Research On Shortest Path And System Efficiency In Urban Transportation

Urban transportation system which mainly consisted of logistics and commuting is the vital important basis of the development of the city. However, several problems like traffic jam and exhaust pollution have arisen, which has become a heavy burden that prevent the city from further developing. Navigation service based on the huge traffic data has attracted wide attention from either the academic community or the industry. The application of huge traffic data provides the navigation service a more real and effective solution. In addition, the solution based on traffic flow theory improve the traffic efficiency of the urban transportation system in the global perspective. Therefore, it is meaningful to process the huge traffic data efficiently and program the traffic flow reasonably for the improvement of the quality and efficiency of the urban transportation system. The main research work of this paper consists of two part we talked above. The specific contents are stated as follows.First, topology is adopted to model and analyze the urban traffic network for the routing planning. In order to obtain the weight of the arc in the topology graph, the most important part of the routing planning, a hybrid speed model is proposed. The model distinguish the congested and uncongested mode of the traffic network with the help of the huge traffic data, and figure out the travel time of each road segment. The paper also analyzes the timevariant characteristic of the urban traffic network and shows the influence of the time-variant characteristic to the performance of the navigation service. Through simulations, navigation service can improve the efficiency of the single traveler when the huge traffic data and hybrid speed model is adopted.Further, considering the global performance of the whole urban traffic network, the paper carries the research of transportation efficiency in the global perspective. In order to study the traffic efficiency, a optimization problem is used based on the topology model. Taking both profit of single user and transportation of whole traffic network, the paper proposes the Efficiency Loss Alleviation(ELA) algorithm. The algorithm adopts the reword and punishment scheme, which not only alleviates the transportation efficiency loss by providing more path choices for drivers but also improves the fairness among drivers. The simulation results demonstrate the effectiveness of the proposed algorithm. At the same time, the communication technologies specified for VANET are proved that it can make up the efficiency loss brought by the low penetration rate of navigation services.