| 摘要 |
In a vehicle navigation system, a memory stores branch road numbers as a part of links which indicate branch roads branching out from a main road or a rotary road. The branch road numbers are specific to the branch roads, respectively, and may be exit numbers of an expressway or the rotary road. The branch road numbers are identical with actual indication provided on roadside signboards which indicates respective branch roads. A navigation control unit provides a branching guidance in the course of a normal travel route guidance when a vehicle approaches a branching point. The control unit checks whether a branch road number is available, and retrieves it when available. This retrieved number is provided as a voice message to a driver.
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