1. Technical Field to Which the Invention Belongs
The present invention relates to a vehicle control system for controlling a vehicle on the basis of a road shape, as decided on the basis of map data comprised of a set of coordinate points obtained from a navigation system.
2. Discussion of Relevant Art
According to a previously proposed system (i.e., Japanese Patent Application Laid-Open No. 6-281471) of the same Assignee, a passable zone is set on a map on the basis of map data obtained from a navigation system, so that when a curve ahead of the subject vehicle of the driver goes out of the passable zone, a warning is issued to urge the driver to decelerate the vehicle, or an automatic braking or the like is actuated to effect an automatic deceleration.
In the aforementioned previously proposed system, however, it is decided whether or not the vehicle can pass through a curve far ahead of its actual position. As a result, arithmetic operations, not necessarily indispensable, are performed to increase loads on the arithmetic units. This raises a problem that the arithmetic units must have large capacities. When the road ahead is bent in S-shape, moreover, this S-shaped road may partially belong to an automatic deceleration zone or a warning zone, even if the curve is actually passable because a sufficient deceleration distance is present from the actual position to the curve. Then, the not-necessarily-indispensable automatic deceleration or warning may be executed to bother the driver.