Method and apparatus of vehicle navigation system for detecting and avoiding city with crowded streets

摘要

A system for comparing various routes, identifying delays among the routes, and selecting a more desirable route, even if the desirable route is not the shortest distance, is described. In one embodiment, the more desirable route is the faster route. In one embodiment, the more desirable route is a route with fewer in-route delays. In one embodiment, the system loads a map from a memory and retrieves road level information based on position information of roads and delays. The roads in the map are described at various levels of detail, wherein lower levels contain more detail and relatively higher levels that contain less detail. One embodiment includes detecting a route having links with a substantially larger number of delays and adding an additional penalty cost for the links at higher levels based on penalties computed from the links at lower level road levels. If a current road level is not the highest, one embodiment include adding the additional penalty cost into a “penalty list” of a higher level link having the links of a current road level in order to detect the higher links with a large number of delays while calculating route at a higher level. When calculating a route (or portion of a route) at a higher road level, an additional penalty cost is added to the higher level links if based on the penalty list.