Abstract: The present invention provides a method and apparatus for generating a maneuver indication for an intersection having a turn-lane connector which is consistent with what a driver sees and expects. According to one aspect of the invention, it provides a method for providing maneuver indications to a driver for an intersection having a turn-lane connector which includes the steps of (a) determining when the intersection includes a turn-lane connector, (b) determining whether it is appropriate to collapse the turn lane into the main portion of the intersection for the purposes of generating a maneuver indication, (c) collapsing the turn lane into the intersection when it is appropriate, (d) generating a maneuver indication for the collapsed intersection, and (e) outputting the maneuver indication to the user in time so that the driver may use the turn-lane connector if desired.

Abstract: Methods for planning an optimum vehicle route from a selected origin to a selected destination with a selected departure time, taking account of the presence of timed turn restrictions and/or timed lane restrictions. Separate methods are provided for recalculation of a suitable route remainder, where an unanticipated timed turn or timed lane restriction or other traffic obstruction, such as a vehicle accident, is encountered enroute. Computations for an optimum route can be performed at the vehicle or at a station that communicates with the vehicle.

Abstract: A method for navigating with a vehicle navigation system using recognition of geographical region types in a map database. The system's map database stores information representative of a plurality of geographical region types. A geographical region type of a geographical region in which the navigation algorithm is operating is determined. At least one parameter related to the navigation algorithm is then set to correspond to the geographical region type. Navigation is performed using the navigation algorithm. Throughout the operation of the navigation algorithm, the system repeatedly determines whether the geographical region type has changed, and if so, changes the algorithm parameter(s) to correspond to the new geographical region type.

Abstract: A method for identifying highway access ramps in a database medium for use as locations for route calculation. Initially, first road segments which belong to a highway and which are connected to at least one access ramp are identified. The first road segments are sorted according to the highway to which they belong. A highway direction is determined for each first road segment. The first road segments belonging to a first highway are sorted according to highway direction. The first road segments belonging to the first highway and of each highway direction are sorted according to position, thereby forming a highway segment list for each direction of the first highway. Highway access ramps are identified for each first road segment in the highway segment list. The locations for the highway access ramps are stored in the database medium. Highway access ramps are identified in this manner for each highway in the database medium.

Abstract: Method and apparatus for providing precise universal time coordination or synchronization for each of a plurality of N vehicles, numbered consecutively i=1, 2, . . ., N (N.gtoreq.2) that move within a selected geographic region and that communicate by radiowaves with one or more base stations located within or adjacent to the selected region. Each vehicle is provided with a sequence of Satellite Positioning System (SPS) signals, with a sequence of SPS timing signals, and with a SPS signal transceiver/processor that receives the SPS signals and SPS timing signals and determines the present location of the vehicle and the time the vehicle location determination is made. One or more base stations broadcast a sequence of base station timing signals that are received by each vehicle.