Research On Spatiotemporal Strategies Of Releasing Dynamic Traffic Information

ABSTRACT: With more and more automotive vehicles are brought into use and expansion of population in cities, increasing traffic demands bring urban road networks great pressure. As land resources are decreasing and extension of urban road is more and more impossible, improving the efficiency of transport facilities utilization has become an important way to alleviate traffic congestions. By designing the reasonable message publishing range and cycle, the appropriate route guidance publishing strategy could optimize the guidance effect and finally realize the optimal assignment mode of network traffic flow. Specific to the two aspects, time and space, of the route guidance strategy the paper proposes two guidance models, respectively.For the spatiotemporal problems of releasing dynamic traffic information, this paper mainly studies from the following aspects.(1) Analyze the shortage of existing traffic information releasing range selection model, on the basis of studying the shortest path issue in directed network, the paper employs relevant covariance coefficient and the fuzzy set idea of Gaussian function and establishes a corresponding model. The simulation brings out a most-relevant matrix of the network which represents the maximum correlation degree in time and space between any two links in the network. Depending on the correlation degree, the message publishing range could be classified into different levels in order to prepare for deciding the direct publishing range. The model proposed is tested to be practical.(2) By comparing the respective impacts of iterative strategy and feedback strategy of average travel time with different guidance cycles, the effect of the length of guidance cycle on guidance results has been presented and analysis shows that the guidance strategy with long cycle is more stable. Considering both calculating simply and instability using feedback algorithms in the environment of long-cycle, the paper proposes a long cycle guidance strategy based on traffic condition under feedback strategy framework, and shows its validity by simulation.