An autonomous control system for a vehicle that controls the speed and steering system of the vehicle to operate in a lane-keeping mode or a lane-changing mode. Position sensors sense the location of surrounding vehicles. A lane determining system identifies a current lane where the vehicle is located. A source of oncoming lane course data provides information as to the course of the current lane. A controller provides instructions to the steering system and speed control system to maneuver the vehicle in either the lane-keeping mode or the lane-changing mode. The driver may override the control system by providing a manual input to the steering system or the speed control system.