based temporary vehicles bans and diamond shape-based temporary vehicles bans. The simulation results show that the proposed cutset-based temporary vehicles bans are able to alleviate traffic congestion and improve the system performance of urban city network.(5) Based on the CTM simulation and methods of calculating real-time travel time, the divert mechanism and location of variable message board is studied. The GA-based algorithm is proposed to solve this issue. The simulation results show that the variable message board with optimal located are able to alleviate non-recurrent traffic congestion on black-spot links and have good robustness. Combining the variable message board with temporary vehicles bans, the spatial-temporal complementary of them will make these strategies more suitable for preventing the congestion propagation, reducing delay and improving system performance.