Study On Theory And Method Of Travel Time Reliability About Road Network

The national medium-and-long-term planning for development of science and technology (2006-2020) issues supporting polices as strategic task of transportation science and technology. Those are to develop a modern comprehensive transportation system and to solve three crux transportation problems, which are energy dissipation and pollution, traffic safety and traffic jam in metropolis. The efforts trying to ease traffic congestion are highlighted through enhancing trip efficiency of travellers, reliability and maximum utilization road resources in the light of the fact that feasibility of data collection and travellers' expectation of high travel quality. In this dissertation main theories and methods of travel time reliability were discussed to evaluation the performance of road network. Based on reliability theory, the road network reliability model was proposed and the theory support about performance and service of road network can be obtained by using the method of combining theory with reality, processing with qualitative and quantitative analysis.The dissertation was made up of the following parts:Firstly, based on the previous related literature studies on reliability index and model, the guidance about reliability analysis dealing with large quantities data was proposed. Secondly, in view of travel time reliability lack of effective description, an integrated index system was put forward, including target hierarchy, rule hierarchy and index hierarchy, which were used to satisfy various requirements. The index system took a certain section from Dongzhi Men to Chaoyang Men as example, and some conclusions about trip tactics can be obtained. Thirdly, compared with the previous models and evidence study, stochastic network reliability model where link travel time obeyed beta distribution was proposed. In practicality, the model parameters were improved and the model can be solved by combined Frank-Wolfe method and Method of Successive Average. Fourthly, the effects of multi-factor including link travel time, perceptive error, traffic demand and capacity on travel time reliability can be estimated by performing various reliability trails and measures to improve reliability can be obtained. Fifthly, there were two types of link on the road network according to whether it contained the vehicle detectors or not. The stochastic network model was improved and corresponding algorithm can be obtained. Sixthly, the relation between travel time reliability and capacity reliability was researched from various network hierarchies, involving path, OD pair or the whole network. Finally, hybrid model based on Wardrop principle and corresponding algorithm was enacted. The following innovative conclusions were drawn through the studies on the travel time reliability index system, its reliability model and the application of reliability:1, The principle of indices was put forward and the index system was set up based on the research into road network. The indices included three-layer infrastructure for travel time reliability assessment, which were target hierarchy, rule hierarchy and index hierarchy respectively. The index system helped reflecting properties of road network where users can find their suitable service from various spatio-temporal frameworks.2, Previous attempts to estimate travel time reliability were contribute little to deal with numerous detected data. Therefore, the guideline for travel time reliability evaluation was introduced. This was not only redounding to take full advantage of current road resources but also to offer reliability of existing road network as checkout criterion for reliability design.3, After being compared with previous efforts to model reliability, stochastic reliability model was reconstructed where link travel time obeyed beta distribution from empirical study. The model parameters can be simplified in practically and corresponding algorithm combined Frank-Wolfe method with Method of Successive Average was presented. The efficiency of algorithm can be improved when the inner cycle was reduced. To assess the performance of road network, lots of reliability trails were performed.4, Hybrid model was proposed which was made up of two parts: when travellers supplied with information, route choice criterion in one model was to minimize the disutility associated with a route; otherwise, to maximize the travel time reliability of a route. The dependence between links was considered to model travel time reliability.