Research Of Approximate Algorithm On Travel Time Reliability Of The Stochastic Traffic-flow Network

Along with the city's fast-development, the transportation network reliability has received the high attention. At present, there are mainly two kinds of computational methods in the road network reliability research: one is the precise algorithm, the other is the approximate algorithm. As the transportation network is the open great system and the transportation supply-demand has the characteristic of random change, so it is impractical in precise calculating the transportation network reliability and needs to approximately calculate the reliability of the transportation network. In the approximate algorithms of enumerating the network states, there are mainly two kinds: one is to enumerate the most possible states of the network which has more researches, among them, the algorithm is quite effective in calculating the probability index. However, the computation precision is comparative lower in calculating the importance index. Compared with it, another enumerating the most important states of the network has a few researches, among them, the algorithm is quite effective in calculating the importance index. However, the computation precision is comparative lower in calculating the probability index.In this thesis, on the basis of MI algorithm (which can enumerate the most important states of the network) and MP algorithm (which can enumerate the most possible states of the network), the author builds the MIMP algorithm (which can simultaneously enumerate the most important states and the most possible states of the network). The algorithm can divide the produced network states into four types: The first is the bigger possibility states which has bigger influence on the reliability of the network important index; The second is the bigger possibility states which has smaller influence on the reliability of the network important index; The third is the bigger possibility states which has no influence on the reliability of the network important index; The fourth is the smaller possibility states which has bigger influence on the reliability of the network importance index. So relying on these four types of network states, the MIMP algorithm can approximately calculate the road network reliability index.Finally, three algorithms will be applied respectively in calculating the specific example. Through comparative analysis, it obtains the satisfying result.