Navigation system for motor vehicles

Abstract

A navigation system for a motor vehicle serves to guide the motor vehicle along an optimum route which includes bypass roads and side destinations desired by a driver but no road of high traffic congestion. When the motor vehicle deviates from the guidance route, an optimum route is again determined, starting from the current position of the motor vehicle. The navigation system includes a manipulating unit 1A for setting the desired bypass roads, side destinations and the final destination, a system controller 11 for setting the destination and the side destinations in terms of the coordinates on a map which are stored in a RAM unit together with information concerning the bypass roads and congested roads, a route extracting unit 6A for extracting an optimum route from a plurality of routes searched by a route search unit 5A on the basis of data read out from the RAM unit 14 and a route guidance controller for determining a distance deviation between the optimum route and the current position of the motor vehicle determined by a current position determining unit 7A. When the distance deviation exceeds a predetermined value, the system controller 11 commands the route search unit 5A and the optimum route extracting unit 6A to start again a new optimum route determining operation.