Patent Publication Number: US-2022227359-A1

Title: Vehicle control apparatus

Description:
BACKGROUND 
     Field 
     The invention relates to a vehicle control apparatus which is configured to execute a collision avoiding control. 
     Description of the Related Art 
     There is known a vehicle control apparatus which is configured to detect objects around an own vehicle and execute a collision avoiding control of avoiding collision of the own vehicle with the objects (for example, see JP 2018-156253 A). It should be noted that the collision avoiding control is also referred to as pre-crash safety control (Pre-Crash Safety Control). 
     Hereinafter, the vehicle is regulated to move on the left side of a road. The known apparatus described in JP 2018-156253 A executes the collision avoiding control when (i) the own vehicle is turning right in a traffic intersection, and (ii) the known apparatus determines that the own vehicle is going to collide with the object such as an oncoming vehicle. 
     When the own vehicle is turning right in the traffic intersection, situations (1) and (2) described below may occur. 
     (1) The oncoming vehicle passes the traffic intersection earlier than the own vehicle. That is, the own vehicle passes behind the oncoming vehicle. 
     (2) The own vehicle passes the traffic intersection earlier than the oncoming vehicle. That is, the own vehicle passes in front of the oncoming vehicle. 
     In the situations (1) and (2), the own vehicle moves near the oncoming vehicle but does not collide with the oncoming vehicle. However, the known apparatus may determine that the own vehicle is going to collide with the oncoming vehicle and execute the collision avoiding control. 
     SUMMARY 
     The invention has been made for solving the problems described above. An object of the invention is to provide a vehicle control apparatus which can avoid unnecessary execution of the collision avoiding control when the own vehicle turn right or left in the traffic intersection. 
     According to the invention, a vehicle control apparatus comprises at least one sensor and an electronic control unit. The at least one sensor acquires object information on objects in a surrounding area around an own vehicle, including a forward area ahead of the own vehicle. The electronic control unit is configured to select at least one oncoming vehicle which is in the forward area and moves toward the own vehicle and set the selected at least one oncoming vehicle as a control target vehicle when the own vehicle turns right or left at a traffic intersection. Further, the electronic control unit is configured to acquire a first index value which represents a collision probability that the own vehicle collides with the control target vehicle. Furthermore, the electronic control unit is configured to execute a collision avoiding control of avoiding a collision of the own vehicle with the control target vehicle when the first index value satisfies a predetermined condition. 
     The electronic control unit is configured to calculate a second index value which represents a degree of turning of the own vehicle since the own vehicle starts turning right or left in the traffic intersection. Further, the electronic control unit is configured to move an area used to select the control target vehicle toward the own vehicle in an opposite direction to a turning direction of the own vehicle as the second index value increases. Furthermore, the electronic control unit is configured to select, as the control target vehicle, the oncoming vehicle which has been in the area for a predetermined time threshold or more. 
     The vehicle control apparatus according to the invention moves the area used to select the control target vehicle. Thereby, the vehicle control apparatus can select, as the control target vehicle, the oncoming vehicle which provably collides with the own vehicle. Thus, the vehicle control apparatus according to the invention can avoid selecting, as the control target vehicle, the oncoming vehicle in each of the situations (1) and (2) described above. 
     According to an aspect of the invention, the electronic control unit ( 10 ) may be configured to move a center position of the area from a first position to a second portion. In this aspect of the invention, the first position may be a position which is ahead of the own vehicle and remote from a longitudinal axis of the own vehicle in the turning direction of the own vehicle. Further, in this aspect of the invention, the second position may be a position which is ahead of the own vehicle and remote from the longitudinal axis of the own vehicle in an opposite direction to the turning direction of the own vehicle. 
     According to another aspect of the invention, the electronic control unit may be configured to decrease a size of the area as the second index value increases. 
     According to further another aspect of the invention, the electronic control unit may be configured to decrease a length of the area in a longitudinal direction of the own vehicle and a length of the area in a right-left direction of the own vehicle. 
     The vehicle control apparatus according to the aspects of the invention can avoid a situation that the oncoming vehicle at a position relatively far from the own vehicle is in the area. In addition, the vehicle control apparatus can avoid a situation that the oncoming vehicle turning in front of the own vehicle is in the area. Thereby, the unnecessary execution of the collision avoiding control can be avoided. 
     According to further another aspect of the invention, the electronic control unit may be configured to decrease the predetermined time threshold as a moving speed of the own vehicle increases. 
     The vehicle control apparatus configured according to this aspect of the invention can select the control target vehicle at an earlier timing and execute the collision avoiding control at a suitable timing when the moving speed of the own vehicle is high. 
     According to further another aspect of the invention, the vehicle control apparatus may comprise a storing section which stores road information. In this aspect, the electronic control unit may be configured to determine whether a particular lane condition that at least one turn-only lane is provided on a road on which the oncoming vehicle moves, is satisfied, based on the road information, and set the area such that the area does not cover the turn-only lane when the particular lane condition is satisfied. 
     The vehicle control apparatus configured according to this aspect of the invention can avoid the situation that the oncoming vehicle turning right or left in front of the own vehicle is in the area. 
     According to one or more embodiments, the electronic control unit may be realized by one or more micro-processors programmed to realize one or more functions described in this description. Further, according to one or more embodiments, the electronic control unit may be entirely or partially realized by hardware configured by integrated circuit such as ASIC dedicated to one or more applications. 
     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 general configuration view which shows a vehicle control apparatus according to a first embodiment of the invention. 
         FIG. 2  is a view which describes object information acquired by surrounding sensors. 
         FIG. 3  is a view which shows a situation that an own vehicle is turning right and there is an oncoming vehicle. 
         FIG. 4  is a view which describes a flow of processes of selecting the oncoming vehicle as a control target candidate vehicle. 
         FIG. 5  is a view which shows a positional relationship between the own vehicle and the oncoming vehicle at a point of time t 1 . 
         FIG. 6  is a view which shows the positional relationship between the own vehicle and the oncoming vehicle at a point of time t 2 . 
         FIG. 7  is a view which shows the positional relationship between the own vehicle and the oncoming vehicle at a point of time t 3 . 
         FIG. 8  is a view which shows change of a position of the oncoming vehicle on a two-dimension coordinate system. 
         FIG. 9  is a view which shows a situation that the oncoming vehicle passes a traffic intersection earlier than the own vehicle. 
         FIG. 10  is a view which shows a situation that the own vehicle passes the traffic intersection earlier than the oncoming vehicle. 
         FIG. 11  is a view which shows an area Sa used to select the control target vehicle. 
         FIG. 12  is a view which shows change of the area Sa on the two-dimension coordinate system according to the first embodiment. 
         FIG. 13  is a view which describes a flow of processes of selecting the oncoming vehicle as the control target vehicle. 
         FIG. 14  is a view which describes the flow of the processes of selecting the oncoming vehicle as the control target vehicle. 
         FIG. 15  is a view which describes the flow of the processes of selecting the oncoming vehicle as the control target vehicle. 
         FIG. 16  is a view which shows a situation that the oncoming vehicle passes the traffic intersection earlier than the own vehicle. 
         FIG. 17  is a view which shows a situation that the own vehicle passes the traffic intersection earlier than the oncoming vehicle. 
         FIG. 18  is a view which shows a flowchart of a first flag setting routine executed by a CPU of a collision avoiding ECU. 
         FIG. 19  is a view which shows a flowchart of a second flag setting routine executed by the CPU of the collision avoiding ECU. 
         FIG. 20  is a view which shows a flowchart of a collision avoiding control executing routine executed by the CPU of the collision avoiding ECU. 
         FIG. 21  is a view which shows change of the area Sa on the two-dimension coordinate system according to a second embodiment of the invention. 
         FIG. 22  is a view which shows a situation that the own vehicle is turning right, and there are two oncoming vehicles. 
         FIG. 23  is a view which describes a flow of processes of selecting the oncoming vehicle as the control target vehicle. 
         FIG. 24  is a view which describes the flow of the processes of selecting the oncoming vehicle as the control target vehicle. 
         FIG. 25  is a view which describes the flow of the processes of selecting the oncoming vehicle as the control target vehicle. 
         FIG. 26  is a view which describes processes of setting the area Sa according to a modified example of the embodiments of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Below, embodiments of the invention will be described with reference to the drawings. The drawings show specific embodiments but do not limit a technical scope of the invention. 
     First Embodiment 
     As shown in  FIG. 1 , a vehicle control apparatus according to a first embodiment (this vehicle control apparatus will be also referred to as “first apparatus”) is applied to a vehicle SV. The vehicle SV will be also referred to as “own vehicle SV” for distinguishing the own vehicle SV from other vehicles. 
     The first apparatus includes a collision avoiding ECU  10 , an engine ECU  20 , a brake ECU  30 , a meter ECU  40 , and a navigation ECU  50 . Some or all of the ECUs  10 ,  20 ,  30 ,  40 , and  50  may be integrated into one ECU. Hereinafter, the collision avoiding ECU  10  will be referred to as “PCS ECU  10 ”. 
     Each of the ECUs  10 ,  20 ,  30 ,  40 , and  50  is an electronic control unit which includes a micro-computer as a main component. The ECUs  10 ,  20 ,  30 ,  40 , and  50  are electrically connected to send and receive information to and from each other via a CAN (Controller Area Network) not shown. 
     The micro-computer includes a CPU, a ROM, a RAM, a non-volatile memory, and an interface I/F. For example, the PCS ECU  10  includes a micro-computer which includes a CPU  101 , a ROM  102 , a RAM  103 , a non-volatile memory  104 , and an interface (I/F)  105 . The CPU  101  is configured or programmed to realize various functions by executing instructions, or programs, or routines stored in the ROM  102 . 
     The PCS ECU  10  is electrically connected to sensors described below. The PCS ECU  10  is configured or programmed to receive detection signals or output signals. Each sensor may be electrically connected to one of the ECUs  20 ,  30 ,  40 , and  50  other than the PCS ECU  10 . In this case, the PCS ECU  10  receives the detection signals or the output signals of the sensors from the ECU to which the sensor is electrically connected via the CAN. 
     A vehicle moving speed sensor  11  detects a moving speed Vs of the own vehicle SV and outputs signals which represent the moving speed Vs. A steering angle sensor  12  detects a steering angle θ of the own vehicle SV and outputs signals which represent the steering angle θ. A yaw rate sensor  13  detects a yaw rate Yr of the own vehicle SV and outputs signals which represent the yaw rate Yr. 
     Acceleration sensors  14  include a first acceleration sensor  14   a  and a second acceleration sensor  14   b . The first acceleration sensor  14   a  detects a first acceleration ax which is an acceleration or a longitudinal acceleration in a longitudinal direction of the own vehicle SV. The first acceleration sensor  14   a  outputs signals which represent the first acceleration ax. The second acceleration sensor  14   b  detects a second acceleration ay which is an acceleration or a lateral acceleration in a lateral direction of the own vehicle SV. The second acceleration sensor  14   b  outputs signals which represent the second acceleration ay. 
     It should be noted that the steering angle θ, the yaw rate Yr, and the second acceleration ay are zero, respectively when the own vehicle SV moves straight. The steering angle θ, the yaw rate Yr, and the second acceleration ay take positive values when the own vehicle SV turns left. On the other hand, the steering angle θ, the yaw rate Yr, and the second acceleration ay take negative values when the own vehicle SV turns right. 
     Hereinafter, information which represents a moving state of the own vehicle SV output from the sensors  11  to  14 , will be also referred to as “moving state information”. 
     Surrounding sensors  15  are configured to acquire information on standing objects in a surrounding area around the own vehicle SV. The surrounding area around the own vehicle SV includes at least a forward area ahead of the own vehicle SV. In this embodiment, the surrounding area around the own vehicle SV includes the forward area ahead of the own vehicle SV, a right side area of the own vehicle SV, and a left side area of the own vehicle SV. The standing objects include, for example, (i) moving objects such as four-wheel vehicles, two-wheel vehicles, and pedestrians and (ii) non-moving objects such as power poles, trees, and guard rails. Hereinafter, the standing objects will be simply referred to as “objects”. The surrounding sensors  15  calculate and output information on the objects (hereinafter, the information on the objects will be referred to as “object information”). 
     As shown in  FIG. 2 , the surrounding sensors  15  acquire the object information, using a two dimension coordinate system. The two dimension coordinate system is defined by an x-axis and a y-axis. An origin of the x-axis and the y-axis is a center position O of a front portion of the own vehicle SV in a width direction of the own vehicle SV. The x-axis is a coordinate axis which extends in a longitudinal direction of the own vehicle SV and passes through the center position O of the front portion of the own vehicle SV. Positions ahead of the own vehicle SV are represented by positive values along the x-axis. The y-axis is a coordinate axis which extends perpendicular to the x-axis. Positions at the right side of the own vehicle SV are represented by positive values along the y-axis. 
     The object information on the object (n) includes information on longitudinal distances Dfx(n) of the objects (n), lateral positions Dfy(n) of the objects (n), orientations θp(n) of the objects (n), moving directions of the objects (n), relative speeds Vfx(n) of the objects (n), and types of the objects (n). 
     The longitudinal distance Dfx(n) is a distance in an x-axis direction between the object (n) and the origin O. The longitudinal distance Dfx(n) takes positive and negative values. The lateral distance Dfy(n) is a distance in a y-axis direction between the object (n) and the origin O. The lateral distance Dfy(n) takes positive and negative values. The relative speed Vfx(n) is a moving speed of the object (n) with respect to the own vehicle SV in the x-axis direction. In other words, the relative speed Vfx(n) is a difference between a moving speed Vn of the object (n) in the x-axis direction and the moving speed Vs of the own vehicle SV in the x-axis direction (Vfx(n)=Vn−Vs). The orientation Op(n) is an angle defined by the x-axis and a line which connects the origin O and the object (n). The moving direction of the object (n) is a relative moving direction with respect to the own vehicle SV. The type of the object (n) corresponds to information on which the object is, the moving object or the non-moving object. In this embodiment, when the object is the moving-object, the type of the object (n) includes information on which the object is, the four-wheel vehicle, the two-wheel vehicle, or the pedestrian. 
     Again, referring to  FIG. 1 , the surrounding sensors  15  include at least one radar sensor  16 , at least one camera sensor  17 , and an object detecting ECU  18 . 
     The radar sensor  16  includes a radar wave transmitting/receiving section and an information processing section. The radar wave transmitting/receiving section transmits electromagnetic waves such as radio waves of a millimeter wave band (hereinafter, the radio waves of the millimeter wave band will be referred to as “millimeter waves”). In addition, the radar wave transmitting/receiving section receives the millimeter waves which are reflected by the objects in a transmitting area. That is, the radar wave transmitting/receiving section receives reflected waves. The information processing section detects the object (n), based on reflected wave information on (i) a phase difference between the transmitted millimeter wave and the received reflected wave, (ii) an attenuated level of the reflected wave, and (iii) time taken to receive the reflected wave from transmitting the millimeter wave. In addition, the information processing section acquires or calculates the object information on the object (n), based on the reflected wave information. 
     The camera sensor  17  includes a camera and an image processing section. The camera outputs image data to the image processing section with a predetermined frame rate. The image processing section detects the objects (n) and acquires or calculates the object information on the detected objects (n), based on the image data. In addition, the image processing section recognizes or determines the types of the detected objects (n). The image processing section has stored patten data of the objects such as the four-wheel vehicles, the two-wheel vehicles, and the pedestrians in a memory (for example, the ROM). The image processing section recognizes which each object (n) is, the four-wheel vehicle, the two-wheel vehicle, or the pedestrian by pattern-matching the image data. 
     The image processing section may be configured to detect lane markings, based on the image data. The lane markings define lanes. The lane markings include (i) lane markings which define a lane in which the own vehicle SV is moving and (ii) lane markings which define oncoming lanes. Further, the image processing section may be configured to acquire or calculate positions of the lane markings as lane information. 
     The object detecting ECU  18  determines conclusive object information by synthesizing the object information acquired by the radar sensor  16  and the object information acquired by the camera sensor  17 . The object detecting ECU  18  outputs the object information and the lane information to the PCS ECU  10  as vehicle surrounding information. 
     The engine ECU  20  is electrically connected to engine actuators  21 . The engine actuators  21  include a throttle valve actuator which changes an opening degree of a throttle valve of a spark-ignition gasoline injection type of an internal combustion engine  22 . The engine ECU  20  can change torque which the internal combustion engine  22  generates by driving the engine actuators  21 . The torque generated by the internal combustion engine  22  is transmitted to driven-wheels (not shown) of the own vehicle SV via a transmission (not shown). Thus, the engine ECU  20  can control driving force and change an accelerated state of the own vehicle SV or an acceleration of the own vehicle SV by controlling the engine actuators  21 . 
     When the own vehicle SV is a hybrid vehicle, the engine ECU  20  can control the driving force generated by one or both of the internal combustion engine and at least one electric motor as vehicle driving sources. When the own vehicle SV is an electric vehicle, the engine ECU  20  can control the driving force generated by at least one electric motor as the vehicle driving source. 
     The brake ECU  30  is electrically connected to brake actuators  31 . The brake actuators  31  include hydraulic circuits. The hydraulic circuits include flow passages through which braking liquid flows, valves, at least one pump, and at least one motor which drives the at least one pump. The brake ECU  30  adjusts hydraulic pressure applied to wheel cylinders incorporated in brake mechanisms  32  by controlling the brake actuators  31 . The hydraulic pressure causes the wheel cylinders to generate friction braking force applied to wheels of the own vehicle SV. Thus, the brake ECU  30  can control the braking force and change the accelerated state of the own vehicle SV or deceleration or negative acceleration of the own vehicle SV by controlling the brake actuators  31 . 
     The meter ECU  40  is electrically connected to a display  41 , a speaker  42 , and a turn signal switch  43 . The display  41  is a multi-information display provided in front of a driver&#39;s seat. The display  41  may be a head-up display. The meter ECU  40  displays an alerting mark (for example, warning lamp) on the display  41  in response to a command from the PCS ECU  10 . In addition, the meter ECU  40  outputs alerting sound for alerting a driver of the own vehicle SV from the speaker  42  in response to the command from the PCS ECU  10 . Further, the meter ECU  40  blinks left and right turn signal lamps (not shown) in response to a signal from the turn signal switch  43 . The meter ECU  40  sends an activated state of the left or right turn signal lamps to the PCS ECU  10 . 
     The navigation ECU  50  is electrically connected to a GPS receiver  51 , a map storing section  52 , and a touch panel  53 . The GPS receiver  51  receives GPS signals used to detect a longitude and a latitude of a place where the own vehicle SV is located. The map storing section  52  stores map information. The map information includes road information. The road information includes information on positions of lanes, the number of the lanes, lengths of the lanes in a width direction of a road (i.e., widths of the lanes), and types of the lanes (for example, a right-turn-only lane or a left-turn-only lane). The navigation ECU  50  performs various calculation processing, based on (i) the longitude and the latitude of the place where the own vehicle SV is located and (ii) the map information and displays a position of the own vehicle SV on a map on the touch panel  53 . 
     &lt;Summary of Collision Avoiding Control&gt; 
     When the PCS ECU  10  is configured to determine that a predetermined PCS execution condition is satisfied, based on a method described later, the PCS ECU  10  executes the known collision avoiding control. The collision avoiding control of this embodiment is a control of (i) avoiding collision of the own vehicle SV with oncoming vehicles when the own vehicle SV is turning right or (ii) reducing damage derived from the collision of the own vehicle SV with the oncoming vehicles when the own vehicle SV is turning right. Hereinafter, this collision avoiding control will be referred to “PCS control”. 
     In particular, the PCS ECU  10  determines whether the own vehicle SV starts turning right, based on the activated state of the right turn signal lamps and/or the moving state information such as the steering angle θ and the yaw rate Yr. For example, when the right turn signal lamps are turned on, and the yaw rate Yr is smaller than a predetermined right-turn start threshold (a negative value) Yrth, the PCS ECU  10  determines that the own vehicle SV starts turning right. 
     Next, the PCS ECU  10  recognizes the objects in the surrounding area around the own vehicle SV, based on the object information included in the vehicle surrounding information. 
     Then, the PCS ECU  10  selects or picks up the oncoming vehicles which are in the forward area ahead of the own vehicle SV and are moving toward the own vehicle SV from among the recognized objects. In this embodiment, the oncoming vehicles include the four-wheel vehicles or the two-wheel vehicles. The selected oncoming vehicles are candidates of the oncoming vehicles which are a target vehicles of the PCS control. Hereinafter, the selected oncoming vehicles will be referred to as “control target candidate vehicles”. Further, the oncoming vehicles which are the target vehicles of the PCS control will be referred to as “control target vehicles”. Below, processes of selecting the control target candidate vehicles will be described 
     In an example shown in  FIG. 3 , the own vehicle SV moves in a first traffic lane Ln 1 . The own vehicle SV is turning right in a traffic intersection Is 1 . Further, a first other vehicle OV 1  moves in a first oncoming lane Lo 1 . The first oncoming lane Lo 1  is an oncoming lane for the first moving lane Ln 1 . 
     The PCS ECU  10  recognizes the first other vehicle OV 1 , based on the object information. Then, as shown in  FIG. 4 , the PCS ECU  10  draws the own vehicle SV and the first other vehicle OV 1  in a simplified manner on the two dimension coordinate system. In particular, the PCS ECU  10  draws a first rectangle  400  on the two dimension coordinate system. The first rectangle  400  represents a body of the own vehicle SV. The ROM  102  has stored information on a size of the body of the own vehicle SV. The PCS ECU  10  sets a size of the first rectangle  400 , based on this stored information on the size of the body of the own vehicle V. In addition, the PCS ECU  10  draws a second rectangle  410  on the two dimension coordinate system. The second rectangle  410  represents a body of the first other vehicle OV 1 . A size of the second rectangle  410  may be set, based on a size of a body of a general vehicle. 
     The PCS ECU  10  specifies an apex  401  nearest the second rectangle  410  among apexes of the first rectangle  400 . Hereinafter, the apex  401  will be referred to as “first apex  401 ”. The first apex  401  corresponds to a right corner portion of the front portion of the own vehicle SV. In addition, the PCS ECU  10  specifies an apex  411  nearest the first rectangle  400  among apexes of the second rectangle  410 . Hereinafter, the apex  411  will be referred to as “second apex  411 ”. The second apex  411  corresponds to a right corner portion of a front portion of the first other vehicle OV 1 . 
     The PCS ECU  10  draws a first predicted route tr 1  on the two dimension coordinate system, based on the moving state information. The first predicted route tr 1  is a route which the first apex  401  passes during a period from the current point of time (a first pint of time) to a second point of time assuming that the own vehicle SV moves with maintaining the current moving state such as the moving speed Vs and the yaw rate Yr. The second point of time is a time after the current point of time by a predetermined time ta. 
     The PCS ECU  10  calculates (i) a moving direction of the first other vehicle OV 1  and (ii) a moving speed Vol of the first other vehicle OV 1 , based on the object information. Then, the PCS ECU  10  draws a second predicted route tr 2  on the two dimension coordinate system, based on (i) the moving direction of the first other vehicle OV 1  and (ii) the moving speed Vol of the first other vehicle OV 1 . The second predicted route tr 2  is a route which the second apex  411  passes during the period from the current point of time (the first point of time) to the second point of time assuming that the first other vehicle OV 1  moves with maintaining the current moving state such as the moving direction and the moving speed Vol. 
     The PCS ECU  10  determines whether the first predicted route tr 1  and the second predicted route tr 2  cross each other. When the first predicted route tr 1  and the second predicted route tr 2  cross each other, the own vehicle SV has a probability of colliding with the first other vehicle OV 1 . In this case, the PCS ECU  10  selects the first other vehicle OV 1  as the control target candidate vehicle. 
     Then, the PCS ECU  10  selects or sets the control target candidate vehicle as the control target vehicle when the control target candidate vehicle in question satisfies a predetermined condition described below (hereinafter, this predetermined condition will be referred as “control target condition”). 
     When the PCS ECU  10  selects the control target candidate vehicle or the first other vehicle OV 1  as the control target vehicle, the PCS ECU  10  determines whether the predetermined PCS execution condition is satisfied. The predetermined PCS execution condition is a condition used to determine whether to execute or start an execution of the PCS control. 
     The predetermined PCS execution condition is a condition which relates to a first index value. The first index value represents collision probability that the own vehicle SV collides with the control target vehicle. In this embodiment, the first index value is time Tc which will be taken for the own vehicle SV to reach a moving path of the first other vehicle OV 1  or the second predicted route tr 2 . It should be noted that the time Tc is a margin time until the own vehicle SV collides with the first other vehicle OV 1 . Hereinafter, the time Tc will be referred to as “first index value Tc”. 
     In particular, as show in  FIG. 4 , the PCS ECU  10  acquires a crossing position Ps at which the first predicted route tr 1  and the second predicted route tr 2  cross each other. Then, the PCS ECU  10  acquires time which is predictively taken for the first apex  401  to reach the crossing position Ps as the first index value Tc, based on the moving state information such as the moving speed Vs and the yaw rate Yr. 
     When the first index value Tc becomes equal to or smaller than a predetermined first time threshold Tcth, the PCS ECU  10  determines that the predetermined PCS execution condition becomes satisfied and executes the PCS control. 
     The PCS control includes (i) a driving force limiting control of limiting the driving force applied to the own vehicle SV, (ii) a braking force control of applying the braking force to the wheels of the own vehicle SV, and (iii) an alerting control of alerting the driver of the own vehicle SV. In particular, the PCS ECU  10  sends driving command signals to the engine ECU  20 . When the engine ECU  20  receives the driving command signals from the PCS ECU  10 , the engine ECU  20  controls the engine actuators  21  to limit the driving force such that the actual acceleration of the own vehicle SV corresponds to a target acceleration AG (for example, zero) represented by the driving command signals. In addition, the PCS ECU  10  sends braking command signals to the brake ECU  30 . When the brake ECU  30  receives the braking command signals from the PCS ECU  10 , the brake ECU  30  controls the brake actuators  31  to apply the braking force to the wheels of the own vehicle SV such that the actual acceleration of the own vehicle SV corresponds to a target deceleration TG represented by the braking command signals. In addition, the PCS ECU  10  sends alerting command signals to the meter ECU  40 . When the meter ECU  40  receives the alerting command signals from the PCS ECU  10 , the meter ECU  40  displays the alerting mark on the display  41  and outputs the alerting sound from the speaker  42 . 
     SUMMARY OF OPERATIONS 
     As described above, the known apparatus may execute the PCS control in the situations (1) and (2) described above. That is, the known apparatus may execute the PCS control in a situation that the PCS control should not be executed. In order to solve this problem, the PCS ECU  10  of this embodiment selects the control target vehicles, using change of a positional relationship between the own vehicle SV and the first other vehicle OV 1 . 
       FIG. 5  shows the same situation as the situation shown in  FIG. 4 . Thus,  FIG. 5  shows a positional relationship between (i) the first rectangle  400  or the own vehicle SV and (ii) the second rectangle  410  or the first other vehicle OV 1  at a point of time t 1 . Below, a description “(xi, yi)” represents an x-y-coordinate of a center position Pi of the second rectangle  410  on the two dimension coordinate system. The center position Pi is a center position of the front portion of the first other vehicle OV 1  in a width direction of the first other vehicle OV 1 . Hereinafter, the center position Pi of the second rectangle  410  will be referred to as “position Pi of the first other vehicle OV 1 ”. 
     At the point of time t 1 , the own vehicle SV starts turning right. At the point of time t 1 , a distance in the longitudinal direction of the own vehicle SV between the own vehicle SV and the first other vehicle OV 1  is long. That is, the longitudinal distance Dfx is long. Thus, a value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  on the two dimension coordinate system is a relatively great positive value. In addition, the first other vehicle OV 1  is at the right side of a longitudinal axis of the own vehicle SV. That is, the first other vehicle OV 1  is at the right side of the x-axis. Thus, a value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  on the two dimension coordinate system is a positive value. 
       FIG. 6  shows a positional relationship between the own vehicle SV and the first other vehicle OV 1  at a point of time t 2  after the point of time t 1 . The own vehicle SV has entered in the traffic intersection Is 1 . The first other vehicle OV 1  has approached the traffic intersection Is 1  since the point of time t 1 . 
     A degree of right turning of the own vehicle SV or a degree that the own vehicle SV turns right at the point of time t 2  is greater than the degree of right turning of the own vehicle SV at the point of time t 1 . The longitudinal distance Dfx between the own vehicle SV and the first other vehicle OV 1  at the point of time t 2  is shorter than the longitudinal distance Dfx between the own vehicle SV and the first other vehicle OV 1  at the point of time t 1 . Thus, the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  at the point of time t 2  is smaller than the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  at the point of time t 1 . Also, the value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  at the point of time t 2  is smaller than the value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  at the point of time t 1 . 
       FIG. 7  shows the positional relationship between the own vehicle SV and the first other vehicle OV 1  at a point of time t 3  after the point of time t 2 . At the point of time t 3 , the own vehicle SV is entering in the first oncoming lane Lo 1 . On the other hand, the first other vehicle OV 1  has entered in the traffic intersection Is 1 . 
     The degree of right turning of the own vehicle SV at the point of time t 3  is greater than the degree of right turning of the own vehicle SV at the point of time t 2 . The longitudinal distance Dfx between the own vehicle SV and the first other vehicle OV 1  at the point of time t 3  is shorter than the longitudinal distance Dfx between the own vehicle SV and the first other vehicle OV 1  at the point of time t 2 . Thus, the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  at the point of time t 3  is smaller than the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  at the point of time t 2 . Also, the value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  at the point of time t 3  is smaller than the value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  at the point of time t 2 . Thus, at the point of time t 3 , the own vehicle SV has approached the first other vehicle OV 1 . Thus, the own vehicle SV has the high probability of finally colliding with the first other vehicle OV 1 . 
       FIG. 8  shows the positions Pi of the first other vehicle OV 1  at the point of time t 1 , the point of time t 2 , and the point of time t 3 . As can be understood from  FIG. 8 , when the positional relationship between the own vehicle SV and the first other vehicle OV 1  on the two dimension coordinate system changes as described below, the own vehicle SV has the high probability of finally colliding with the first other vehicle OV 1 . 
     As time elapses from the point of time t 1  when the own vehicle SV starts turning right, the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  decreases, and the value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  also decreases. In other words, as the degree of right turning of the own vehicle SV increases since the point of time t 1 , the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  decreases, and the value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  also decreases. 
     In particular, when changes of the values described below are detected, the own vehicle SV has the high probability of finally colliding with the first other vehicle OV 1 . 
     (A) The value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  is a relatively great positive value at the point of time t 1  when the degree of right turning of the own vehicle SV is small. In addition, the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  is a relatively small positive value at the point of time t 3  when the degree of right turning of the own vehicle SV is great. 
     (B) The value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  is a positive value at the point of time t 1  when the degree of right turning of the own vehicle SV is small. In addition, the value of the y-coordinate yi of the position Pi of the first other vehicle OV 1  is a negative value at the point of time t 3  when the degree of right turning of the own vehicle SV is great. 
     On the other hand, in the situation (1) described above, as shown in  FIG. 9 , the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  is a negative value at a point of time when the degree of right turning of the own vehicle SV is relatively small. In addition, in the situation (2) described above, as shown in  FIG. 10 , the values of the x-coordinate xi and the y-coordinate yi of the position Pi of the first other vehicle OV 1  are negative values at a point of time when the degree of right turning of the own vehicle SV is great. 
     In consideration of the situations described above, the PCS ECU  10  sets an area Sa on the two dimension coordinate system. The area Sa is used to select the control target vehicles. 
     The area Sa of this embodiment is a rectangular area ahead of the own vehicle SV. That is, the area Sa of this embodiment is a rectangular area in an area that the value of the x-coordinate is positive. Long sides and short sides of the area Sa are parallel to the x-axis and the y-axis, respectively. As shown in  FIG. 11 , the area Sa is defined by four vertexes v 1  to v 4 . 
     An x-coordinate value of the vertex v 1  is a smallest one of the four vertexes v 1  to v 4  of the area Sa. A y-coordinate value of the vertex v 1  is a smallest one of the four vertexes v 1  to v 4  of the area Sa. 
     The x-coordinate value of the vertex v 2  is a greatest one of the four vertexes v 1  to v 4  of the area Sa. The y-coordinate value of the vertex v 2  is the same as the y-coordinate value of the vertex v 1 . 
     The x-coordinate value of the vertex v 3  is the same as the x-coordinate value of the vertex v 2 . The y-coordinate value of the vertex v 3  is a greatest one of the four vertexes v 1  to v 4  of the area Sa. 
     The x-coordinate value of the vertex v 4  is the same as the x-coordinate value of the vertex v 1 . The y-coordinate value of the vertex v 4  is the same as the y-coordinate value of the vertex v 3 . 
     Hereinafter, a side between the vertex v 1  and the vertex v 2  will be referred to as “first side sd 1 ”, a side between the vertex v 2  and the vertex v 3  will be referred to as “second side sd 2 ”, a side between the vertex v 3  and the vertex v 4  will be referred to as “third side sd 3 ”, and a side between the vertex v 4  and the vertex v 1  will be referred to as “fourth side sd 4 ”. 
     A length Lx of the area Sa in the x-axis direction or the longitudinal direction of the own vehicle SV is a predetermined first length L 1 . A length Ly of the area Sa in the y-axis direction or the right-left direction of the own vehicle SV is a predetermined second length L 2 . In this embodiment, the predetermined first length L 1  is longer than the predetermined second length L 2 . 
     As described above, when the right turn signal lamp is turned on, and the yaw rate Yr is smaller than a right-turn start threshold Yrth, the PCS ECU  10  determines that the own vehicle SV starts turning right. A point of time when the PCS ECU  10  determines that the own vehicle SV starts turning right is a point of time when the own vehicle SV starts turning right. Thus, hereinafter, the point of time when the PCS ECU  10  determines that the own vehicle SV starts turning right will be referred to as “turning start point of time”. The PCS ECU  10  calculates a second index value. The second index value represents the degree of turning of the own vehicle SV since the turning start point of time. That is, the second index value represents a moving degree of the own vehicle SV since the turning start point of time. In this embodiment, the second index value is a time integration value dgt of an absolute value of the yaw rate Yr since the turning start point of time. Hereinafter, the time integration value dgt will be referred to as “second index value dgt”. Thus, as the degree of turning of the own vehicle SV increases, the second index value dgt increases. 
     As shown in  FIG. 12 , the PCS ECU  10  moves the area Sa on the two dimension coordinate system, based on the second index value dgt. In particular, the PCS ECU  10  moves the area Sa in a negative direction of the x-axis and in a negative direction of the y-axis as the second index value dgt increases. That is, as the second index value dgt increases, the PCS ECU  10  moves the area Sa toward the own vehicle SV in an opposite direction to a turning direction of the own vehicle SV or the right direction. Thereby, a position of the second side sd 2  and a position of the fourth side sd 4  gradually approach the own vehicle SV or move in a negative direction of the x-axis, and a position of the first side ad 1  and a position of the third side sd 3  gradually move in the opposite direction to the turning direction of the own vehicle SV or a negative direction of the y-axis. It should be noted that the PCS ECU  10  moves the area Sa within an area that the value of the x-coordinate is positive. That is, the PCS ECU  10  moves the area Sa within an area above the y-axis. 
     In particular, at the turning start point of time, the x-coordinate values of the vertexes v 1  to v 4  of the area Sa are positive, and the y-coordinate values of the vertexes v 1  to v 4  of the area Sa are positive. Thus, at the turning start point of time, a center position Cp of the area Sa is set at a position which is ahead of the own vehicle SV and remote from the longitudinal axis of the own vehicle SV or the x-axis in the turning direction or the right direction. It should be noted that the center position Cp of the area Sa is a geometric gravity center of the area Sa. 
     As the second index value dgt increases, the x-coordinate values of the vertexes v 1  to v 4  gradually increase, and the y-coordinate values of the vertexes v 1  to v 4  gradually decrease (see an area Sa′ and an area Sa″). 
     When the second index value dgt becomes greater than a predetermined value, the y-coordinate values of the vertex viand the vertex v 2  become negative (for example, see the area Sa′). Finally, the x-coordinate value of the center position Cp of the area Sa is positive, and the y-coordinate value of the center position Cp of the area Sa is negative (see the area Sa″). Thereby, the center position Cp of the area Sa is finally set at a position which is ahead of the own vehicle SV and remote from the longitudinal axis of the own vehicle SV or the x-axis in the opposite direction to the turning direction or the left direction. 
     As described above, the PCS ECU  10  moves the center position Cp of the area Sa from a first position to a second position. In this regard, the first position corresponds to the center position Cp of the area Sa and is a position which is ahead of the own vehicle SV and remote from the longitudinal axis of the own vehicle SV in the turning direction or the right direction. Further, the second position corresponds to the center position Cp of the area Sa″ and is a position which is ahead of the own vehicle SV and remote from the longitudinal axis of the own vehicle SV in the opposite direction to the turning direction or the left direction. 
     A fact that the first other vehicle OV 1  continues to be in the area Sa moved as described above means that the own vehicle SV has a high probability of colliding with the first other vehicle OV 1 . Thus, in this embodiment, the control target condition is a condition that the position Pi of the control target candidate vehicle (the first other vehicle OV 1 ) continues to be in the area Sa for a predetermined second time threshold Tmth or more. The PCS ECU  10  selects or sets, as the control target vehicle, the control target candidate vehicle which satisfies the control target condition described above. 
     Operation Examples 
     Processes of selecting the control target vehicles will be described with reference to  FIG. 13  to  FIG. 15 .  FIG. 13  to  FIG. 15  show the same situations as the situations shown in  FIG. 5  to  FIG. 7 , respectively. 
     &lt;Point of Time t 1 &gt; 
     As shown in  FIG. 13 , at the point of time t 1 , the right turn signal lamps are turned on, and the yaw rate Yr is smaller than the predetermined right-turn start threshold Yrth. Thus, the PCS ECU  10  determines that the own vehicle SV starts turning right. Then, the PCS ECU  10  selects the first other vehicle OV 1  as the control target candidate vehicle. Then, the PCS ECU  10  calculates the second index value dgt. Then, the PCS ECU  10  acquires the x-coordinate values and the y-coordinate values of four vertexes v 1  to v 4  which define the area Sa by applying the second index value dgt to a map MP(dgt). The map MP(dgt) defines a relationship between the second index value dgt and the x-coordinate and y-coordinate values of the four vertexes v 1  to v 4 . Then, the PCS ECU  10  sets the area Sa ahead of the own vehicle SV. This area Sa corresponds to the area Sa shown in  FIG. 12 . The PCS ECU  10  determines that the position Pi of the first other vehicle OV 1  is in the area Sa. 
     &lt;Point of Time t 2 &gt; 
     As shown in  FIG. 14 , at the point of time t 2 , the PCS ECU  10  calculates the second index value dgt. Then, as described above, the PCS ECU  10  sets the area Sa ahead of the own vehicle SV by applying the second index value dgt to the map MP(dgt). This area Sa corresponds to the area Sa′ shown in  FIG. 12 . The PCS ECU  10  determines that the position Pi of the first other vehicle OV 1  is in the area Sa. 
     &lt;Point of Time t 3 &gt; 
     As shown in  FIG. 15 , at the point of time t 3 , the PCS ECU  10  calculates the second index value dgt. Then, as described above, the PCS ECU  10  sets the area Sa ahead of the own vehicle SV by applying the second index value dgt to the map MP(dgt). This area Sa corresponds to the area Sa″ shown in  FIG. 12 . The PCS ECU  10  determines that the position Pi of the first other vehicle OV 1  is in the area Sa. At the point of time t 3 , the predetermined second time threshold Tmth elapses since the point of time t 1 . Thus, the position Pi of the first other vehicle OV 1  continues to be in the area Sa for the predetermined second time threshold Tmth or more. Thus, the PCS ECU  10  determines that the first other vehicle OV 1  satisfies the control target condition. Then, the PCS ECU  10  selects, as the control target vehicle, the first other vehicle OV 1  which is the control target candidate vehicle. 
     When the PCS execution condition becomes satisfied after the point of time t 3 , that is, the first index value Tc becomes equal to or smaller than the predetermined first time threshold Tcth, the PCS ECU  10  executes the PCS control. Thereby, the PCS ECU  10  can select, as the control target vehicle, the first other vehicle OV 1  which has a high probability of colliding with the own vehicle SV. 
     On the other hand, in the situation (1) described above, as shown in  FIG. 16 , the position Pi of the first other vehicle OV 1  is outside of the area Sa after a certain point of time. That is, the position Pi of the first other vehicle OV 1  may not continue to be in the area Sa for the predetermined second time threshold Tmth or more. 
     Also, in the situation (2) described above, as shown in  FIG. 17 , the position Pi of the first other vehicle OV 1  is outside of the area Sa after a certain point of time. That is, the position Pi of the first other vehicle OV 1  may not continue to be in the area Sa for the predetermined second time threshold Tmth or more. Thus, in the situations (1) and (2), the control target condition is unlikely to become satisfied. In this case, the PCS ECU  10  does not select the first other vehicle OV 1  as the control target vehicle. Thus, the PCS control can be prevented from being executed in the situation that the PCS control should not be executed. 
     &lt;Operations&gt; 
     As described above, the CPU  101  of the PCS ECU  10  (hereinafter, the CPU  101  will be simply referred to as “CPU”) determines, based on (i) the activated state of the right turn signal lamps and (ii) the moving state information, whether the own vehicle SV starts turning right. The CPU executes routines shown in  FIG. 18  to  FIG. 20  each time a predetermined time dT elapses after the CPU determines that the own vehicle SV starts turning right. 
     Each time the predetermined time dT elapses, the CPU acquires the moving state information from the sensors  11  to  14 , acquires the vehicle surrounding information from the surrounding sensors  15 , and stores the acquired information in the RAM  103 . 
     It should be noted that the CPU sets values of various flags (i.e., a first flag X 1  and a second flag X 2  described later) to “0” and sets a variable (i.e., a duration time variable Tm described later) to zero in an initializing routine. The initializing routine is executed when an ignition switch (not shown) is operated from an OFF state to an ON state. 
     At a predetermined timing, the CPU starts a process from a step  1800  of the routine shown in  FIG. 18  and proceeds with the process to a step  1801  to determine, based on the object information, whether there are one or more objects in the surrounding area around the own vehicle SV. When there is no object in the surrounding area around the own vehicle SV, the CPU determines “No” at the step  1801  and proceeds with the process directly to a step  1895  to terminate the process of this routine once. 
     On the other hand, when there are one or more objects in the surrounding area around the own vehicle SV, the CPU determines “Yes” at the step  1801  and proceeds with the process to a step  1802 . As the step  1802 , the CPU determines whether there is one or more control target candidate vehicles among the objects recognized at the step  1801 . In particular, as shown in  FIG. 4 , the CPU calculates the first predicted route tr 1  of the own vehicle SV and the second predicted routes tr 2  of the objects recognized at the step  1801 . The CPU selects, as the control target candidate vehicles, the objects having the second predicted routes tr 2  which cross the first predicted route tr 1 . In this case, the CPU determines “Yes” at the step  1802  and proceeds with the process to a step  1803  to sets the value of a first flag X 1  to “1”. When the value of the first flag X 1  is “0”, the first flag X 1  represents that there is no control target candidate vehicle. On the other hand, when the value of the first flag X 1  is “1”, the first flag X 1  represents that there is at least one control target candidate vehicle. Then, the CPU proceeds with the process to the step  1895  to terminate the process of this routine once. 
     It should be noted that when there is no control target candidate vehicle, the CPU determines “No” at the step  1802  and proceeds with the process directly to the step  1895  to terminate the process of this routine once. 
     Further, at a predetermined timing, the CPU executes the routine shown in  FIG. 19 . It should be noted that when the CPU determines that there are the control target candidate vehicles in the routine shown in  FIG. 18 , the CPU executes the routine shown in  FIG. 19  for each control target candidate vehicle. 
     The CPU starts a process from a step  1900  of the routine shown in  FIG. 19  and proceeds with the process to a step  1901  to determine whether the value of the first flag X 1  is “1”. When the value of the first flag X 1  is not “1”, the CPU determines “No” at the step  1901  and proceeds with the process directly to a step  1995  to terminate the process of this routine once. 
     When there is at least one control target candidate vehicle, and the value of the first flag X 1  is “1”, the CPU determines “Yes” at the step  1901  and sequentially executes processes of steps  1902  and  1903  described below. Then, the CPU proceeds with the process to a step  1904 . 
     Step  1902 : The CPU calculates the second index value dgt as described above. 
     Step  1903 : The CPU acquires the x-coordinates and y-coordinates of the four vertexes v 1  to v 4  which define the area Sa by applying the second index value dgt to the map MP(dgt). Then, the CPU sets the area Sa ahead of the own vehicle SV. 
     Then, at a step  1904 , the CPU acquires the position Pi of the control target candidate vehicle or the oncoming vehicle. Then, the CPU determines whether the position Pi of the control target candidate vehicle is in the area Sa. When the position Pi of the control target candidate is not in the area Sa, the CPU determines “No” at the step  1904  and proceeds with the process to a step  1908  to set the duration time variable Tm to zero. The time variable Tm represents the duration time that the position Pi of the control target candidate vehicle continues to be in the area Sa. 
     On the other hand, when the position Pi of the control target candidate vehicle is in the area Sa, the CPU determines “Yes” at the step  1904  and proceeds with the process to a step  1905  to increase the time variable Tm by the predetermined time dT. As described above, the predetermined time dT corresponds to a cycle of executing the routine shown in  FIG. 9 . 
     Then, at a step  1906 , the CPU determines whether the time variable Tm is greater than or equal to the predetermined second time threshold Tmth. When the time variable Tm is not greater than or equal to the predetermined second time threshold Tmth, the CPU determines “No” at the step  1906  and proceeds with the process directly to the step  1995  to terminate the process of this routine once. 
     On the other hand, when the time variable Tm is greater than or equal to the predetermined second time threshold Tmth, the CPU determines “Yes” at the step  1906  and proceeds with the process to a step  1907  to set the value of the second flag X 2  to “1”. When the value of the second flag X 2  is “0”, the second flag X 2  represents that there is no control target vehicle. On the other hand, when the value of the second flag X 2  is “1”, the second flag X 2  represents that there is at least one control target vehicle. Then, the CPU proceeds with the process to the step  1995  to terminate the process of this routine once. 
     Further, at a predetermined timing, the CPU starts a process from a step  2000  of the routine shown in  FIG. 20  and proceeds with the process to a step  2001  to determine whether the value of the second flag X 2  is “1”. When the value of the second flag X 2  is not “1”, the CPU determines “No” at the step  2001  and proceeds with the process directly to a step  2095  to terminate the process of this routine once. 
     When there is at least one control target vehicle, and the value of the second flag X 2  is “1”, the CPU determines “Yes” at the step  2001  and proceeds with the process to a step  2002  to determine whether the predetermined PCS execution condition is satisfied. In particular, the CPU determines whether the first index value Tc is smaller than or equal to the predetermined first time threshold Tcth. When the predetermined PCS execution condition is not satisfied, the CPU determines “No” at the step  2002  and proceeds with the process directly to the step  2095  to terminate the process of this routine once. 
     On the other hand, when the predetermined PCS execution condition is satisfied, the CPU determines “Yes” at the step  2002  and proceeds with the process to a step  2003  to execute the PCS control. Then, the CPU proceeds with the process to the step  2095  to terminate the process of this routine once. 
     The first apparatus configured as described above selects the control target vehicle, using the area Sa. The area Sa is set, based on change of the positional relationship between the own vehicle SV and the oncoming vehicle which has a high probability of colliding with the own vehicle SV. When the control target candidate vehicle continues to be in the area Sa for the predetermined second time threshold Tmth or more, the own vehicle SV has a high probability of colliding with the control target candidate vehicle in question. In this case, the first apparatus selects the control target candidate vehicle in question as the control target vehicle. Thus, the first apparatus executes the PCS control in an appropriate situation that the own vehicle SV has a high probability of colliding with the oncoming vehicle. On the other hand, in the situations (1) and (2) described above, the first apparatus does not select the oncoming vehicle as the control target vehicle. Thus, the PCS control can be prevented from being executed in a situation that the PCS control should not be executed. 
     Second Embodiment 
     Next, the vehicle control apparatus according to a second embodiment (hereinafter, this vehicle control apparatus will be also referred to as “second apparatus”) will be described. The second apparatus is different from the first apparatus in that the second apparatus changes a size of the area Sa. Below, the difference of the second apparatus from the first apparatus will be mainly described. 
     As shown in  FIG. 21 , the PCS ECU  10  of the second apparatus decreases or reduces the size of the area Sa as the second index value dgt increases. In particular, as the second index value dgt increases, the length Lx of the area Sa in the x-axis direction is decreased or reduced, and the length Ly of the area Sa in the y-axis direction is decreased or reduced (see the area Sa′ and the area Sa″). 
     In addition, while the PCS ECU  10  decreases or reduces the size of the area Sa, the PCS ECU  10  moves the area Sa toward the own vehicle SV in the opposite direction to the turning direction of the own vehicle SV. That is, the PCS ECU  10  moves the area Sa toward the own vehicle SV in the left direction, i.e., the opposite direction to the turning direction, i.e., the right direction of the own vehicle SV. Thus, the size of the area Sa is decreased or reduced, the position of the second side sd 2  and the position of the fourth side sd 4  move toward the own vehicle SV or move in a negative direction of the x-axis, and the position of the first side sd 1  and the position of the third side sd 3  move in the opposite direction to the turning direction of the own vehicle SV or move in a negative direction of the y-axis. 
     As shown in  FIG. 8 , as the second index value dgt increases since the point of time t 1  when the own vehicle SV starts turning, the value of the x-coordinate xi of the position Pi of the first other vehicle OV 1  decreases. That is, the first other vehicle OV 1  gradually approaches the own vehicle SV. If the length Lx of the area Sa in the x-axis direction is relatively great at a point of time when the second index value dgt increases to a great value, the other oncoming vehicle relatively remote from the own vehicle SV, that is, the other vehicle which has a low probability of colliding with the own vehicle SV may be in the area Sa. Thus, the PCS ECU  10  sets the area Sa such that the length Lx of the area Sa in the x-axis direction is decreased as the second index value dgt increases. 
     Further, if the length Ly of the area Sa in the y-axis direction is relatively great at a point of time when the second index value dgt increases to a great value, the other oncoming vehicle which turns, for example, right ahead of the own vehicle SV may be in the area Sa. Thus, the PCS ECU  10  sets the area Sa such that the length Ly of the area Sa in the y-axis direction is decreased as the second index value dgt increases. 
     &lt;Examples of Operations&gt; 
     Processes of selecting the control target vehicle will be described with respect to  FIG. 22  to  FIG. 25 . In an example shown in  FIG. 22 , the own vehicle SV moves in the first moving lane Ln 1  and is turning right in the traffic intersection Is 2 . Further, the first other vehicle OV 1  moves in the first oncoming lane Lo 1 . The first oncoming lane Lo 1  is an oncoming lane for the first moving lane Ln 1 . In this example, the first oncoming lane Lo 1  is a right-turn-only lane. Further, the second other vehicle OV 2  moves in a second oncoming lane Lo 2 . The second oncoming lane Lo 2  is an oncoming lane for the first moving lane Ln 1 . 
     &lt;Point of Time t 11 &gt; 
     As shown in  FIG. 23 , the own vehicle SV starts turning right at a point of time t 11 . The PCS ECU  10  draws the first rectangle  400  which represents the own vehicle SV, the second rectangle  410  which represents the first other vehicle OV 1 , and a third rectangle  420  which represents the second other vehicle OV 2 . The own vehicle SV has a probability of colliding with the first other vehicle OV 1  and the second other vehicle OV 2 . Thus, the PCS ECU  10  selects the first other vehicle OV 1  and the second other vehicle OV 2  as the control target candidate vehicles. 
     Then, the PCS ECU  10  calculates the second index value dgt. Then, the PCS ECU  10  acquires the x-coordinates and the y-coordinates of the four vertexes v 1  to v 4  which define the area Sa by applying the second index value dgt to the predetermined map MP(dgt). Then, the PCS ECU  10  sets the area Sa ahead of the own vehicle SV. The area Sa corresponds to the area Sa shown in  FIG. 21 . The length Lx of the area Sa in the x-axis direction and the length Ly of the area Sa in the y-axis direction are used at a point of time when the own vehicle SV starts turning. The length Lx and the length Ly are set to relatively great values, respectively. In particular, the length Lx in the x-axis direction and the length Ly in the y-axis direction are set to cover the first oncoming lane Lo 1  and the second oncoming lane Lot. Thus, the PCS ECU  10  can be likely to select, as the control target vehicle, the oncoming vehicle, i.e., the second other vehicle OV 2  which moves relatively remote from the own vehicle SV. 
     Hereinafter, the center position of the second rectangle  410  on the two dimension coordinate system will be referred to as “position Pi 1  of the first other vehicle OV 1 ”, and the center position of the third rectangle  420  will be referred to as “position Pi 2  of the second other vehicle OV 2 ”. The position Pi 1  of the first other vehicle OV 1  corresponds to the center position of the front portion of the first other vehicle OV 1  in the width direction of the first other vehicle OV 1 . The position Pi 2  of the second other vehicle OV 2  corresponds to a center position of a front portion of the second other vehicle OV 2  in the width direction of the second other vehicle OV 2 . At the point of time t 11 , the PCS ECU  10  determines that the position Pi 1  of the first other vehicle OV 1  and the position Pi 2  of the second other vehicle OV 2  are in the area Sa. 
     &lt;Point of Time t 12 &gt; 
     As shown in  FIG. 24 , at a point of time t 12  after the point of time t 11 , the own vehicle SV has entered in the traffic intersection Is 2 . At the point of time t 12 , the degree of right turning of the own vehicle SV is greater than the degree of right turning of the own vehicle SV at the point of time t 11 . Thus, the second index value dgt at the point of time t 12  is greater than the second index value dgt at the point of time t 11 . In addition, at the point of time t 12 , the first other vehicle OV 1  has started turning right. 
     As described above, the PCS ECU  10  sets the area Sa ahead of the own vehicle SV by applying the second index value dgt to the map MP(dgt). This area Sa shown in  FIG. 24  corresponds to the area Sa′ shown in  FIG. 21 . At the point of time t 12 , the length Lx of the area Sa in the x-axis direction and the length Ly of the area Sa in the y-axis direction are shorter than the length Lx of the area Sa in the x-axis direction and the length Ly of the area Sa in the y-axis direction at the point of time t 11 . Thereby, the position Pi 1  of the first other vehicle OV 1  which turns right ahead of the own vehicle SV is not in the area Sa. Thus, the PCS ECU  10  determines that the position Pi 1  of the first other vehicle OV 1  is not in the area Sa. On the other hand, the PCS ECU  10  determines that the position Pit of the second other vehicle OV 2  is in the area Sa. 
     &lt;Point of Time t 13 &gt; 
     As shown in  FIG. 25 , at a point of time t 13  after the point of time t 12 , the second other vehicle OV 2  has entered in the traffic intersection Is 2 . Further, at the point of time t 13 , the degree of right turning of the own vehicle SV is greater than the degree of right turning of the own vehicle SV at the point of time t 12 . Thus, the second index value dgt of the own vehicle SV at the point of time t 13  is greater than the second index value dgt of the own vehicle SV at the point of time t 12 . 
     As described above, the PCS ECU  10  sets the area Sa ahead of the own vehicle SV by applying the second index value dgt to the map MP(dgt). This area Sa shown in  FIG. 25  corresponds to the area Sa″ shown in  FIG. 21 . At the point of time t 13 , the length Lx of the area Sa in the x-axis direction and the length Ly of the area Sa in the y-axis direction are shorter than the length Lx of the area Sa in the x-axis direction and the length Ly of the area Sa in the y-axis direction at the point of time t 12 . In this case, the PCS ECU  10  determines that the position Pi 1  of the first other vehicle OV 1  is not in the area Sa. On the other hand, the PCS ECU  10  determines that the position Pi 2  of the second other vehicle OV 2  is in the area Sa. In addition, the predetermined second time threshold Tmth elapses since the point of time t 11 . Thus, the position Pi 2  of the second other vehicle OV 2  continues to be in the area Sa for the predetermined second time threshold Tmth or more. Thus, the PCS ECU  10  determines that the second other vehicle OV 2  satisfies the control target condition. Thus, the PCS ECU  10  selects the second other vehicle OV 2  as the control target vehicle. 
     The second apparatus configured as described above sets the length Lx of the area Sa in the x-axis direction and the length Ly of the area Sa in the y-axis direction to relatively great values, respectively at a point of time when the own vehicle SV starts turning. Thereby, even when the oncoming lanes (the first oncoming lane Lo 1  and the second oncoming lane Lot) are provided on the road, the oncoming vehicle relatively remote from the own vehicle SV, for example, the second other vehicle OV 2  at the point of time t 11  is likely to be selected as the control target vehicle. 
     In addition, the second apparatus sets the area Sa with decreasing or reducing the length Lx of the area Sa in the x-axis direction and the length Ly of the area Sa in the y-axis direction as the second index value dgt increases. Thus, the oncoming vehicle relatively remote from the own vehicle SV is unlikely to be in the area Sa. In addition, the oncoming vehicle turning ahead of the own vehicle SV is unlikely to be in the area Sa. Thus, the PCS control is unlikely to be executed in the situation that the PCS control should not be executed. 
     As another example, the second apparatus may set the area Sa with decreasing or reducing one of the length Lx of the area Sa in the x-axis direction and the length Ly of the area Sa in the y-axis direction as the second index value dgt increases. Also in this case, the PCS control is unlikely to be executed in the situation that the PCS control should not be executed. 
     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. 
     Modified Example 1 
     The CPU may be configured to change the predetermined second time threshold Tmth, depending on the moving speed Vs of the own vehicle SV at the step  1906  of the routine shown in  FIG. 19 . When the moving speed Vs of the own vehicle SV is high, time taken for the own vehicle SV to reach the crossing position Ps is short. Thus, the CPU may be configured to set the predetermined second time threshold Tmth such that the predetermined second time threshold Tmth is decreased as the moving speed Vs of the own vehicle SV increases. Thereby, the CPU can select the control target vehicle at an earlier timing and execute the PCS control at an appropriate timing when the moving speed Vs of the own vehicle SV is high. 
     According to further another example, the CPU may be configured to set the predetermined second time threshold Tmth to a first value T 1  when the moving speed Vs of the own vehicle SV is equal to or smaller than a predetermined speed threshold Vsth. In this case, the CPU may be configured to set the predetermined second time threshold Tmth to a second value T 2  when the moving speed Vs of the own vehicle SV is greater than the predetermined speed threshold Tsth. 
     Modified Example 2 
     The CPU may be configured to acquire the road information from the map storing section  52  and change the size and the position of the area Sa, based on the acquired road information. In this case, for example, the CPU determines whether a particular lane condition is satisfied. The particular lane condition is satisfied when the road on which the oncoming vehicle moves includes a turn-only lane. That is, the particular lane condition is satisfied when the oncoming lanes of the road on which the oncoming vehicle moves includes the turn-only lane. The turn-only lane includes a right-turn-only lane and a left-turn-only lane. When the particular lane condition is satisfied, the CPU sets the area Sa such that the area Sa does not cover the turn-only lane. 
       FIG. 26  shows the same situation as the situation shown in  FIG. 23 . The first oncoming lane Lo 1  is the right-turn-only lane. The CPU may be configured to decrease or reduce the area Sa by decreasing or reducing the length Ly of the area Sa in the y-axis direction by a width Lw of the first oncoming lane Lo 1  at the point of time t 11  when the own vehicle SV starts turning. It should be noted that the CPU can acquire information on the width Lw of the first oncoming lane Lo 1 , based on the road information. Thereby, the first other vehicle OV 1  turning right ahead of the own vehicle SV is unlikely to be in the area Sa. 
     According to further another example, the CPU may be configured to move the area Sa by the width Lw of the first oncoming lane Lo 1  in the positive y-axis direction at the point of time t 11  when the own vehicle SV starts turning. Thereby, the first other vehicle OV 1  turning right ahead of the own vehicle SV is unlikely to be in the area Sa. 
     Modified Example 3 
     The second index value dgt is not limited to ones described above. The second index value dgt may be any value as far as the second index value dgt represents the degree of turning of the own vehicle SV since the turn start point of time. The second index value dgt may be an angle θ which is defined by a predetermined reference axis and the moving direction of the own vehicle SV. The predetermined reference axis is, for example, the moving direction of the own vehicle SV at the turn start point of time. According to another example, the predetermined reference axis may be a direction in which the first moving lane Ln 1  in which the own vehicle SV moves extends. The CPU can acquire the direction in which the first moving lane Ln 1  extends, based on the lane information. 
     According to further another example, the second index value dgt may be an integration value of a particular angle θa since the turn start point of time. The particular angle θa is an angle which is defined by a speed vector at a point of time t and the speed vector at a point of time t+Δt. The particular angle θa takes a positive value when the own vehicle SV turns right. 
     According to further another example, the second index value dgt may be a magnitude of a change amount of the steering angle θ since the turn start point of time. Further, the second index value dgt may be a moving distance of the own vehicle SV since the turn start point of time. 
     Modified Example 4 
     At the step  1904  of the routine shown in  FIG. 19 , the CPU executes a process of determining whether the position Pi of the control target candidate vehicle is in the area Sa. However, the process of the step  1904  is not limited to this process. The CPU may be configured to determine whether at least a part of the rectangle which represents the control target candidate vehicle is in the area Sa. For example, the CPU may be configured to determine whether at least a part of the second rectangle  410  which represents the first other vehicle OV 1  is in the area Sa. 
     Modified Example 5 
     The step  1802  of the routine shown in  FIG. 18  may be omitted. In this case, the CPU executes the routine shown in  FIG. 19  for each object recognized at the step  1801 . The CPU may be configured to select, as the control target vehicle, the object having the position Pi which continues to be in the area Sa for the predetermined second time threshold Tmth or more. 
     Modified Example 6 
     The shape of the area Sa may be any shape other than a quadrangle. The shape of the area Sa may be a triangle or a polygon other than the quadrangle. Further, the shape of the area Sa may be a round shape such as a circle and an oval. When the shape of the area Sa is the round shape, the CPU of the first apparatus moves a center of the round shape toward the own vehicle SV in the opposite direction (the left direction) to the turning direction (the right direction) of the own vehicle SV with maintaining a diameter of the round shape as the second index value dgt increases. When the shape of the area Sa is the round shape, the CPU of the second apparatus may change the diameter of the round shape such that an area of the area Sa is decreased as the second index value dgt increases. 
     Modified Example 7 
     The CPU may be configured to determine whether the own vehicle SV starts turning right, based on information from the navigation ECU  50 . For example, the CPU may be configured to start executing the routines shown in  FIG. 18  to  FIG. 20  when the CPU determines, based on the information from the navigation ECU  50 , that the own vehicle SV approaches the traffic intersection, or the own vehicle SV moves in the right-turn-only lane. 
     Modified Example 8 
     The CPU may be configured to estimate the position of the own vehicle SV in the traffic intersection by communication means such as vehicle to vehicle communication (V2V: Vehicle to Vehicle) or vehicle to infrastructure communication (V2I: Vehicle to Infrastructure). In this case, the CPU may be configured to estimate the second index value dgt, based on the position of the own vehicle SV in the traffic intersection. At a point of time when the own vehicle SV has entered in the traffic intersection Is 1  as in the example shown in  FIG. 6 , the CPU estimates that the second index value dgt is a relatively small value. Then, at a point of time when the own vehicle SV has entered in the first oncoming lane Lo 1  as in the example shown in  FIG. 7 , the CPU estimates that the second index value dgt is a relatively great value. 
     Modified Example 9 
     The first index value which represents a collision probability that the own vehicle SV collides with the control target vehicle, is not limited to ones of the examples described above. The first index value may be a distance ds. For example, the predetermined PCS execution condition may be a condition that the distance ds is equal to or shorter than a predetermined distance threshold dsth. 
     Modified Example 10 
     The embodiments described above are examples applied to countries and regions where the vehicles move to the left side of the road. However, the embodiments described above can be applied to countries and regions where the vehicles move to the right side of the road. In this case, the PCS ECU  10  executes the routines shown in  FIG. 18  to  FIG. 20  after the PCS ECU  10  determines that the own vehicle SV starts turning left. In this case, the PCS ECU  10  moves the area Sa toward the own vehicle SV in the opposite direction (the right direction or the positive direction of the y-axis) to the turning direction (the left direction or the negative direction of the y-axis) of the own vehicle SV as the second index value dgt increases.