Vehicle drive assist system

A drive assist system for an own vehicle at least having solid object detecting unit for detecting frontal solid objects including a preceding vehicle traveling ahead of said own vehicle and a second preceding vehicle traveling ahead of said preceding vehicle and traveling control unit including constant speed traveling control unit for controlling a vehicle speed of said own vehicle so as to travel at a constant speed and follow-up traveling control unit for establishing said preceding vehicle as a follow-up object and for controlling a traveling of said own vehicle so as to follow up said preceding vehicle, comprising:

• means for inhibiting an acceleration of said own vehicle following up said preceding vehicle according to said follow-up traveling control unit when a first state where said preceding vehicle undertakes to pass said second preceding vehicle is detected;
• means for continuing to establish said preceding vehicle as said follow-up object until a second state where said preceding vehicle travels in parallel with said second preceding vehicle is detected;
• means for changing said follow-up object from said preceding vehicle to said second preceding vehicle when said second state changes to a third state where the speed of said preceding vehicle is larger than that of said second preceding vehicle;
• and
• means for continuing to establish said preceding vehicle as said follow-up object when said second state changes to a fourth state where the speed of said preceding vehicle is smaller than that of said second preceding vehicle.