中文摘要：

智能交通中的路径诱导系统能够极大地提高人们的出行效率与出行体验。经典A＊算法只注重搜索精度而忽略了搜索效率，在城市道路网络分层的基础上，对高层道路使用的A＊算法进行了改进，对于道路网络中的不同节点，设置估价函数具有不同的权值，同时给定权值的一个上下限阈值，以平衡算法的搜索效率与搜索精度。实验表明，得到的最短路径虽然不是常规的距离最短却是实际行驶时间最优的。

英文摘要：

Intelligent transportation route guidance system can greatly improve the efficiency and experience of travel. Classic A＊ algorithm to focus only on the search precision while ignoring the search efficiency, this paper introduces a improved high-level A＊ algorithm based on Hierarchy of the urban road network, evaluation function with different weightings for different nodes in the road network, meanwhile it sets an upper and lower limiting threshold value of the weight to balance the efficiency and accuracy of search. The experiments show that this shortest path is though not the shortest conventional length but the real travel time optimal.