Study On The Selection Strategy Of The Road Section For The Repair In Transportation Network

Transportation network takes an important task of transporting mass passengers and freights. However, some road sections may be fail at certain times (e.g. blocked by unexpected events such as pipeline laying, road reconstruction or maintenance), which influences the normal travel of travelers. At present, the problem of a road section removal results in the increase of the length of a path between two nodes in a graph has been studied. Previous studies applied the shortest-path-counting problem and the variety of the maximum flow in a transportation network to evaluate the importance of a road section of a shortest path of a transportation network. In practice, there is lack of the choice of the road section for the repair, and the road section for the repair is often in a disorder condition. Considering this situation, from the perspective of the loss of real-time detour and the enhancement ratio of the sum travel times, this paper proposes indexes of inflection of the repairing road section whose removal produces blockages on the transportation network, and gives some selection strategies of repairing road sections. One aim is to make up for the previous research shortage; the other aim is to combine the theoretical results with road repairs in actual road construction, and give some suggestions for policy-makers to plan road sections.The main work and creative achievements of this paper are as follows:The model of the option for repairing road section of real-time detour loss is established, a genetic algorithm is used for solving the model. The loss coefficient of real-time detour which can measure the impact of repairing road section on transportation network is proposed from the point of real-time detour loss after the traveler encounter the repairing road section, whose removal produces the ratio of the actual length of path to the original length of path. The paper gives the definition of the repairing road section of maximum real-time detour loss on any path, the vital repairing road section between any point pair, and the vital repairing road section of the network, then the property is analyzed and the model is established. And the paper designs the algorithm and analyzes the time complexity of the algorithm. Finally. Xincheng area local network in Xian city as an example, it demonstrates that the algorithm can solve the problem efficiently.The model of the option for repairing road section of enhancement ratio is established, a genetic algorithm is used for solving the model. The enhancement ratio coefficient of the minimum sum travel times which can measure the impact of repairing road section on transportation network is proposed from the point of the increase of the minimum sum travel times after the traveler encounter the repairing road section, whose removal produces the ratio of the minimum sum travel times after the road section is repaired to the before. To minimize the enhancement ratio coefficient of the minimum sum travel times, the paper gives the model and algorithm of the repairing road section of minimum enhancement ratio coefficient of the network under the assumption that the traveller known in advance all repairing road sections and unknown. Finally, Lianhu area local network in Xian city as an example, it gives the results of the repairing information known and unknown, and demonstrates that the algorithm can solve the problem efficiently.