Route guiding method for in-vehicle navigation device

摘要

A route guiding method for an in-vehicle navigation device. To guide a vehicle to a destination by an optimum route, it is determined whether the vehicle is on track within a predetermined intersection range based on route guidance data received from a traffic information center via a mobile communication network. If the vehicle is on track within the intersection range, it is determined whether the vehicle is in a free run state according to predetermined free run conditions to prevent a preliminary route guidance message that is confusing to a driver in the free run state. According to the determination result, the preliminary route guidance message is selectively provided.