Abstract

A vehicle control system reduces the arithmetic operations for deciding the passableness of the vehicle through an upcoming curve and also avoids unnecessarily effecting automatic deceleration and warning, which are not completely indispensable in a system for performing the warning or automatic deceleration, so that the vehicle may pass through a curve at a proper vehicle speed and with minimum distraction to the vehicle occupants. Assuming that the driver performs a voluntary deceleration at a predetermined deceleration from the current vehicle speed, the system calculates an estimated passage speed of a tentative position Nk, as set on a road ahead of an actual position P0. The system then sets a passable zone Z1, a warning zone Z2 and an automatic deceleration zone Z3 on the basis of turnable radii R1 and R2, at which a predetermined transverse acceleration is established at the estimated passage speed, as well as an arc C1 ' defining a range of a predetermined distance from the tentative position Nk. The driver is warned by the system, when any of nodes Nk+1, - - - , and soon ahead of the tentative position Nk is present in the warning zone Z2, and the vehicle is automatically decelerated by the system when any of the nodes is present in the automatic deceleration zone Z3.