Collision avoidance assist apparatus

A collision avoidance assist apparatus, comprising:

• a lane marking recognition device which recognizes a left lane marking and a right lane marking provided on a road on which a vehicle moves;
• an obstacle recognition device which recognizes an obstacle in an area ahead of the vehicle;
• an electric motor which applies a steering torque to a steering mechanism including a steering wheel of the vehicle to change a steering angle of at least one steered wheel of the vehicle;
• and
• an electronic control unit configured to:
• calculate a lane marking recognition reliability level representing a reliability level of an overall recognition result on the left and right lane markings;
• and
• execute an emergency steering control including processes to:
• determine a target steering torque which changes the steering angle to avoid a collision of the vehicle with the obstacle without moving the vehicle out of the moving lane when (i) the electronic control unit determines that the vehicle has a high probability of colliding with the obstacle, (ii) a moving lane defined by the left and right lane markings is a straight lane, and (iii) the calculated lane marking recognition reliability level is equal to or higher than a first threshold reliability level;
• and
• drive the electric motor to apply the steering torque corresponding to the determined target steering torque to the steering mechanism,
• wherein the electronic control unit is configured to stop executing the emergency steering control when the lane marking recognition reliability level becomes lower than a second threshold reliability level set to a value lower than the first threshold reliability level.