Collision avoidance support apparatus

1. A collision avoidance support apparatus comprising:

a surroundings monitoring sensor including a camera sensor configured to take a picture of a view of an area ahead of a host vehicle so as to obtain image data representing said area, said surroundings monitoring sensor being configured to obtain information on an other vehicle which is a frontward vehicle present in said area based on at least said image data;

a turning angle actuator configured to vary a turning angle of said host vehicle; and

a control unit configured to:

obtain through calculation, using said image data, a target path for avoiding a collision between said host vehicle and said frontward vehicle, when said control unit determines, based on information obtained from said surroundings monitoring sensor, that a collision probability condition becomes satisfied, said collision probability condition being a condition to be satisfied when there is a probability that said host vehicle collides with said frontward vehicle; and

start performing a collision avoidance steering control to control said turning angle actuator to cause said host vehicle to travel along said target path, when it is determined that a predetermined collision avoidance steering control start condition becomes satisfied,

wherein,

said control unit is configured to:

obtain planned collision avoidance direction information indicative of a planned collision avoidance direction indicated by said target path, said planned collision avoidance direction being either a leftward direction or a rightward direction and being a direction which said target path causes said host vehicle to change a moving direction to;

determine, based on said image data, whether or not a state of turn indicators of said frontward vehicle is a turning direction indicating state that is a state in which said turn indicators are indicating an expected moving direction of said frontward vehicle;

obtain, based on said image data, information on an indicated direction that represents which one of said leftward direction and said rightward direction said expected moving direction is, when it is determined that said state of turn indicators is said turning direction indicating state;

set said collision avoidance steering control start condition to a first start condition that is a condition to be satisfied when an inter-vehicular distance between said host vehicle and said frontward vehicle becomes equal to a first distance, when it is determined that said state of turn indicators is not said turning direction indicating state;

determine, based on said information on said indicated direction and said planned collision avoidance direction information, whether or not said expected moving direction of said frontward vehicle is a direction that is the same as the planned collision avoidance direction;

prohibit executing said collision avoidance steering control when it is determined that said expected moving direction of said frontward vehicle is said direction that is the same as said planned collision avoidance direction; and

set said collision avoidance steering control start condition to a second start condition that is a condition to be satisfied when said inter-vehicular distance becomes a distance that is shorter than said first distance of when said first start condition can be satisfied, when it is determined that said expected moving direction of said frontward vehicle is a direction that is different from said planned collision avoidance direction.

2. The collision avoidance support apparatus according to claim 1 , wherein,

said collision avoidance steering control start condition includes at least a condition to be satisfied when a collision probability indicating value indicative of a probability that said host vehicle collides with said frontward vehicle reaches a collision probability threshold; and

said control unit is configured to set said collision probability threshold used in said second start condition to a value different from said collision probability threshold used in said first start condition.

3. The collision avoidance support apparatus according to claim 1 , wherein,

said collision avoidance steering control start condition includes at least a condition to be satisfied when a collision prediction time that is a predicted time length until said host vehicle collides with said frontward vehicle is shorter than a predetermined collision determination threshold time; and

said control unit is configured to:

set said collision determination threshold time used in said first start condition to a first time; and

set said collision determination threshold time used in said second condition to a second time shorter than said first time.