Optimal Route Choice In Urban Road Network

Nowadays, the traffic jam problem is more and more outstanding, so how to achieve the optimal route selection in driving process is especially important. There is an effective method for this problem, which is to perfect the routing algorithm in real-time and effectiveness and build up high efficient intelligent transportation system. According to these measures, the optimal route selection must be built as the focus of the study.In intelligent transportation system, optimal route selection is a very important issue. It can get the real-time optimal route according to traffic net-work information stored in the system. The purpose of realizing the optimal route selection is to help the driver to choose a route between the departure and destination according to their own priority principles (the shortest, or the lowest cost, or the best road condition, etc.)As the traditional route choice algorithm, Dijktra algorithm belongs to the typical local optimum algorithm and its aim is to get the optimal route in a stationary state. However, the actual situation of the road transport network is changing, and this requires that new approaches to get the optimal route in a dynamic state are used. To realize this target, two major efforts must be done. The one is how to get real-time road impedance; the other is how to get the optimal route based on the real-time road impedance.This paper mainly studied the above two aspects. To get real-time road impedance, a new idea which is to fit the actual traffic data based on GM (1,1) model and get the real-time impedance function is proposed. Gray theory has no stringent requirements on sample size, and the sample is not required to follow any distribution. It uses data generation approach to search for hidden data in the chaotic law, and also uses uncertain system (such as the known small sample, poor information, etc.) as a study to predict unknown information system, which changes the system from 'grey' to 'white'. According to the features of gray theory, the impedance function consistent with the road situation is established based on GM (1,1) model. For solving the dynamic optimal route, several algorithms (tabu search algorithm, simulated annealing algorithm, genetic algorithm and ant colony algorithm) are introduced in this paper. Among them the ant colony algorithm is chosen as the research method in this paper. This algorithm has the advantage that when there is a large amounts of data in the traffic or when the road traffic is complex, it can be to play bionic algorithm greatly advantage of global search and improve the efficient of choice to realize the optimal route selection.Finally, the author combined the impedance function which is built up based on GM (1,1) model with the ant colony optimization, and got the flow chart. The specific implementation methods require further study.