Improving hierarchical route computations for roadway networks

In most hierarchical routing algorithms, the origin and destination at the lower map level are not represented at the higher level. This often leads to a less optimum solution than desired. In this paper, we propose a novel routing strategy, which relies on promoting the origin and destination nodes to the higher level in order to improve the accuracy of the route computation. The proposed technique adopts smaller natural grids, which allows for the incorporation of origin-and-destination pair and concatenation of any two natural grids. It is shown that the technique developed lends well for managing large cities and that the increase in the average travel time is minimal. Moreover, the proposed routing strategy leads to the reduction in the maximum number of nodes that are involved in the computation at all levels of the hierarchy