Average vehicle speed calculation device

摘要

In a navigation system for vehicles, a type of road a vehicle travels is determined based on a present position of a vehicle and road data, and a change in the type of road is determined. The road type is determined based on the type of link the vehicle travels referring to a table storing a relation between a link type and a road type. A travel distance is accumulated until the travel distance exceeds a predetermined determination reference, when the road type remains unchanged. An instant vehicle speed is calculated each time the vehicle travels the determination reference. An average vehicle speed is calculated by using the instant vehicle speed calculated for each road type. The average vehicle speed is used to notify an estimated time of arrival at a destination or a passing point.