Patent Publication Number: US-2022234654-A1

Title: Vehicle collision avoidance assist apparatus

Description:
BACKGROUND 
     Field 
     The invention relates to a vehicle collision avoidance assist apparatus. 
     Description of the Related Art 
     There is known a vehicle collision avoidance assist apparatus which executes a forcibly braking control of forcibly braking and stopping an own vehicle to avoid collision of the own vehicle with an object ahead of the own vehicle when the own vehicle probably collides with the object. Also, there is known a vehicle collision avoidance assist apparatus which executes a steering avoidance control of forcibly steering the own vehicle to avoid the object to avoid the collision of the own vehicle with the object when the vehicle collision avoidance assist apparatus predicts that the own vehicle cannot avoid the collision with the object even by forcibly braking the own vehicle (for example, see JP 2017-43262 A). 
     In order to avoid the collision of the own vehicle with the object by the steering avoidance control, the own vehicle is forcibly steered right and left. When the own vehicle is forcibly steered right and left, and the own vehicle is considerably deviated or departed from the avoidance route, preferably, an execution of the steering avoidance control should be stopped. In order to stop executing the steering avoidance control appropriately, a condition that a departing amount of the own vehicle from the avoidance route can be employed as a condition of stopping executing the steering avoidance control. However, if this condition is employed, the execution of the steering avoidance control may be stopped at an excessively late or early timing. 
     SUMMARY 
     An object of the invention is to provide a vehicle collision avoidance assist apparatus which can appropriately stop the execution of the steering avoidance control. 
     According to the invention, a vehicle collision avoidance assist apparatus comprises an electronic control unit configured to execute a steering avoidance control. The steering avoidance control is a control of setting an avoidance route for avoiding the collision of the own vehicle with the object in a lane in which the own vehicle moves and executing an avoiding steering process of forcibly steering the own vehicle so as to move the own vehicle along the avoidance route when an index value representing a probability of collision of an own vehicle with an object ahead of the own vehicle becomes equal to or greater than a predetermined index value. The electronic control unit is configured to stop an execution of the steering avoidance control when a departing amount of the own vehicle from the avoidance route becomes equal to or greater than a predetermined departing amount while the electronic control unit executes the steering avoidance control. The predetermined departing amount is set for each of sections of the avoidance route. 
     If the execution of the avoiding steering process is continued after the own vehicle is considerably departed from the avoidance route, the own vehicle may collide with the object. With the invention, the execution of the steering avoidance control is stopped when the departing amount of the own vehicle from the avoidance route becomes equal to or greater than the predetermined departing amount. Thus, the collision of the own vehicle with the object can be prevented when the own vehicle may collide with the object due to the execution of the avoiding steering process of the steering avoidance control being continued. 
     Further, while the own vehicle is moved along the avoidance route by the avoiding steering process, the steering angle of the own vehicle is increased, decreased, and kept. When the own vehicle is moved properly by the avoiding steering process, the departing amount of the own vehicle from the avoidance route with the steering angle of the own vehicle being increased and decreased, tends to be greater than the departing amount of the own vehicle from the avoidance route with the steering angle of the own vehicle being kept. That is, even when the own vehicle is properly moved by the avoiding steering process, the departing amount of the own vehicle from the avoidance route varies, depending on which section of the avoidance route the own vehicle moves. Thus, if the predetermined departing amount is set to a fixed value, independently of whether the steering angle of the own vehicle is increased, decreased, or maintained by the avoiding steering process, the execution of the steering avoidance control is not stopped even when the execution of the steering avoidance control should be stopped. Alternatively, even when the execution of the steering avoidance control should not be stopped, the execution of the steering avoidance control is stopped. With the invention, the predetermined departing amount is set for each of the sections of the avoidance route. Thus, the execution of the steering avoidance control can be appropriately stopped. 
     According to an aspect of the invention, the sections of the avoidance route may include (i) at least one steering section of the avoidance route that the steering angle of the own vehicle is increased or decreased by the avoiding steering process and (ii) at least one steering keeping section of the avoidance route that the steering angle of the own vehicle is kept. In this aspect, a first departing amount may be set as the predetermined departing amount when the own vehicle is moved in the steering section of the avoidance route by the avoiding steering process. Further, in this aspect, a second departing amount smaller than the first departing amount may be set as the predetermined departing amount when the own vehicle is moved in the steering keeping section of the avoidance route by the avoiding steering process. 
     In general, even when the own vehicle is properly moved by the avoiding steering process, the departing amount of the own vehicle from the avoidance route when the own vehicle is moved in the steering section of the avoidance route, tends to be greater than the departing amount of the own vehicle from the avoidance route when the own vehicle is moved in the maintaining section of the avoidance route. With this aspect of the invention, the first departing amount set as the predetermined departing amount when the own vehicle is moved in the steering section of the avoidance route, is greater than the second departing amount set as the predetermined departing amount when the own vehicle is moved in the maintaining section of the avoidance route. Thus, the execution of the steering avoidance control is appropriately stopped. 
     According to another aspect of the invention, the predetermined departing amount set when the own vehicle is departed from the avoidance route in an opposite direction to a turning direction of the own vehicle achieved by the avoiding steering process, may be smaller than the predetermined departing amount set when the own vehicle is departed from the avoidance route in the same direction as the turning direction of the own vehicle achieved by the avoiding steering process. 
     Even when the own vehicle is departed from the avoidance route in the same direction as the turning direction of the own vehicle achieved by the avoiding steering process, and the departing amount is a certain amount, the own vehicle may not have an unstable moving behavior due to a slip of wheels of the vehicle. However, when the own vehicle is departed from the avoidance route in the opposite direction to the turning direction of the own vehicle achieved by the avoiding steering process, and the departing amount is the same certain amount, the own vehicle may have an unstable moving behavior due to a slip of the wheels of the vehicle, and thus the own vehicle may collide with the object. In this case, the execution of the steering avoidance control should be stopped. With this aspect of the invention, the predetermined departing amount to be compared with the departing amount when the own vehicle is departed from the avoidance route in the opposite direction to the turning direction of the own vehicle achieved by the avoiding steering process, is smaller than the predetermined departing amount to be compared with the departing amount when the own vehicle is departed from the avoidance route in the same direction as the turning direction of the own vehicle achieved by the avoiding steering process. Thus, the collision of the own vehicle with the object can be prevented when the own vehicle is departed from the avoidance route in the opposite direction to the turning direction of the own vehicle achieved by the avoiding steering process. 
     According to further another aspect of the invention, the index value may be a predicted reaching time which is a time predictively taken for the own vehicle to reach the object. In this aspect, the index value may increase as the predicted reaching time decreases. Further, in this aspect, the predicted reaching time may be acquired, based on (i) a distance between the own vehicle and the object and (ii) a relative moving speed of the own vehicle with respect to the object. Furthermore, in this aspect, the steering avoidance control may be executed when the predicted reaching time becomes a predetermined predicted reaching time which corresponds to the predetermined index value. 
     In order to execute the steering avoidance control with preventing an unnecessary execution of the steering avoidance control, it is effective to determine a timing of starting the execution of the steering avoidance control, based on the time taken for the own vehicle to reach the object. With this aspect of the invention, whether the execution of the steering avoidance control should be started, is determined, based on the time predictively taken for the own vehicle to reach the object (i.e., the predicted reaching time) as the index value. Thus, the steering avoidance control can be executed with preventing the unnecessary execution of the steering avoidance control. 
     Elements of the invention are not limited to elements of embodiments and modified examples of the invention described with reference to the drawings. The other objects, features and accompanied advantages of the invention can be easily understood from the embodiments and the modified examples of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view which shows a vehicle collision avoidance assist apparatus according to an embodiment of the invention and an own vehicle on which the vehicle collision avoidance assist apparatus according to the embodiment of the invention is installed. 
         FIG. 2A  is a view which shows lane markings which define a lane in which the own vehicle moves. 
         FIG. 2B  is a view which shows a yaw angle of the own vehicle. 
         FIG. 2C  is a view which shows the yaw angle of the own vehicle. 
         FIG. 3A  is a view which shows an own vehicle moving area. 
         FIG. 3B  is a view which shows a scene that a vehicle as an object is in the own vehicle moving area. 
         FIG. 3C  is a view which shows a recommended avoidance route along which the own vehicle is moved to avoid the vehicle as the object. 
         FIG. 3D  is a view which shows a target avoidance route along which the own vehicle is moved to avoid the vehicle as the object. 
         FIG. 4A  is a view which shows a scene that an execution of a steering process or an avoiding steering process of steering the own vehicle to move the own vehicle along the avoidance route, is started. 
         FIG. 4B  is a view which shows a scene that the avoiding steering process is being executed. 
         FIG. 4C  is a view which shows a scene that an execution of a steering avoidance control is terminated. 
         FIG. 5A  is a view which shows a scene that the execution of the steering process or the avoiding steering process of steering the own vehicle to move the own vehicle along the avoidance route is started. 
         FIG. 5B  is a view which shows a scene that a departing amount of the own vehicle from the avoidance route after the execution of the avoiding steering process is started, is increased. 
         FIG. 5C  is a view which shows a scene which may occur when the departing amount of the own vehicle from the avoidance route is increased, and the execution of the avoiding steering process or the steering avoidance control is continued. 
         FIG. 6  is a view which shows the departing amount of the own vehicle from the avoidance route. 
         FIG. 7  is a view which shows a relationship between the avoidance route and a steering state. 
         FIG. 8  is a view which shows a time chart which illustrates changes of the departing amount of the own vehicle from the avoidance route, etc. when the execution of the steering avoidance control is terminated, not stopped halfway. 
         FIG. 9  is a view which shows a time chart which illustrates the changes of the departing amount of the own vehicle from the avoidance route, etc. when the execution of the steering avoidance control is stopped halfway. 
         FIG. 10  is a view which shows a flowchart of a routine executed by the vehicle collision avoidance assist apparatus according to the embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Below, a vehicle collision avoidance assist apparatus according to an embodiment of the invention will be described with reference to the drawings. As shown in  FIG. 1 , the vehicle collision avoidance assist apparatus  10  according to the embodiment of the invention is installed on an own vehicle  100 . 
     &lt;ECU&gt; 
     As shown in  FIG. 1 , the vehicle collision avoidance assist apparatus  10  includes an ECU  90 . ECU stands for electronic control unit. The ECU  90  includes a micro-computer as a main component. The micro-computer includes a CPU, a ROM, a RAM, a non-volatile, and an interface. The CPU is configured or programmed to realize various functions by executing instructions, programs, or routines stored in the ROM. 
     &lt;Driving Apparatus, Etc.&gt; 
     Moreover, a driving apparatus  21 , a braking apparatus  22 , and a steering apparatus  23  are installed on the own vehicle  100 . 
     &lt;Driving Apparatus&gt; 
     The driving apparatus  21  is an apparatus which outputs a driving force to be applied to the own vehicle  100  to move the own vehicle  100 . The driving apparatus  21  is, for example, an internal combustion engine and at least one electric motor. The driving apparatus  21  is electrically connected to the ECU  90 . The ECU  90  can control the driving force output from the driving apparatus  21  by controlling an activation of the driving apparatus  21 . 
     &lt;Braking Apparatus&gt; 
     The braking apparatus  22  is an apparatus which outputs a braking force to be applied to the own vehicle  100  to brake the own vehicle  100 . The braking apparatus  22  is, for example, a brake apparatus. The braking apparatus  22  is electrically connected to the ECU  90 . The ECU  90  can control the braking force output from the braking apparatus  22  by controlling an activation of the braking apparatus  22 . 
     &lt;Steering Apparatus&gt; 
     The steering apparatus  23  is an apparatus which outputs a steering force to be applied to the own vehicle  100  to steer the own vehicle  100 . The steering apparatus  23  is, for example, a power steering apparatus. The steering apparatus  23  is electrically connected to the ECU  90 . The ECU  90  can control the steering force output from the steering apparatus  23  by controlling an activation of the steering apparatus  23 . 
     &lt;Sensors, Etc.&gt; 
     Moreover, an accelerator pedal operation amount sensor  61 , a brake pedal operation amount sensor  62 , a steering angle sensor  63 , a steering torque sensor  64 , a vehicle moving speed sensor  65 , a longitudinal acceleration sensor  66 , a lateral acceleration sensor  67 , and a forward information detection apparatus  68 . 
     &lt;Accelerator Pedal Operation Amount Sensor&gt; 
     The accelerator pedal operation amount sensor  61  is electrically connected to the ECU  90 . The accelerator pedal operation amount sensor  61  detects an operation amount of an accelerator pedal  31 . The accelerator pedal operation amount sensor  61  sends information on the detected operation amount to the ECU  90 . The ECU  90  acquires the operation amount of the accelerator pedal  31  as an accelerator pedal operation amount AP, based on the information sent from the accelerator pedal operation amount sensor  61 . The ECU  90  calculates and acquires a requested driving force PDreq, based on the accelerator pedal operation amount AP and a vehicle moving speed V 100  of the own vehicle  100 . The requested driving force PDreq is a driving force requested for the driving apparatus  21  to output. 
     &lt;Brake Pedal Operation Amount Sensor&gt; 
     The brake pedal operation amount sensor  62  is electrically connected to the ECU  90 . The brake pedal operation amount sensor  62  detects an operation amount of a brake pedal  32 . The brake pedal operation amount sensor  62  sends information on the detected operation amount to the ECU  90 . The ECU  90  acquires the operation amount of the brake pedal  32  as a brake pedal operation amount BP, based on the information sent from the brake pedal operation amount sensor  62 . The ECU  90  calculates and acquires a requested braking force PBreq, based on the brake pedal operation amount BP. The requested braking force PBreq is a braking force requested for the braking apparatus  22  to output. 
     &lt;Steering Angle Sensor&gt; 
     The steering angle sensor  63  is electrically connected to the ECU  90 . The steering angle sensor  63  detects a rotation angle of a steering wheel  33  of the own vehicle  100  from a neutral position of the steering wheel  33 . The steering angle sensor  63  sends information on the detected rotation angle to the ECU  90 . The ECU  90  acquires the rotation angle of the steering wheel  33  from the neutral position as a steering angle SA, based on the information sent from the steering angle sensor  63 . 
     &lt;Steering Torque Sensor&gt; 
     The steering torque sensor  64  is electrically connected to the ECU  90 . The steering torque sensor  64  detects a torque which a driver of the own vehicle  100  inputs to a steering shaft  34  via the steering wheel  33 . The steering torque sensor  64  sends information on the detected torque to the ECU  90 . The ECU  90  acquires the torque which the driver inputs to the steering shaft  34  via the steering wheel  33  as a driver input torque TQdr, based on the information sent from the steering torque sensor  64 . 
     &lt;Vehicle Moving Speed Sensor&gt; 
     The vehicle moving speed sensor  65  is electrically connected to the ECU  90 . The vehicle moving speed sensor  65  detects rotation speeds of wheels of the own vehicle  100 . The vehicle moving speed sensor  65  sends information on the detected rotation speeds of the wheels of the own vehicle  100 . The ECU  90  acquires the moving speed of the own vehicle  100  as the vehicle moving speed V 100 , based on the information sent from the vehicle moving speed sensor  65 . 
     In addition, the ECU  90  calculates and acquires a torque to be applied to the steering shaft  34  from the steering apparatus  23  as an assist steering torque TQas, based on the driver input torque TQdr and the vehicle moving speed V 100 . The assist steering torque TQas is a torque applied to the steering shaft  34  to assist a steering operation to the steering wheel  33  carried out by the driver. 
     &lt;Longitudinal Acceleration Sensor&gt; 
     The longitudinal acceleration sensor  66  is electrically connected to the ECU  90 . The longitudinal acceleration sensor  66  detects an acceleration of the own vehicle  100  in a longitudinal direction of the own vehicle  100 . The longitudinal acceleration sensor  66  sends information on the detected acceleration to the ECU  90 . The ECU  90  acquires the acceleration of the own vehicle  100  in the longitudinal direction of the own vehicle  100  as a longitudinal acceleration Gx, based on the information sent from the longitudinal acceleration sensor  66 . 
     &lt;Lateral Acceleration Sensor&gt; 
     The lateral acceleration sensor  67  is electrically connected to the ECU  90 . The lateral acceleration sensor  67  detects an acceleration of the own vehicle  100  in a lateral direction of the own vehicle  100 . The lateral acceleration sensor  67  sends information on the detected acceleration to the ECU  90 . The ECU  90  acquires the acceleration of the own vehicle  100  in the lateral direction of the own vehicle  100  as a lateral acceleration Gy, based on the information sent from the lateral acceleration sensor  67 . 
     &lt;Forward Information Detection Apparatus&gt; 
     The forward information detection apparatus  68  is an apparatus which detects information on a situation ahead of the own vehicle  100 . The forward information detection apparatus  68  includes, for example, at least one camera, at least one radar sensor such as at least one millimeter wave radar, at least one ultrasonic wave sensor such as at least one clearance sonar, and at least one laser radar such as at least one LiDAR. 
     The forward information detection apparatus  68  is electrically connected to the ECU  90 . The forward information detection apparatus  68  detects information on the situation ahead of the own vehicle  100 . The forward information detection apparatus  68  sends the detected information (forward information IF) to the ECU  90 . 
     The ECU  90  can detect an object  200  ahead of the own vehicle  100 , based on the forward information I_F. Moreover, when the ECU  90  detects the object  200 , the ECU  90  can acquire an object distance D 200 , a relative moving speed dV, and a moving direction of the object  200 , based on the forward information I_F. The object distance D 200  is a distance between the object  200  and the own vehicle  100 . The relative moving speed dV is a relative moving speed of the own vehicle  100  with respect to the object  200 . In addition, the ECU  90  can recognize a left lane marking LML and a right lane marking LMR (see  FIG. 2A ) which define an own vehicle moving lane LN, based on the forward information I_F. The own vehicle moving lane LN is a moving lane of the own vehicle  100 . Otherwise, the ECU  90  can recognize an end of a road on which the own vehicle  100  moves, based on the forward information IF. That is, the ECU  90  can recognize a road end, based on the forward information I_F. 
     Then, the ECU  90  acquires a yaw angle YA, based on the recognized left and right lane markings LML and LMR or the recognized road end. As shown in  FIG. 2B  and  FIG. 2C , the yaw angle YA is an angle between an own vehicle moving lane extending direction line LLN and an own vehicle longitudinal extending center line L 100 . The own vehicle moving lane extending direction line LLN is a line which represents an extending direction of the own vehicle moving lane LN. The own vehicle longitudinal extending center line L 100  is a line which extends through a center of a width of the own vehicle  100  in the longitudinal direction of the own vehicle  100 . 
     &lt;Summary of Operations of Vehicle Collision Avoidance Assist Apparatus&gt; 
     Next, a summary of operations of the vehicle collision avoidance assist apparatus  10  will be described. While the own vehicle  100  moves, the vehicle collision avoidance assist apparatus  10  determines, based on the forward information I_F, whether there is an object ahead of the own vehicle  100 . In this embodiment, the object is a vehicle, a person, a bicycle, or a guard rail. 
     When there is an object ahead of the own vehicle  100 , and a probability that the own vehicle  100  collides with the object has been increased to a high level, the vehicle collision avoidance assist apparatus  10  determines whether there is space at the side of the object where the own vehicle  100  can move and avoid the object. When there is the space, the vehicle collision avoidance assist apparatus  10  executes a steering avoidance control of steering the own vehicle  100  to avoid the object, using the space. 
     It should be noted that the vehicle collision avoidance assist apparatus  10  may be configured to execute an alerting process of informing the driver of the own vehicle  100  that the own vehicle  100  may collide with the object before the vehicle collision avoidance assist apparatus  10  starts an execution of the steering avoidance control. In this case, when the driver does not carry out an operation of avoiding the collision of the own vehicle  100  with the object such as an operation to the accelerator pedal  31 , an operation to the brake pedal  32 , and an operation to the steering wheel  33  even by executing the alerting process, the vehicle collision avoidance assist apparatus  10  executes a forcibly braking process of forcibly braking the own vehicle  100  to stop the own vehicle  100 . In this case, when the own vehicle  100  probably collides with the object even by executing the forcibly braking process, the vehicle collision avoidance assist apparatus  10  executes the steering avoidance control. 
     Further, the vehicle collision avoidance assist apparatus  10  executes a normal moving control when there is no object ahead of the own vehicle  100  or when there is the object ahead of the own vehicle  100  but the vehicle collision avoidance assist apparatus  10  predicts that the own vehicle  100  does not collide with the object. The normal moving control is a control of controlling the activation of the driving apparatus  21  to cause the driving apparatus  21  to output the driving force corresponding to the requested driving force PDreq when the requested driving force PDreq is greater than zero. In addition, the normal moving control is a control of controlling the activation of the braking apparatus  22  to cause the braking apparatus  22  to output the braking force corresponding to the requested braking force PBreq when the requested braking forc&#39;e PBreq is greater than zero. In addition, the normal moving control is a control of controlling the activation of the steering apparatus  23  to cause the steering apparatus  23  to output the steering torque corresponding to the assist steering torque TQas when the assist steering torque TQas is greater than zero. 
     &lt;Steering Avoidance Control&gt; 
     Next, the steering avoidance control will be described. 
     While the own vehicle  100  moves, the vehicle collision avoidance assist apparatus  10  determines, based on the forward information I_F, whether there is an object  200  in an own vehicle moving area A 100 . As shown in  FIG. 3A , the own vehicle moving area A 100  is an area which has (i) a center line corresponding to a moving route R 100  of the own vehicle  100  and (ii) a width equal to the width of the own vehicle  100 . The moving route R 100  of the own vehicle  100  is a route along which the own vehicle  100  predictively moves assuming that the own vehicle  100  moves with maintaining the current steering angle SA. 
     When the vehicle collision avoidance assist apparatus  10  determines that there is the object  200  in the own vehicle moving area A 100 , the vehicle collision avoidance assist apparatus  10  acquires an object distance D 200  and a relative moving speed dV. The object distance D 200  is a distance between the object  200  and the own vehicle  100 . The relative moving speed dV is a moving speed of the own vehicle  100  with respect to the object  200 . Then, the vehicle collision avoidance assist apparatus  10  calculates and acquires a predicted reaching time TTC by dividing the object distance D 200  by the relative moving speed dV (TTC=D 200 /dV). The predicted reaching time TTC is a time which the own vehicle  100  predictively takes to reach the object  200 . While the vehicle collision avoidance assist apparatus  10  determines that there is the object  200  in the own vehicle moving area A 100 , the vehicle collision avoidance assist apparatus  10  acquires the predicted reaching time TTC with a predetermined calculation cycle CYC. 
     When the relative moving speed dV is constant, the predicted reaching time TTC decreases as the object distance D 200  decreases. As shown in  FIG. 3B , when the own vehicle  100  approaches the object  200 , and the predicted reaching time TTC decreases to a predetermined time (this predetermined time will be hereinafter referred to as “predetermined predicted reaching time TTCth”), the vehicle collision avoidance assist apparatus  10  determines that a steering avoiding condition becomes satisfied. That is, when (i) the vehicle collision avoidance assist apparatus  10  acquires the predicted reaching time TTC as an index value which represents the probability that the own vehicle  100  collides with the object  200 , and z(ii) the index value becomes equal to or greater than a predetermined index value, the vehicle collision avoidance assist apparatus  10  determines that the probability that the own vehicle  100  collides with the object has increased to a high level. Thus, in this embodiment, the index value which represents the probability that the own vehicle  100  collides with the object  200  increases as the predicted reaching time TTC decreases. 
     When the steering avoiding condition becomes satisfied, the vehicle collision avoidance assist apparatus  10  starts executing the steering avoidance control. When the vehicle collision avoidance assist apparatus  10  starts executing the steering avoidance control, the vehicle collision avoidance assist apparatus  10  determines whether the driver operates the steering wheel  33  so as to cause the own vehicle  100  to pass by the object  200 . 
     When the vehicle collision avoidance assist apparatus  10  determines that the driver operates the steering wheel  33  so as to move the own vehicle  100  to avoid the object  200 , as shown in  FIG. 3C , the vehicle collision avoidance assist apparatus  10  sets a recommended avoidance route Rrec. The recommended avoidance route Rrec is a route recommended to move the own vehicle  100  to avoid the object  200 . 
     In this embodiment, the vehicle collision avoidance assist apparatus  10  sets, as the recommended avoidance route Rrec, a route to move the own vehicle  100  in the own vehicle moving lane LN and avoid the object  200 . In other words, the vehicle collision avoidance assist apparatus  10  sets, as the recommended avoidance route Rrec, a route to move the own vehicle  100  and avoid the object  200 , preventing the own vehicle  100  from moving out of the own vehicle moving lane LN. 
     Further, in order to avoid the collision of the own vehicle  100  with the object  200  by forcibly steering the own vehicle  100  to move the own vehicle  100  along the recommended avoidance route Rrec, the vehicle collision avoidance assist apparatus  10  should set the recommended avoidance route Rrec, depending on the relative moving speed dV of the own vehicle  100  with respect to the object  200 . Accordingly, the vehicle collision avoidance assist apparatus  10  is configured to set the recommended avoidance route Rrec in consideration of the relative moving speed dV of the own vehicle  100  with respect to the object  200 . 
     Further, in this embodiment, the vehicle collision avoidance assist apparatus  10  sets the recommended avoidance route Rrec, depending on the operation applied to the steering wheel  33  by the driver. In particular, when the driver rotates the steering wheel  33  clockwise, the vehicle collision avoidance assist apparatus  10  sets, as the recommended avoidance route Rrec, a route passing the right side of the object  200 . On the other hand, when the driver rotates the steering wheel  33  counterclockwise, the vehicle collision avoidance assist apparatus  10  sets, as the recommended avoidance route Rrec, a route passing the left side of the object  200 . 
     After the vehicle collision avoidance assist apparatus  10  sets the recommended avoidance route Rrec, the vehicle collision avoidance assist apparatus  10  executes a process of steering the own vehicle  100  by increasing and decreasing the assist steering torque TQas, depending on the driver input torque TQdr so as to move the own vehicle  100  within a predetermined distance Dy from the recommended avoidance route Rrec. Hereinafter, this process of steering the own vehicle  100  will be referred to as “first avoiding steering process” or “assist steering process”. Thus, after the vehicle collision avoidance assist apparatus  10  sets the recommended avoidance route Rrec, the vehicle collision avoidance assist apparatus  10  executes the first avoiding steering process of controlling the assist steering torque TQas so as to move the own vehicle  100  within the predetermined distance Dy from the recommended avoidance route Rrec. Thus, the first avoiding steering process is realized by controlling the assist steering torque TQas in consideration of the driver input torque TQdr. 
     It should be noted that the vehicle collision avoidance assist apparatus  10  may be configured to decelerate the own vehicle  100  by decreasing the driving force applied to the own vehicle  100  or limiting the driving force applied to the own vehicle  100  to a certain value or less or applying the braking force to the own vehicle  100  in addition to executing the first avoiding steering process. 
     On the other hand, when the vehicle collision avoidance assist apparatus  10  determines that the driver does not operate the steering wheel  33  to cause the own vehicle  100  to avoid the object  200  when (i) the steering avoiding condition becomes satisfied, and (ii) the vehicle collision avoidance assist apparatus  10  starts executing the steering avoidance control, as shown in  FIG. 3D , the vehicle collision avoidance assist apparatus  10  sets a target avoidance route Rtgt to move the own vehicle  100  to avoid the object  200 . 
     In this embodiment, the vehicle collision avoidance assist apparatus  10  sets, as the target avoidance route Rtgt, a route to move the own vehicle  100  in the own vehicle moving lane LN and avoid the object  200 . In other words, the vehicle collision avoidance assist apparatus  10  sets, as the target avoidance route Rtgt, a route to move the own vehicle  100  and avoid the object  200 , preventing the own vehicle  100  from moving out of the own vehicle moving lane LN. 
     Further, in order to avoid the collision of the own vehicle  100  with the object  200  by forcibly steering the own vehicle  100  to move the own vehicle  100  along the target avoidance route Rtgt, the vehicle collision avoidance assist apparatus  10  should set the target avoidance route Rtgt, depending on the relative moving speed dV of the own vehicle  100  with respect to the object  200 . Accordingly, the vehicle collision avoidance assist apparatus  10  is configured to set the target avoidance route Rtgt in consideration of the relative moving speed dV of the own vehicle  100  with respect to the object  200 . 
     After the vehicle collision avoidance assist apparatus  10  sets the target avoidance route Rtgt, the vehicle collision avoidance assist apparatus  10  executes a process of steering the own vehicle  100  by controlling the assist steering torque TQas to move the own vehicle  100  along the target avoidance route Rtgt. Hereinafter, this process of steering the own vehicle  100  will be referred to as “second avoiding steering process” or “autonomous steering process”. Thus, the second avoiding steering process is realized by controlling the assist steering torque TQas without considering the driver input torque TQdr. 
     It should be noted that the vehicle collision avoidance assist apparatus  10  may be configured to decelerate the own vehicle  100  by decreasing the driving force applied to the own vehicle  100  or limiting the driving force applied to the own vehicle  100  to a certain value or less or applying the braking force to the own vehicle  100  in addition to executing the second avoiding steering process. 
     When (i) the avoidance route R (i.e., the recommended avoidance route Rrec or the target avoidance route Rtgt) is set as shown in  FIG. 4A , and (ii) an execution of the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) is started, the own vehicle  100  is steered to move along the avoidance route R as shown in  FIG. 4B , and avoids the collision with the object  200  as shown in  FIG. 4C . 
     It should be noted that the vehicle collision avoidance assist apparatus  10  does not execute the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) when (i) the width of the own vehicle moving lane LN is narrow and thus, there is no space to move the own vehicle  100  to avoid the object  200  at the side of the object  200  and thus, (ii) the vehicle collision avoidance assist apparatus  10  cannot set the recommended avoidance route Rrec or the target avoidance route Rtgt. Also, the vehicle collision avoidance assist apparatus  10  does not execute the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) when (i) the vehicle collision avoidance assist apparatus  10  does not recognize the left lane marking LML at the left side of the own vehicle  100  or the right lane marking LMR at the right side of the own vehicle  100  and thus, (ii) the vehicle collision avoidance assist apparatus  10  cannot set the recommended avoidance route Rrec or the target avoidance route Rtgt. That is, when a forbidding condition that the recommended avoidance route Rrec or the target avoidance route Rtgt cannot be set, is satisfied, the vehicle collision avoidance assist apparatus  10  does not execute the avoiding steering process. 
     It should be noted that one or more of conditions C 1  to C 21  below may be used as the forbidding condition. 
     A condition C 1  is a condition that the vehicle collision avoidance assist apparatus  10  cannot realize the avoiding steering process (the first avoiding steering process of the second avoiding steering process) due to a fact that devices such as the steering apparatus  23  used to realize the avoiding steering process are malfunctioned. 
     A condition C 2  is a condition that when the vehicle collision avoidance assist apparatus  10  is configured to execute an autonomous brake control (PCS), the vehicle collision avoidance assist apparatus  10  cannot realize the autonomous brake control due to a fact that devices such as the braking apparatus  22  used to realize the autonomous brake control are malfunctioned. The autonomous brake control is a control of stopping the own vehicle  100  by forcibly braking the own vehicle  100  before the own vehicle  100  collides with the object ahead of the own vehicle  100  when the probability that the own vehicle  100  collides with the object ahead of the own vehicle  100  has increased to a high level. 
     A condition C 3  is a condition that when the vehicle collision avoidance assist apparatus  10  is configured to execute a sideslip prevention control (VSC), the vehicle collision avoidance assist apparatus  10  cannot realize the sideslip prevention control due to a fact that devices such as the braking apparatus  22  used to realize the sideslip prevention control are malfunctioned. The sideslip prevention control is, for example, a control of stabilizing a moving behavior of the own vehicle  100  by adjusting the driving force PD applied to the own vehicle  100  or individually adjusting the braking forces PB applied to wheels of the own vehicle  100 , respectively when the moving behavior of the own vehicle  100  becomes unstable due to steering the own vehicle  100 . 
     A condition C 4  is a condition that when the vehicle collision avoidance assist apparatus  10  is configured to execute the autonomous brake control (PCS), the vehicle collision avoidance assist apparatus  10  can stop the own vehicle  100  by the autonomous brake control before the own vehicle  100  collides with the object  200 . 
     A condition C 5  is a condition that when (i) the vehicle collision avoidance assist apparatus  10  is configured to execute the autonomous brake control (PCS), and (ii) the vehicle collision avoidance assist apparatus  10  starts executing the autonomous brake control and then, terminates executing the autonomous brake control, a time elapsing since the vehicle collision avoidance assist apparatus  10  terminates executing the autonomous brake control is equal to or shorter than a predetermined time. 
     A condition C 6  is a condition that when the vehicle collision avoidance assist apparatus  10  starts executing the steering avoidance control and then, the vehicle collision avoidance assist apparatus  10  terminates executing the steering avoidance control, a time elapsing since the vehicle collision avoidance assist apparatus  10  terminates executing the steering avoidance control is equal to or shorter than a predetermined time. 
     A condition C 7  is a condition that the vehicle collision avoidance assist apparatus  10  activates or blinks turn signals of the own vehicle  100 . 
     A condition C 8  is a condition that when (i) the object  200  is a preceding vehicle, and (ii) the recommended avoidance route Rrec or the target avoidance route Rtgt is a route passing at the left side of the preceding vehicle, left turn signals of the preceding vehicle are activated or blinked. The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information I_F, whether the left turn signals of the preceding vehicle are activated or blinked. It should be noted that the preceding vehicle is a vehicle which moves ahead of the own vehicle  100  in the own vehicle moving lane LN or the moving lane of the own vehicle  100  in the same direction as the moving direction of the own vehicle  100 . 
     A condition C 9  is a condition that when (i) the object  200  is the preceding vehicle, and (ii) the recommended avoidance route Rrec or the target avoidance route Rtgt is a route passing at the right side of the preceding vehicle, right turn signals of the preceding vehicle are activated or blinked. The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information I_F, whether the right turn signals of the preceding vehicle are activated or blinked. 
     A condition C 10  is a condition that the accelerator pedal operation amount AP is equal to or greater than a predetermined accelerator pedal operation amount APth. 
     A condition C 11  is a condition that the brake pedal operation amount BP is equal to or greater than a predetermined brake pedal operation amount BPth. 
     A condition C 12  is a condition that the vehicle moving speed V 100  of the own vehicle  100  is not within a predetermined range Rv. 
     A condition C 13  is a condition that the relative moving speed dV of the object  200  with respect to the own vehicle  100  is not within a predetermined range Rdv. 
     A condition C 14  is a condition that the lateral acceleration Gy is equal to or greater than a predetermined lateral acceleration Gy_th. 
     A condition C 15  is a condition that the longitudinal acceleration Gx is a positive value, and an absolute value of the longitudinal acceleration Gx is equal to or greater than a predetermined value Gx_th. 
     A condition C 16  is a condition that the longitudinal acceleration Gx is a negative value, and the absolute value of the longitudinal acceleration Gx is equal to or greater than the predetermined value Gx_th. 
     A condition C 17  is a condition that the own vehicle  100  moves along a curving road. The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information IF, whether the own vehicle  100  moves along the curving road. 
     A condition C 18  is a condition that a lane-markings distance is equal to or longer than a predetermined distance. The lane-markings distance is a distance between the left lane marking LML at the left side of the own vehicle  100  and the right lane marking LMR at the right side of the own vehicle  100 . The vehicle collision avoidance assist apparatus  10  can acquire the lane-markings distance, based on the forward information I_F. 
     A condition C 19  is a condition that the recommended avoidance route Rrec or the target avoidance route Rtgt crosses a longitudinally-extending center line of the object  200 . The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information IF, whether the recommended avoidance route Rrec or the target avoidance route Rtgt crosses the longitudinally-extending center line of the object  200 . 
     A condition C 20  is a condition that the object  200  moves, crossing the recommended avoidance route Rrec or the target avoidance route Rtgt. The vehicle collision avoidance assist apparatus  10  can determine, based on the forward information I_F, whether the object  200  moves, crossing the recommended avoidance route Rrec or the target avoidance route Rtgt. 
     A condition C 21  is a condition that the vehicle collision avoidance assist apparatus  10  can set the recommended avoidance route Rrec or the target avoidance route Rtgt but the vehicle collision avoidance assist apparatus  10  predicts that the vehicle collision avoidance assist apparatus  10  cannot move the own vehicle  100  along the recommended avoidance route Rrec or the target avoidance route Rtgt. 
     &lt;Termination of Execution of Steering Avoidance Control&gt; 
     After the vehicle collision avoidance assist apparatus  10  starts executing the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), the vehicle collision avoidance assist apparatus  10  monitors whether a terminating condition becomes satisfied. The terminating condition is a condition that an absolute value of the yaw angle YA becomes equal to or smaller than a predetermined yaw angle YAth. The vehicle collision avoidance assist apparatus  10  continues executing the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) as far as the terminating condition is not satisfied. On the other hand, when the terminating condition becomes satisfied, the vehicle collision avoidance assist apparatus  10  terminates executing the avoiding steering process or the steering avoidance control. 
     It should be noted that when the vehicle collision avoidance assist apparatus  10  is configured to execute the steering avoidance control and brake and stop the own vehicle  100 , the vehicle collision avoidance assist apparatus  10  may be configured to terminate executing the steering avoidance control or the avoiding steering process when the own vehicle  100  stops. 
     &lt;Stop of Execution of Steering Avoidance Control&gt; 
     After the vehicle collision avoidance assist apparatus  10  sets the avoidance route R (i.e., the recommended avoidance route Rrec or the target avoidance route Rtgt) and starts executing the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) as shown in  FIG. 5A , the own vehicle  100  may be deviated or departed from the avoidance route R as shown in  FIG. 5B . If the own vehicle  100  is considerably departed from the avoidance route R, and the execution of the avoiding steering process is continued, the own vehicle  100  may collide with the target object  200   tgt  as shown in  FIG. 5C . 
     Accordingly, after the vehicle collision avoidance assist apparatus  10  starts executing the avoiding steering process, the vehicle collision avoidance assist apparatus  10  acquires a departing amount dD of the own vehicle  100  from the avoidance route R, based on the forward information I_F. When the departing amount dD becomes equal to or greater than a predetermined departing amount dDth, the vehicle collision avoidance assist apparatus  10  stops executing the steering avoidance control. 
     In this embodiment, as shown in  FIG. 6 , the departing amount dD of the own vehicle  100  is a distance between a tangential line LR and the own vehicle longitudinal extending center line L 100 . The tangential line LR is a tangential line at a point on the avoidance route R which corresponds to a current position of the own vehicle  100 .  FIG. 6  shows the departing amount dD when the own vehicle  100  is departed from the avoidance route R toward the target object  200   tgt . In this regard, also when the own vehicle  100  is departed from the avoidance route R opposite to the target object  200   tgt , the vehicle collision avoidance assist apparatus  10  acquires, as the departing amount dD, a distance between (i) the tangential line LR at the point on the avoidance route R which corresponds to the current position of the own vehicle  100  and (ii) the own vehicle longitudinal extending center line L 100 . 
     Further, in this embodiment, the predetermined departing amount dDth is set as described below, depending on a steering state of the own vehicle  100  while the avoiding steering process of the steering avoidance control is executed. As shown in  FIG. 7 , while the avoiding steering process is executed, the steering state changes in order of an avoiding steering state, an avoiding steering keeping state, a return steering state, a return steering keeping state, and an adjusting steering state. The avoiding steering state is a state of increasing the steering angle SA of the own vehicle  100  to turn the own vehicle  100  right or left to make a situation that the target object  200   tgt  is not in the own vehicle moving area A 100 . The avoiding steering keeping state is a state of keeping the steering angle SA which has been increased in the avoiding steering state. The return steering state is a state of decreasing the steering angle SA to make a situation that the own vehicle longitudinal extending center line L 100  is parallel to the own vehicle moving lane extending line LLN. The return steering keeping state is a state of keeping the steering angle SA which has been decreased in the return steering state. The adjusting steering state is a state of increasing and decreasing the steering angle SA to adjust the steering angle SA to make a situation that the own vehicle longitudinal extending center line L 100  is parallel to the own vehicle moving lane extending line LLN. 
     Then, the vehicle collision avoidance assist apparatus  10  sets a first departing amount dD 1  as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is moved in an avoiding steering section of the avoidance route R in which the steering state is the avoiding steering state. Also, the vehicle collision avoidance assist apparatus  10  sets the first departing amount dD 1  as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is moved in a return steering section of the avoidance route R in which the steering state is the return steering state. On the other hand, the vehicle collision avoidance assist apparatus  10  sets a second departing amount dD 2  smaller than the first departing amount dD 1  as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is moved in an avoiding steering keeping section of the avoidance route R in which the steering state is the avoiding steering keeping state. Also, the vehicle collision avoidance assist apparatus  10  sets the second departing amount dD 2  as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is moved in a return steering keeping section of the avoidance route R in which the steering state is the return steering keeping state. Also, the vehicle collision avoidance assist apparatus  10  sets the second departing amount dD 2  as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is moved in an adjusting steering section of the avoidance route R in which the steering state is the adjusting steering state. 
     When the own vehicle  100  is moved in the avoiding steering section of the avoidance route R, the first departing amount dD 1  to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R toward the target object  200   tgt , may be set to a smaller value than the first departing amount dD 1  to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R opposite to the target object  200   tgt . In this case, when the own vehicle  100  is moved in the avoiding steering section of the avoidance route R, the first departing amount dD 1  set as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R in an opposite direction to a turning direction of the own vehicle  100  achieved by the avoiding steering process, is set to a smaller value than the first departing amount dD 1  set as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R in the same direction as the turning direction of the own vehicle  100  achieved by the avoiding steering process. 
     Further, when the own vehicle  100  is moved in the avoiding steering keeping section of the avoidance route R, the second departing amount dD 2  to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R toward the target object  200   tgt , may be set to a smaller value than the second departing amount dD 2  to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R opposite to the target object  200   tgt . In this case, when the own vehicle  100  is moved in the avoiding steering keeping section of the avoidance route R, the second departing amount dD 2  set as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R in the opposite direction to the turning direction of the own vehicle  100  achieved by the avoiding steering process, is set to a smaller value than the second departing amount dD 2  set as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R in the same direction as the turning direction of the own vehicle  100  achieved by the avoiding steering process. 
     Furthermore, when the own vehicle  100  is moved in the return steering section of the avoidance route R, the first departing amount dD 1  to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R opposite to the target object  200   tgt , may be set to a smaller value than the first departing amount dD 1  to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R toward to the target object  200   tgt . In this case, when the own vehicle  100  is moved in the return steering section of the avoidance route R, the first departing amount dD 1  set as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R in the opposite direction to the turning direction of the own vehicle  100  achieved by the avoiding steering process, is set to a smaller value than the first departing amount dD 1  set as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R in the same direction as the turning direction of the own vehicle  100  achieved by the avoiding steering process. 
     Furthermore, when the own vehicle  100  is moved in the return steering keeping section of the avoidance route R, the second departing amount dD 2  to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R opposite to the target object  200   tgt , may be set to a smaller value than the second departing amount dD 2  to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R toward the target object  200   tgt . In this case, when the own vehicle  100  is moved in the return steering keeping section of the avoidance route R, the second departing amount dD 2  set as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R in the opposite direction to the turning direction of the own vehicle  100  achieved by the avoiding steering process, is set to a smaller value than the second departing amount dD 2  set as the predetermined departing amount dDth to be compared with the departing amount dD when the own vehicle  100  is departed from the avoidance route R in the same direction as the turning direction of the own vehicle  100  achieved by the avoiding steering process. 
     Thus, when the departing amount dD of the own vehicle  100  does not become equal to or greater than the predetermined departing amount dDth until a terminating condition becomes satisfied after the execution of the avoiding steering process is started, as shown in  FIG. 8 , the vehicle collision avoidance assist apparatus  10  terminates executing the steering avoidance control when the terminating condition becomes satisfied. 
     In an example shown in  FIG. 8 , at a point of time t 80 , the steering avoidance condition becomes satisfied. Thus, the execution of the steering avoidance control is started, and the steering state becomes the avoiding steering state by the avoiding steering process. While the steering state is the avoiding steering state, the predetermined departing amount dDth is set to the first departing amount dD 1 . 
     In the example shown in  FIG. 8 , when the steering state becomes the avoiding steering state at the point of time t 80 , the departing amount dD of the own vehicle  100  is increased. In this example, the departing amount dD is kept smaller than the first departing amount dD 1 . Thus, the execution of the avoiding steering process is continued. 
     Then, at a point of time t 81 , the steering state becomes the avoiding steering keeping state. Then, at a point of time t 82 , the steering state becomes the return steering state. While the steering state is the avoiding steering keeping state from the point of time t 81  to the point of time t 82 , the predetermined departing amount dDth is set to the second departing amount dD 2  smaller than the first departing amount dD 1 . In this example, the departing amount dD of the own vehicle  100  is kept smaller than the second departing amount dD 2 . Thus, the execution of the avoiding steering process is continued. 
     Then, after the steering state becomes the return steering state at the point of time t 82 , the steering state becomes the return steering keeping state at a point of time t 83 . While the steering state is the return steering state from the point of time t 82  to the point of time t 83 , the predetermined departing amount dDth is set to the first departing amount dD 1 . In this example, the departing amount dD of the own vehicle  100  is kept smaller than the first departing amount dD 1 . Thus, the execution of the avoiding steering process is continued. 
     Then, after the steering state becomes the return steering keeping state at the point of time t 83 , the steering state becomes the adjusting steering state at a point of time t 84 . While the steering state is the return steering keeping state from the point of time t 83  to the point of time t 84 , the predetermined departing amount dDth is set to the second departing amount dD 2  smaller than the first departing amount dD 1 . In this example, the departing amount dD of the own vehicle  100  is kept smaller than the second departing amount dD 2 . Thus, the execution of the avoiding steering process is continued. 
     Then, after the steering state becomes the adjusting steering state at the point of time t 84 , the predetermined departing amount dDth is set to the second departing amount dD 2 . In this example, the departing amount dD of the own vehicle  100  is kept smaller than the second departing amount dD 2 . Thus, the execution of the avoiding steering process is continued. 
     Then, when the terminating condition becomes satisfied at a point of time t 85 , the execution of the steering avoidance control is terminated. 
     On the other hand, when the execution of the avoiding steering process is started, and the departing amount dD of the own vehicle  100  becomes equal to or greater than the predetermined departing amount dDth before the terminating condition becomes satisfied, as shown in  FIG. 9 , the vehicle collision avoidance assist apparatus  10  stops executing the steering avoidance control. That is, when a stopping condition that the execution of the avoiding steering process is started, and the departing amount dD of the own vehicle  100  becomes equal to or greater than the predetermined departing amount dDth before the terminating condition becomes satisfied, becomes satisfied, the vehicle collision avoidance assist apparatus  10  stops executing the steering avoidance control. 
     In an example shown in  FIG. 9 , at the point of time t 90 , the steering avoidance condition becomes satisfied. Thus, the execution of the steering avoidance control is started, and the steering state becomes the avoiding steering state by the avoiding steering process. While the steering state is the avoiding steering state, the predetermined departing amount dDth is set to the first departing amount dD 1 . 
     Also, in the example shown in  FIG. 9 , the steering state becomes the avoiding steering state at the point of time t 90 , and the departing amount dD of the own vehicle  100  is increased. In this example, the departing amount dD of the own vehicle  100  is kept smaller than the first departing amount dD 1 . Thus, the execution of the avoiding steering process is continued. 
     Then, at a point of time t 91 , the steering state becomes the avoiding steering keeping state. Then, at a point of time t 92 , the steering state becomes the return steering state. While the steering state is the avoiding steering keeping state from the point of time t 91  to the point of time t 92 , the predetermined departing amount dDth is set to the second departing amount dD 2  smaller than the first departing amount dD 1 . In this example, the departing amount dD of the own vehicle  100  is kept smaller than the second departing amount dD 2 . Thus, the execution of the avoiding steering process is continued. 
     Then, when the steering state becomes the return steering state, the predetermined departing amount dDth is set to the first departing amount dD 1 . Then, at a point of time t 93 , the departing amount dD of the own vehicle  100  reaches the first departing amount dD 1 , and the stopping condition becomes satisfied. Thus, the execution of the steering avoidance control is stopped. 
     Effects 
     As described above, the avoidance route R is set, and the execution of the avoiding steering process is started. Thereafter, if the own vehicle  100  is considerably departed from the avoidance route R, and the execution of the avoiding steering process is continued, the own vehicle  100  may collide with the object. With the vehicle collision avoidance assist apparatus  10 , when the departing amount dD becomes equal to or greater than the predetermined departing amount dDth, the execution of the steering avoidance control is stopped. Thereby, the collision of the own vehicle  100  with the object  200  can be prevented when the own vehicle  100  is considerably departed from the avoidance route R. 
     Further, while the own vehicle  100  is moved along the avoidance route R by the avoiding steering process, the steering angle SA of the own vehicle  100  is increased, decreased, or kept. When the own vehicle  100  is properly moved by the avoiding steering process, the departing amount dD of the own vehicle  100  from the avoidance route R with the steering angle SA of the own vehicle  100  being increased and decreased, tends to be greater than the departing amount dD of the own vehicle  100  from the avoidance route R with the steering angle SA of the own vehicle  100  being kept. That is, even when the own vehicle  100  is properly moved by the avoiding steering process, the departing amount dD varies, depending on which section of the avoidance route R the own vehicle  100  is moved. Thus, if the predetermined departing amount dDth is set to a fixed value, independently of whether the steering angle SA of the own vehicle  100  being increased, decreased or kept by the avoiding steering process, the execution of the steering avoidance control is not stopped even when the execution of the steering avoidance control should be stopped, or the execution of the steering avoidance control is stopped even when the execution of the steering avoidance control should not be stopped. With the vehicle collision avoidance assist apparatus  10 , the predetermined departing amount dDth is set for each of the sections of the avoidance route R, i.e., the avoiding steering section, the avoiding steering keeping section, the return steering section, the return steering keeping section, and the adjusting steering section. Thereby, whether to stop executing the execution of the steering avoidance control can be appropriately determined. 
     It should be noted that the vehicle collision avoidance assist apparatus  10  may be configured to stop executing the steering avoidance control when the driver input torque TQdr becomes equal to or greater than a relatively great predetermined torque TQth while the vehicle collision avoidance assist apparatus  10  executes the steering avoidance control. 
     &lt;Specific Operations of Vehicle Collision Avoidance Assist Apparatus&gt; 
     Next, specific operations of the vehicle collision avoidance assist apparatus  10  will be described. The CPU of the ECU  90  of the vehicle collision avoidance assist apparatus  10  is configured or programmed to execute a routine shown in  FIG. 10  each time a predetermined time elapses. Thus, at a predetermined timing, the CPU starts executing a process from a step  1000  of the routine shown in  FIG. 10  and proceeds with the process to a step  805  to determine whether a value of a steering avoiding condition flag Xst is “1”. The value of the steering avoiding condition flag Xst is set to “1” when the steering avoiding condition becomes satisfied. 
     When the CPU determines “Yes” at the step  1005 , the CPU proceeds with the process to a step  1010  to determine whether the driver input torque TQdr is greater than zero. When the CPU determines “Yes” at the step  1010 , the CPU proceeds with the process to a step  1015  to set the recommended avoidance route Rrec. Then, the CPU proceeds with the process to a step  1020  to determine whether the CPU has set the recommended avoidance route Rrec. 
     When the CPU determines “Yes” at the step  1020 , the CPU proceeds with the process to a step  1025  to start executing the first avoiding steering process. Then, the CPU proceeds with the process to a step  1045 . On the other hand, when the CPU determines “No” at the step  1020 , the CPU proceeds with the process directly to the step  1045 . In this case, the execution of the first avoiding steering process is not started. 
     Further, when the CPU determines “No” at the step  1010 , the CPU proceeds with the process to a step  1030  to set the target avoidance route Rtgt. Then, the CPU proceeds with the process to a step  1035  to determine whether the CPU has set the target avoidance route Rtgt. When the CPU determines “Yes” at the step  1035 , the CPU proceeds with the process to a step  1040  to start executing the second avoiding steering process. Then, the CPU proceeds with the process to the step  1045 . On the other hand, when the CPU determines “No” at the step  1035 , the CPU proceeds with the process directly to the step  1045 . In this case, the execution of the second avoiding steering process is not started. 
     When the CPU proceeds with the process to the step  1045 , the CPU sets the value of the steering avoiding condition flag Xst to “0”. Then, the CPU proceeds with the process to a step  1050 . 
     Further, when the CPU determines “No” at the step  1005 , the CPU proceeds with the process directly to the step  1050 . 
     When the CPU proceeds with the process to the step  1050 , the CPU determines whether the stopping condition becomes satisfied. When the CPU determines “Yes” at the step  1050 , the CPU proceeds with the process to a step  1055 . At the step  1055 , when the CPU executes the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), the CPU stops executing the steering avoidance control by stopping executing the avoiding steering process. Then, the CPU proceeds with the process to a step  1060 . On the other hand, when the CPU determines “No” at the step  1050 , the CPU proceeds with the process directly to the step  1060 . At this time, when the CPU executes the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), the CPU continues executing the avoiding steering process. 
     When the CPU proceeds with the process to the step  1060 , the CPU determines whether the terminating condition becomes satisfied. When the CPU determines “Yes” at the step  1060 , the CPU proceeds with the process to a step  1065 . At the step  1065 , when the CPU executes the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process), the CPU terminates executing the steering avoidance control by terminating executing the avoiding steering process. Then, the CPU proceeds with the process to a step  1095  to terminate executing the process of this routine once. On the other hand, when the CPU determines “No” at the step  1060 , the CPU proceeds with the process directly to the step  1095  to terminate executing the process of this routine once. At this time, when the avoiding steering process (i.e., the first avoiding steering process or the second avoiding steering process) is executed, the execution of the avoiding steering process is continued. 
     The specific operations of the vehicle collision avoidance assist apparatus  10  have been described. 
     It should be noted that the invention is not limited to the aforementioned embodiments, and various modifications can be employed within the scope of the invention.