Vehicle route planning system

Vehicle route planning system (10) uses a route planning apparatus (13, 19) to calculate a desired route between start and destination locations. Apparatus (16, 17) provides route information based on the calculated route. The route is calculated in accordance with fixed road path data stored in a memory (14). A user of the system (10) uses input devices (11, 12) to specify "detour" data that define what stored road path data should not be considered in calculating the desired route. A navigation computer (13) allows the system user to designate the detour data as "system detour data" to be used for excluding road path data for all routes calculated for all drivers to all destinations or to designate the user specified detour data as "subsystem detour data" which is used for excluding road path data for calculating some, but fewer than all, routes to be calculated. Preferably, the subsystem detour data includes driver ID associated detour (route calculation) data and/or trip associated detour data. The user designation and entry of different types of detour data allows the system ( 10) to achieve system flexibility while minimizing the time and effort involved by the user in entering detour data which may be used in calculating several trips.