Abstract: A navigation system (100) guiding a driver of a vehicle has a receiver (102) for the reception of traffic message. The navigation system has a filter module (104) that determines the delay caused by the event of the received traffic message. The filter module only transfers the traffic message to the process module (106) of the navigation system if the delay is larger than a threshold (108).

Abstract: An apparatus for supplying traffic-related information in a vehicle receives a message concerning a traffic-related event, for instance a traffic queue. This message contains information about the location of the traffic-related event. The apparatus calculates the time and/or distance interval between the location of the event and the current position of the vehicle and gives an alarm if the time and/or distance interval is smaller than a predetermined time and/or distance interval.

Abstract: In a navigation system a driver of a vehicle is guided along a planned route (310) from an origin to a destination. The system comprises a receiver (122) for receiving a traffic message of an actual travel condition concerning a road-element. The system comprises an evaluation module (126) to determine whether the received traffic message makes it necessary to plan a new route to the destination. If a traffic message is received for a road-element which does not form a part of the planned route (212), the evaluation module determines whether the message indicates an improvement (204) of the travel condition of that road-element and if this is so then the planning module plans a new route.

Abstract: A method for accessing a data item from a data base has the full data base contained in a plurality of blocks in a slow background memory and furthermore has a faster foreground memory. Each data item has a label containing one or more elements. The data base furthermore has an index containing a second multiplicity of treewise organized index items each comprising an initial part of its label header, one or more secondary pointers and an indication of whether all data items having that initial part are contained in only one or in a plurality of blocks. First the index is accessed with the initial part of the label. If the index item pertaining to the latter initial part signals is contained in only a single block, the pointer in that index item points to that single block and the block is stored in the foreground memory. Extending the initial part to a full header identifies an intended subset of data items for accessing through its completed label.

Abstract: A database is stored in a mass memory. For this purpose, it is first divided into main cells and then into base cells according to a predetermined regular division pattern. Each base cell is then checked to see whether its data content is sufficient to occupy substantially completely a storage parcel having a predetermined capacity. If this is the case, the base cell is thus accommodated in a storage parcel; if this is not the case, adjacent base cells are grouped until a storage parcel is occupied substantially completely. The operation of addressing a storage parcel is effected by the use of a main cell table in which address pointers are stored, each of which points to a base cell table. In the base cell table, an index is given for each base cell and this index indicates in which storage parcel the relevant base cell is accommodated.