Vehicle cruise control system

A cruise control system is configured to cancel or prohibit cruise control depending on the operating state of the wipers of a vehicle to improve the convenience of the cruise control by securing a wide enough range of operating conditions in which cruise control can be executed. When the wipers are operating in a continuous operation mode and low speed following cruise control is in progress, execution of the low speed following cruise control is continued (steps S6, S14). When the wipers are operating in a continuous operation mode and high speed following cruise control is in progress, execution of the high speed following cruise control is continued if the vehicle speed is in the vehicle speed overlap region (step S8) or if a preceding vehicle is detected (steps S10 and S14) (i.e., even if the vehicle speed is not in the vehicle speed overlap region). When the wipers are operating in a continuous operation mode and high speed following cruise control is in progress, the high speed following cruise control is canceled if the vehicle speed exceeds the vehicle speed overlap region and a preceding vehicle is not detected (steps S6 to S12).