Study On Simplified Road Network Models And Path Planning For The Urban Traffic

Nowadays,with traffic congestion in cities are more and more serious ,travelers'requirements for simple and efficient path planning are more urgent. It has a very important significance of constructing a reasonable and effective road network model according to the reality of the road traffic conditions , and executing efficient path planning based on the road network model according to traveler'need. In practice, more complex traffic restriction information (for example, road width, traffic volume, a certain road is no thoroughfare for construction, road traffic accidents and other provisions ) are taken into account in common road network model and the goal of path planning will meet the travelers'requirements to execute single-target or multi-objective planning.Currently, in international, there is more research on road network model, for example , the complex static road network model and the dynamic road network model and real-time network model. Although these complex network models could better describe the real traffic situation to some extent, but they are generally more numerous considerations, such as the length of the ring road, the traffic flow of the intersection should be considered to calculate the intersection delay, otherwise the dynamic traffic flow should be considerable. All of these will complex the design of algorithms, and decrease the computational efficiency, it will be hard to capture the real road information, and it will not meet the navigation requirements finally. In response, the paper focuses on how to ensure the path planning results in the premise, as far as possible to consider less factors to simplify the road network model, in order to better respond to the navigation requirements of urban travelers. Thesis main contributions are as follows:①First, the paper proposes a simple and practical simplified static network model based on the basic characteristics of urban traffic,. And designed a improved Dijkstra algorithm, S-Dijkstra algorithm on the basis of the model, to solve the problem of path planning for the city. The model requires only a few road traffic information collected, but it can reflected path delay, traffic speed, traffic lights and zebra crossings and other complex factors on the indirect effects of the travel time of vehicles, with a simple and practical features.②Then, by following the dynamic changes of urban transport special laws, within one business day period is divided into different time periods, to extend the above simplified model was constructed by a simplified time-based dynamic network model. A given m improved Dijkstra algorithm, D-Dijkstra algorithm, to solve for the dynamic city car navigation path planning problem based on the model.③Finally, designed a improved highly efficient Dijkstra algorithm toward narrowing the search space in order to achieve the optimization of path planning. The new method could improve the efficiency of the navigation algorithm.The simplified road network models proposed by this paper have lots of characters, for example, simplify the data capture, easy execute and the algoritm is simple and effective. All of this could meet the requirements of the reality and get more wealth of the considerable research.