Patent Publication Number: US-2022219714-A1

Title: Vehicle control system and vehicle control method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2021-003708 filed on Jan. 13, 2021, incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a system and a method for improving the traveling safety of a first vehicle using communication between the first vehicle that is a host vehicle and a second vehicle that is another vehicle (vehicle-to-vehicle communication; hereinafter, also referred to as “V2V”). 
     2. Description of Related Art 
     Japanese Unexamined Patent Application Publication No. 2019-87076 (JP 2019-87076 A) discloses a system that includes a plurality of vehicles traveling in a platoon and a server that communicates with these vehicles individually. The server of this conventional system detects an abnormal vehicle among the plurality of vehicles based on the behavior information on each vehicle. An abnormal vehicle is detected based on the statistical processing for the behavior information. When an abnormal vehicle is detected, the server identifies an abnormal portion based on the behavior information on the abnormal vehicle that is received from the normal vehicle traveling in front of or behind the abnormal vehicle. An abnormal portion may also be identified using V2V between the abnormal vehicle and the normal vehicle. When an abnormal portion is identified, the server provides the information on the abnormal portion to the abnormal vehicle or the normal vehicle. 
     SUMMARY 
     The information on the abnormal portion is information useful for the abnormal vehicle and the normal vehicle. However, though provided via the server in the conventional system, such information may be provided not via the server. 
     To provide such information not via the server, one possible way is to provide the information, useful for the first vehicle, using V2V performed between the first vehicle that is the host vehicle and the second vehicle that is another vehicle. In particular, since objective information as to whether the first vehicle is traveling abnormally is useful, it is desirable that such information be positively provided from the second vehicle to the first vehicle. However, there is no conventional technique developed from this point of view. 
     The present disclosure provides a new technique that makes it possible to improve the traveling safety of a first vehicle using V2V performed between the first vehicle that is the host vehicle and a second vehicle that is another vehicle. 
     A first disclosure is a vehicle control system that uses communication between a first vehicle and a second vehicle. The first disclosure has the following features. The first vehicle includes a communication device configured to send and receive vehicle-to-vehicle communication information, a memory configured to store the vehicle-to-vehicle communication information, and a processor configured to perform abnormal traveling determination processing for determining whether the first vehicle is travelling abnormally. The second vehicle includes a communication device configured to send and receive the vehicle-to-vehicle communication information, a memory configured to store the vehicle-to-vehicle communication information and driving environment information on the second vehicle, and a processor configured to perform objective determination processing for determining whether the first vehicle is traveling abnormally. The processor of the second vehicle is configured to determine, in the objective determination processing, whether the first vehicle is traveling abnormally based on the driving environment information on the second vehicle, to generate an objective determination result as the vehicle-to-vehicle communication information to be sent to the first vehicle, and to send the objective determination result to the communication device of the second vehicle. The objective determination result indicates the determination result of the objective determination processing. The processor of the first vehicle is configured to determine, in the abnormal traveling determination processing, whether the first vehicle is traveling abnormally based on the objective determination result and, when it is determined that the first vehicle is traveling abnormally, to perform emergency vehicle control for the first vehicle. 
     A second disclosure according to the first disclosure may further have the following features. The memory of the first vehicle may be configured to further store driving environment information on the first vehicle. The abnormal traveling determination processing may be configured to include subjective determination processing for subjectively determining whether the first vehicle is traveling abnormally. The processor of the first vehicle may be configured to determine, in the subjective determination processing, whether the first vehicle is traveling abnormally based on the driving environment information on the first vehicle. The processor of the first vehicle may be configured to comprehensively determine, in the abnormal traveling determination processing, whether the first vehicle is traveling abnormally based on the objective determination result and on a subjective determination result. The subjective determination result indicates the result of the subjective determination processing. 
     A third disclosure according to the second disclosure may further have the following features. The processor of the first vehicle may be configured to comprehensively determine, in the abnormal traveling determination processing, whether the first vehicle is traveling abnormally based on a calculation expression represented using the subjective determination result, the objective determination result, and weighting coefficients of the subjective determination result and the objective determination result. The weighting coefficients may be changed based on the driving environment information on the first vehicle. 
     A fourth disclosure is a vehicle control method that uses communication between a first vehicle and a second vehicle. The fourth disclosure has the following features. The vehicle control method includes, by a processor of the second vehicle, acquiring driving environment information on the second vehicle, performing objective determination processing for objectively determining whether the first vehicle is traveling abnormally based on the driving environment information, and sending an objective determination result to the first vehicle. The objective determination result indicates the result of the objective determination processing. The vehicle control method further includes, by a processor of the first vehicle, receiving the objective determination result, determining whether the first vehicle is traveling abnormally based on the objective determination result, and performing emergency vehicle control for the first vehicle when it is determined that the first vehicle is traveling abnormally. 
     According to the first or fourth disclosure, the processor of the second vehicle performs the objective determination processing and sends the objective determination result to the first vehicle. Based on this objective determination result, the processor of the first vehicle determines whether the first vehicle is traveling abnormally. When it is determined that the first vehicle is traveling abnormally, the first vehicle performs the emergency vehicle control. Therefore, the first or fourth disclosure gives objectivity to the abnormal traveling determination of the first vehicle itself, making it possible to improve the traveling safety of the first vehicle. 
     According to the second disclosure, the processor of the first vehicle performs subjective determination processing and, based on this subjective determination result and on the objective determination result received from the second vehicle, comprehensively determines whether the first vehicle is traveling abnormally. Therefore, the second disclosure makes it possible to reflect the subjective determination result on the abnormal traveling determination of the first vehicle itself. 
     According to the third disclosure, the weighting coefficients of the subjective determination result and the objective determination result are changed based on the driving environment information on the first vehicle. The third disclosure allows the weighting coefficients to be changed in this way, making it possible to change the degree of reflection that the subjective determination result has on the abnormal traveling determination of the first vehicle itself. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein: 
         FIG. 1  is a diagram showing an example of V2V performed in a vehicle control system according to an embodiment; 
         FIG. 2  is a diagram showing an application example of the embodiment; 
         FIG. 3  is a diagram showing an application example of the embodiment; 
         FIG. 4  is a diagram showing another application example of the embodiment; 
         FIG. 5  is a diagram showing another application example of the embodiment; 
         FIG. 6  is a block diagram showing an example of the configuration of the vehicle control system according to the embodiment; 
         FIG. 7  is a flowchart showing the flow of a processing example performed by a control device (processor) of a second vehicle; 
         FIG. 8  is a flowchart showing the flow of a processing example performed by a control device (processor) of a first vehicle; and 
         FIG. 9  is a flowchart showing the flow of another processing example performed by the control device (processor) of the first vehicle. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     A vehicle control system and a vehicle control method according to an embodiment of the present disclosure will be described below with reference to the drawings. The vehicle control method according to the embodiment is implemented by the computer processing performed in the vehicle control system according to the embodiment. Note that, in the figures, the same reference numerals will be given to the same or similar components and the description thereof will be simplified or omitted. 
     1. Outline of Embodiment 
     1-1. V2V 
       FIG. 1  is a diagram showing an example of V2V performed in the embodiment.  FIG. 1  shows a first vehicle M 1  traveling in a lane L 1 . A plurality of second vehicles M 2  is traveling around the first vehicle M 1 . One second vehicle M 2  traveling in the lane L 1  is a following vehicle traveling behind the first vehicle M 1  in the same direction as the traveling direction of the first vehicle M 1 . Two second vehicles M 2  traveling in a lane L 2  are oncoming vehicles traveling in the direction opposite to the traveling direction of the first vehicle M 1 . 
     The X direction shown in  FIG. 1  is the traveling direction of the first vehicle M 1 , and the Y direction is a plane direction orthogonal to the X direction. Note that the coordinate system (X, Y) is not limited to this example. The first vehicle M 1  includes a control system  10 . Each of the second vehicles M 2  includes a control system  20 . The control system  10  and the control systems  20  make up the vehicle control system according to the embodiment. 
     The control system  10  and each of the control systems  20  are configured to be able to communicate with each other. In the communication between the control system  10  and the control system  20 , various types of V2V information are exchanged. Examples of the V2V information include the identification information (hereinafter, also referred to as “ID information”) on the first vehicle M 1  and the second vehicle M 2 . By receiving the ID information on the second vehicle M 2 , the first vehicle M 1  recognizes the second vehicle M 2  as a vehicle capable of V2V. By receiving the ID information on the first vehicle M 1 , the second vehicle M 2  recognizes the first vehicle M 1  as a vehicle capable of V2V. 
     The V2V information may include the driving situation information on the first vehicle M 1  and the second vehicle M 2 . Examples of the driving situation information include the speed information, traveling direction information, and position information. The position information is composed, for example, of latitude and longitude information. For example, when the V2V information includes the driving situation information on the first vehicle M 1  and when the second vehicle M 2  has the map information, the second vehicle M 2  uses this information to recognize the specific driving situation of the first vehicle M 1 . Examples of the specific driving situation include the lane in which the first vehicle M 1  is currently traveling, the distance from the second vehicle M 2  to the first vehicle M 1 , and the relative speed of the second vehicle M 2  with respect to the first vehicle M 1 . 
     1-2. Abnormal Traveling Determination 
       FIG. 2  and  FIG. 3  are diagrams showing an application example of the embodiment. The first vehicle M 1  and the second vehicles M 2  shown in  FIG. 2  correspond to those shown in  FIG. 1 .  FIG. 2  differs from  FIG. 1  in that the traveling state of the first vehicle M 1  shown in  FIG. 2  is abnormal. The “abnormal traveling state” of the first vehicle M 1  includes the traveling state in which the vehicle greatly exceeds the legal speed (speeding state), the traveling state in which the vehicle meanders across multiple lanes (meandering driving state), the traveling state in which the vehicle travels in the direction opposite to the traveling direction indicated by the lane (wrong-way driving state), and the traveling state in which the vehicle ignores the traffic light (red-light driving state). 
     The abnormal traveling state of the first vehicle M 1  is detected by the abnormal traveling determination performed by the second vehicle M 2  (control system  20 ). In the abnormal traveling determination, whether the traveling state of the first vehicle M 1  is abnormal is determined based on the “driving environment information” on the second vehicle M 2 . The driving environment information on the second vehicle M 2  includes the traveling situation information on the first vehicle M 1  acquired by the external sensor (radar sensor, camera, etc.) provided in the control system  20 . Therefore, with the use of the driving environment information on the second vehicle M 2 , whether the traveling state of the first vehicle M 1  is abnormal is “objectively” determined. In the description below, the processing performed by the control system  20  to determine whether the first vehicle M 1  is traveling abnormally is also referred to as “objective determination.” 
     When the V2V information includes the driving situation information on the first vehicle M 1 , this driving situation information may be combined with the above-described traveling situation information, received from the external sensor, to make objective determination. When the second vehicle M 2  includes the map information, this map information may be combined with the above-described traveling situation information on the first vehicle M 1 , received from the external sensor, to make objective determination. In this case, the map information on the second vehicle M 2  is included in the driving environment information on the second vehicle M 2 . 
     As shown in  FIG. 3 , the result of each of the objective determinations (hereinafter, also referred to as “objective determination result”) RO is provided to the first vehicle M 1  via V2V. The objective determination result RO is, more specifically, a normality determination result NM or an abnormality determination result ANM. In the example shown in  FIG. 3 , the objective determination results ROs of two vehicles are each the abnormality determination result ANM, and the objective determination result RO of one vehicle is the normality determination result NM. These results are sent to the first vehicle M 1  as the V2V information. 
     When the objective determination results ROs are received, the first vehicle M 1  (control system  10 ) determines whether the first vehicle M 1  itself is traveling abnormally based on the objective determination results ROs. This determination is made, for example, by determining whether the following expression (1) of the determination index Z is satisfied. 
         Z =Σ(1/ Nro ) Yi≥TH 1  (1)
 
     In expression (1), Nro is the total number of received objective determination results Ros. The variable Yi (1≤i≤Nro) is 0 for the normality determination result NM, and is 1 for the abnormality determination result ANM. The threshold value TH1 is a numerical value satisfying 0.5≤TH1&lt;1.0. The threshold value TH1 is set in advance. 
     When it is determined that expression (1) is satisfied, the control system  10  performs the emergency vehicle control for the first vehicle M 1 . By performing the emergency vehicle control, the abnormal traveling state of the first vehicle M 1  is resolved. 
     Examples of the emergency vehicle control include deceleration traveling control and limp-home traveling control. In the deceleration traveling control, the control amount of the braking actuator of the first vehicle M 1  is set, for example, so that the first vehicle M 1  decelerates at the predetermined target deceleration (for example, −0.1 G). In the limp-home traveling control, the control amount of the steering actuator and the control amount of the braking actuator of the first vehicle M 1  are set, for example, so that the first vehicle M 1  stops on the shoulder of lane L 1 . 
       FIG. 4  and  FIG. 5  are diagrams showing another application example of the vehicle control system according to the embodiment. The premise of the example shown in  FIG. 4  and that of the example shown in  FIG. 2  are the same.  FIG. 4  differs from  FIG. 2  in that the first vehicle M 1  shown in  FIG. 4  determines whether its own traveling state is abnormal based on its own “driving environment information.” The driving environment information on the first vehicle M 1  includes the traveling situation information on the first vehicle M 1  acquired by the external sensors (radar sensor, camera, etc.) provided in the control system  10 . The driving environment information on the first vehicle M 1  also includes the map information provided by the first vehicle M 1 . 
     When the driving environment information on the first vehicle M 1  is used, whether the traveling state of the first vehicle M 1  is abnormal is “subjectively” determined. In the description below, the determination as to whether the first vehicle M 1  is traveling abnormally, performed by the control system  10 , is referred also to as “subjective determination.” The specific content of the result of the subjective determination RS (hereinafter, also referred to as “subjective determination result”) is the same as that of the objective determination result RO. 
     In the example shown in  FIG. 5 , the subjective determination result RS is the abnormality determination result ANM. The first vehicle M 1  (the control system  10 ), which receives the objective determination results ROs, “comprehensively” determines its own abnormal travelling based on the objective determination results ROs and the subjective determination result RS. This comprehensive determination is made, for example, by determining whether the following expression (2) of the determination index Z is satisfied. 
         Z=αX +βΣ(1/ Nro ) Yi≥TH 2  (2)
 
     In expression (2), the coefficients α and β are weighting coefficients satisfying α+β=1. Each of these coefficients is set in advance. The variable X is 0 for the normality determination result NM, and is 1 for the abnormality determination result ANM. The threshold value TH2 is a numerical value satisfying 0.5≤TH2&lt;1.0. This threshold value is also set in advance. The description of Nro and the variable Yi is the same as that of expression (1). 
     When it is determined that expression (2) is satisfied, the control system  10  performs the emergency vehicle control for the first vehicle M 1 . Specific examples of the emergency vehicle control are the same as those in the example shown in  FIG. 2  and  FIG. 3 . 
     In another example of comprehensive determination, the coefficients α and β of expression (2) may be changed. For example, when the traveling situation information on the first vehicle M 1  clearly indicates that the operating state of the drive actuator (more specifically, electric throttle) of the first vehicle M 1  will continue to deviate significantly from the normal operating state, the coefficient α may be increased (i.e., the coefficient β may be decreased). 
     In still another example of comprehensive determination, when the traveling situation information detected by the external sensor of the first vehicle M 1  clearly indicates that the wrong-way driving state of the first vehicle M 1  will continue, the coefficient α may be increased. When the coefficient α is increased, the degree of reflection is increased that the subjective determination result RS has on the abnormal traveling determination of the first vehicle M 1  itself. Therefore, the emergency vehicle control can be performed more easily than before the coefficient α is increased. 
     According to the embodiment, each of the control systems  20  performs the objective determination and provides the objective determination result RO to the first vehicle M 1  as described above. Then, based on these objective determination results ROs, the control system  10  determines whether the first vehicle M 1  is traveling abnormally. When the control system  10  performs subjective determination, the control system  10  determines whether the first vehicle M 1  is traveling abnormally based on the subjective determination result RS and the objective determination results ROs. 
     When it is determined that the first vehicle M 1  is traveling abnormally, the control system  10  performs emergency vehicle control for the first vehicle M 1 . Therefore, the embodiment gives objectivity to the abnormal travelling determination of the first vehicle M 1  itself, making it possible to improve the traveling safety of the first vehicle M 1 . 
     The vehicle control system and the vehicle control method according to the embodiment will be described below in detail. 
     2. Example of Configuration of Vehicle Control System 
     2-1. Example of Overall Configuration 
       FIG. 6  is a block diagram showing an example of the configuration of the vehicle control system according to the embodiment. As shown in  FIG. 6 , the vehicle control system  100  includes the control system  10  and the control system  20 . The control system  10  is a control system mounted on the first vehicle M 1 . The control system  20  is a control system mounted on the second vehicle M 2 . 
     The control system  10  includes an external sensor  11 , an internal sensor  12 , a Global Navigation Satellite System (GNSS) receiver  13 , and a map database (map DB)  14 . The control system  10  also includes a human machine interface (HMI) unit  15 , various actuators  16 , a communication device  17 , and a control device  18 . 
     The external sensor  11  is a device that detects the surroundings of the first vehicle M 1 . Examples of the external sensor  11  include a radar sensor and a camera. The radar sensor uses radio waves (e.g., millimeter waves) or light to detect targets around the first vehicle M 1 . Targets include static targets and dynamic targets. Examples of static targets include guardrails and buildings. Dynamic targets include pedestrians, bicycles, motorcycles, and vehicles other than the first vehicle M 1 . The camera captures the surroundings of the first vehicle M 1 . 
     The internal sensor  12  is a device that detects the traveling situation of the first vehicle M 1 . Examples of the internal sensor  12  include a vehicle speed sensor, an acceleration sensor, and a yaw rate sensor. The vehicle speed sensor detects the traveling speed of the first vehicle M 1 . The acceleration sensor detects the acceleration of the first vehicle M 1 . The yaw rate sensor detects the yaw rate around the vertical axis of the center of gravity of the first vehicle M 1 . 
     The GNSS receiver  13  is a device that receives signals from three or more artificial satellites. The GNSS receiver  13  is also a device that acquires the position information on the first vehicle M 1 . The GNSS receiver  13  calculates the position and attitude (direction) of the first vehicle M 1  based on the received signals. 
     The map database  14  is a database that stores map information. Examples of the map information include the road position information, road shape information (for example, whether the road is curved or straight), and position information on intersections and structures. The map information also includes traffic regulation information. The map database  14  is formed in an in-vehicle storage device (for example, a hard disk or a flash memory). The map database  14  may be formed in a computer installed in a facility (for example, a management center) capable of communicating with the first vehicle M 1 . 
     The surroundings information acquired by the external sensor  11 , the traveling situation information acquired by the internal sensor  12 , the position and attitude information acquired by the GNSS receiver  13 , and the map information are included in the “driving environment information” on the first vehicle M 1 . 
     The HMI unit  15  is an interface for providing information to the driver of the first vehicle M 1  and for accepting information from this driver. The HMI unit  15  includes, for example, an input device, a display device, a speaker, and a microphone. Examples of the input device include a touch panel, a keyboard, a switch, and a button. The information provided to the driver includes the traveling situation information on the first vehicle M 1  and the V2V information (e.g., ID information, traveling situation information). The information is provided to the driver using the display device and the speaker. The information is accepted from the driver using the input device and the microphone. Whether to accept the objective determination results ROs, received via V2V, is set by an acceptance operation through these devices. 
     The various actuators  16  are actuators included in the traveling device of the first vehicle M 1 . Examples of the various actuators  16  include a drive actuator, a braking actuator, and a steering actuator. The drive actuator drives the first vehicle M 1 . The braking actuator applies braking force to the first vehicle M 1 . The steering actuator steers the tires of the first vehicle M 1 . 
     The communication device  17  is provided with a sending antenna and a receiving antenna for wireless communication with the second vehicles M 2  around the first vehicle M 1 . Wireless communication is performed using, for example, a directional beam composed of a narrow beam formed by a directional sending antenna. When performing V2V using a narrow beam, a synchronization system that performs beam matching using a pilot signal may be used. The frequency of wireless communication may be, for example, several hundred MHz lower than 1 GHz, or may be in a high frequency band equal to or higher than 1 GHz. 
     When performing V2V using a narrow beam, the beam may be synchronized using a pilot signal. For example, the first vehicle M 1  sends a pilot signal to the surrounding vehicles, the surrounding vehicles detect the narrow-beam pilot signal in a wide beam mode or omnidirectional beam mode and, based on the detection result, the direction of the narrow beam of the surrounding vehicles is adjusted. 
     The control device  18  is configured by a microcomputer having at least one processor  18   a  and at least one memory  18   b . At least one program is stored in the memory  18   b . Various types of information including the V2V information and driving environment information are also stored in the memory  18   b . A program is read from the memory  18   b  for execution by the processor  18   a  to implement various functions of the control device  18 . The various functions include the above-described function to perform processing for determining whether the first vehicle M 1  is traveling abnormally. This function also includes the function to perform emergency vehicle control using the various actuators  16 . 
     The control system  20  includes an external sensor  21 , an internal sensor  22 , a GNSS receiver  23 , and a map database  24 . The control system  20  also includes an HMI unit  25 , various actuators  26 , a communication device  27 , and a control device  28 . The control device  28  includes at least one processor  28   a  and at least one memory  28   b . In other words, the basic configuration of the control system  20  is the same as that of the control system  10 . Therefore, for an example of the individual components of the control system  20 , see the description of the control system  10 . 
     The configuration of the control system  20  is not limited to the example shown in  FIG. 6 , and some components may be omitted. For example, the control system  20  does not have to include the GNSS receiver  23  and the map database  24 . 
     2-2. Example of Processing Performed by Control System  20   
       FIG. 7  is a flowchart showing the flow of an example of processing performed by the control device  28  (processor  28   a ). The routine shown in  FIG. 7  is repeatedly performed in a predetermined control cycle. 
     In the routine shown in  FIG. 7 , various types of information are acquired first (step S 11 ). Examples of the various types of information acquired in this step include the V2V information and the driving environment information. Examples of the V2V information include the ID information on the first vehicle M 1 . The V2V information may include the traveling situation information on the first vehicle M 1 . Examples of the driving environment information include the surroundings information from the external sensor  21 , the traveling state information from the internal sensor  22 , the position and attitude information on the second vehicle M 2  acquired by the GNSS receiver  23 , and the map information from the map database  24 . 
     Following step S 11 , the objective determination processing is performed (step S 12 ). The objective determination processing is performed based on the driving environment information acquired in step S 11 . For example, based on the surroundings information (road markings information) or the map information (legal speed information), the legal speed of the lane in which the first vehicle M 1  is currently traveling is recognized. Then, based on the surroundings information, the traveling speed of the first vehicle M 1  is calculated. After that, it is determined whether the calculated traveling speed greatly exceeds the legal speed. The result of this determination is used to determine whether the first vehicle M 1  is in the speeding state. 
     In another example, the acceleration Ay of the first vehicle M 1  in the lateral direction (Y direction) is calculated based on surroundings information (traveling situation information). After that, it is determined whether the acceleration Ay is increased or decreased repeatedly in a short period of time. The result of this determination is used to determine whether the first vehicle M 1  is in the meandering driving state. 
     In yet another example, the lane in which the first vehicle M 1  is currently traveling is recognized based on the surroundings information (traveling situation information) and the map information. After that, based on the surroundings information (traffic sign information attached to the lane in which the first vehicle M 1  is currently traveling), it is determined whether the direction of traveling of the first vehicle M 1  matches the direction indicated by the lane in which the first vehicle M 1  is currently traveling. The result of this determination is used to determine whether the first vehicle M 1  is in the wrong-way driving state. 
     In yet still another example, the lane in which the first vehicle M 1  is currently traveling is recognized based on surroundings information (traveling situation information) and the map information. In addition, the acceleration Ax in the traveling direction (X direction) of the first vehicle M 1  is calculated based on the surroundings information (traveling situation information). Furthermore, the color of the nearest traffic light in the traveling direction of the first vehicle M 1  is detected or estimated based on surroundings information (traffic light recognition information). After that, based on the color of the traffic light and the depression amount of the acceleration Ax, it is determined whether the first vehicle M 1  is in the red-light driving state. For example, when the acceleration Ax is on the increase even though the traffic light is a stop sign (red), it is determined that the traveling state of the first vehicle M 1  is the red-light driving state. 
     Following step S 12 , the objective determination result RO is generated (step S 13 ). The objective determination result RO is sent to the communication device  27  as the V2V information for transmission to the first vehicle M 1 . 
     2-3. Example of Processing Performed by Control System  10   
       FIG. 8  is a flowchart showing the flow of an example of abnormal traveling determination processing performed by the control device  18  (processor  18   a ). The routine shown in  FIG. 8  is repeatedly performed in a predetermined control cycle. 
     In the routine shown in  FIG. 8 , the V2V information is acquired first (step S 21 ). Examples of the acquired V2V information include the ID information on each of the second vehicles M 2  and the objective determination result RO determined by the second vehicle M 2 . The V2V information may include the traveling situation information on the second vehicle M 2 . 
     Following the processing in step S 21 , it is determined whether the first vehicle M 1  is traveling abnormally (step S 22 ). In the processing in step S 22 , the objective determination results ROs, acquired in step S 21 , and the total number of receptions Nro are substituted into the above expression (1) to calculate the determination index Z. When it is determined that the above expression (1) is not satisfied, the processing ends. 
     When it is determined in the processing in step S 22  that the above expression (1) is satisfied, the emergency vehicle control is performed for the first vehicle M 1  (step S 23 ). Examples of the emergency vehicle control include the deceleration traveling control and the limp-home traveling control. When performing the emergency vehicle control, it is desirable to select either the deceleration traveling control or the limp-home traveling control according to the content of the abnormal traveling. For example, when the traveling state is the speeding state or the red-light driving state, the deceleration traveling control is selected. When the traveling state is the wrong-way driving state or the meandering driving state, the limp-home traveling control is selected. The content of the abnormal traveling is estimated based on the driving environment information on the first vehicle M 1  acquired by the external sensor  11  etc. provided in the control system  10 . 
       FIG. 9  is a flowchart showing the flow of another example of the abnormal driving determination processing performed by the control device  18  (processor  18   a ). The routine shown in  FIG. 9  is repeatedly performed instead of the routine shown in  FIG. 8  in a predetermined control cycle. 
     In the routine shown in  FIG. 9 , the V2V information is acquired first (step S 31 ). The content of the processing performed in step S 31  is the same as the content of the processing performed in step S 21  described with reference to  FIG. 8 . 
     Following the processing in step S 31 , the driving environment information on the first vehicle M 1  is acquired (step S 32 ). This driving environment information is acquired by the external sensor  11  etc. provided in the control system  10 . 
     Following the processing in step S 32 , the subjective determination processing is performed (step S 33 ). The subjective determination processing is performed based on the driving environment information acquired in step S 32 . The content of the subjective determination processing is basically the same as the content of the objective determination processing. 
     Following the processing in step S 33 , it is determined whether the first vehicle M 1  is traveling abnormally (step S 34 ). In the processing in step S 34 , the objective determination results ROs and the total number of receptions Nro, acquired in step S 31 , and the result of the subjective determination processing, performed in step S 33  (that is, the subjective determination result RS), are substituted into the above expression (2) to calculate the determination index Z. When it is determined that the above expression (2) is not satisfied, the processing ends. 
     When it is determined in the processing in step S 34  that the above expression (2) is satisfied, the emergency vehicle control is performed for the first vehicle M 1  (step S 35 ). The content of the processing performed in in step S 35  is the same as the content of the processing performed in step S 23  described with reference to  FIG. 8 . 
     3. Effects 
     According to the embodiment described above, each of the control devices  28  (processor  28   a ) performs the objective determination processing and provides the objective determination result RO to the first vehicle M 1 . Then, based on this objective determination results ROs, the control device  18  (the processor  18   a ) determines whether the first vehicle M 1  is traveling abnormally. When the control device  18  (processor  18   a ) performs the subjective determination processing, the control device  18  (processor  18   a ) determines whether the first vehicle M 1  is traveling abnormally based on the subjective determination result RS and the objective determination results ROs. 
     When it is determined that the first vehicle M 1  is traveling abnormally, the control device  18  performs emergency vehicle control for the first vehicle M 1 . Therefore, the embodiment gives objectivity to the abnormal traveling determination of the first vehicle M 1  itself, making it possible to improve the traveling safety of the first vehicle M 1 .