Determination device, determination method, and program

Abstract

To effectively improve the accuracy of determining tailgating.SOLUTION: A determination device includes: an approaching state determination unit (12) that determines whether a first vehicle (V1) and a second vehicle (V2) are in a predetermined approaching state; a third vehicle determination unit (11) that determines whether or not a third vehicle (V3) traveling in front of the second vehicle (V2) is present; and a tailgating determination unit (16) that does not determine that tailgating is happening when at least one of a first condition that the approaching state determination unit (12) determines that the vehicle is approaching and a second condition that the third vehicle determination unit (11) determines that the third vehicle is not present is not satisfied, and determines that tailgating is happening when the first condition and the second condition are satisfied.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a determination device, a determination method, and a program, and to technologies suitable for determining aggressive driving of a vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses a device that determines whether another vehicle is tailgating the vehicle. The device described in Patent Document 1 determines whether another vehicle is tailgating the vehicle based on the duration or number of times that the inter-vehicle distance between the vehicle and the other vehicle is equal to or less than a predetermined distance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-201753 A Summary of the Invention

[0004] The distance between the vehicle and the other vehicle may be shortened even if the driver of the other vehicle does not intend to tailgate, depending on the conditions of the road on which the vehicle and the other vehicle are traveling, etc. For this reason, if the driver of the other vehicle judges whether tailgate driving is occurring simply based on the distance between the vehicle and the other vehicle, as in the device described in Patent Document 1, there is a possibility that the driver may erroneously judge that the other vehicle is tailgate driving even when the other vehicle is not actually tailgate driving, and it can be said that there is room for improvement in the judgment accuracy.

[0005] The present disclosure has been made to solve the above-mentioned problems. That is, one of the objectives of the present disclosure is to effectively improve the accuracy of determining tailgating.

[0006] The device of the present disclosure comprises: A determination device (1) for determining whether a second vehicle (V2) traveling in front of a first vehicle (V1) is tailgating the first vehicle (V1), an approach state determination unit (12) that determines whether the first vehicle (V1) and the second vehicle (V2) are in a predetermined approach state; a third vehicle determination unit (11) that determines whether or not a third vehicle (V3) traveling ahead of the second vehicle (V2) is present; The vehicle is equipped with a tailgating determination unit (16) that does not determine that tailgating is occurring when at least one of a first condition under which the approach state determination unit (12) determines that the vehicle is in the approach state and a second condition under which the third vehicle acquisition unit (11) determines that the third vehicle (V3) does not exist is not met, and that determines that tailgating is occurring when the first condition and the second condition are met.

[0007] The method of the present disclosure comprises: A method for determining whether a second vehicle (V2) traveling in front of a first vehicle (V1) is tailgating the first vehicle (V1), comprising: determining whether the first vehicle (V1) and the second vehicle (V2) are in a predetermined approaching state; determining whether or not a third vehicle (V3) is present traveling ahead of the second vehicle (V2); If at least one of the first condition for determining that the vehicle is approaching and the second condition for determining that the third vehicle (V3) is not present is not met, it is not determined that tailgating is occurring, and if both the first condition and the second condition are met, it is determined that tailgating is occurring.

[0008] The program of the present disclosure is A computer (10) of a determination device (1) that determines whether a second vehicle (V2) traveling in front of a first vehicle (V1) is tailgating the first vehicle (V1), determining whether the first vehicle (V1) and the second vehicle (V2) are in a predetermined approaching state; determining whether or not a third vehicle (V3) is present traveling ahead of the second vehicle (V2); If at least one of the first condition for determining that the vehicle is approaching and the second condition for determining that the third vehicle (V3) is not present is not met, it is not determined that tailgating is occurring, and if the first condition and the second condition are met, a process is executed to determine that tailgating is occurring.

[0009] According to the above configuration, by determining whether tailgating is occurring by taking into consideration not only the approaching state of the first vehicle (V1) and the second vehicle (V2) but also the presence of the third vehicle (V3) traveling in front of the second vehicle (V2), it is possible to effectively improve the accuracy of determination compared to conventional determination methods based only on the distance between vehicles.

[0010] In another aspect of the present disclosure, The approach state determination unit (12) When the time during which the inter-vehicle distance (D) is less than or equal to a predetermined threshold distance (D1) continues for more than a predetermined first threshold time (T1), or when the number of times that the inter-vehicle distance (D) is less than or equal to the threshold distance (D1) reaches a predetermined threshold number (N1) within a predetermined second threshold time (T2), it is determined that the two vehicles are in the approaching state.

[0011] According to this aspect, it is possible to effectively determine that the first vehicle (V1) and the second vehicle (V2) are in an approaching state.

[0012] In another aspect of the present disclosure, The approach state determination unit (12) When the number of decelerations (Nb) of the second vehicle (V2) reaches a predetermined number of decelerations (Nb1) within a predetermined time (T3), it is determined that the second vehicle (V2) is in the approaching state.

[0013] According to the present embodiment, by determining whether tailgating is occurring by taking into account the deceleration frequency of the second vehicle (V2), it becomes possible to effectively detect tailgating that cannot be detected by a determination method based solely on the inter-vehicle distance (D), thereby reliably improving the determination accuracy.

[0014] In another aspect of the present disclosure, The approach state determination unit (12) The number of times the brake lamps of the second vehicle (V2) blink is obtained, and the obtained number of times the brake lamps blink is set as the number of times (Nb) the second vehicle (V2) decelerates.

[0015] According to this aspect, by acquiring the number of times the brake lamps of the second vehicle (V2) flash, it is possible to accurately grasp the number of times (Nb) the second vehicle (V2) decelerates.

[0016] In another aspect of the present disclosure, The tailgating driving determination unit (16) When the first condition and the second condition are met and the minimum speed set for the road on which the first vehicle (V1) and the second vehicle (V2) are traveling is obtained, if the vehicle speed (v) of the first vehicle (V1) or the second vehicle (V2) is equal to or higher than the minimum speed, it is not determined that tailgating is occurring, but if the vehicle speed (v) of the first vehicle (V1) or the second vehicle (V2) drops below the minimum speed, it is determined that tailgating is occurring.

[0017] According to this aspect, when the first vehicle (V1) and the second vehicle (V2) are approaching each other in the absence of the third vehicle (V3), and the vehicle speed (v) of the first vehicle (V1) or the second vehicle (V2) is lower than the minimum speed, it is determined that tailgating is occurring. This makes it possible to accurately detect a situation in which the second vehicle (V2) is intentionally obstructing the travel of the first vehicle (V1), and reliably improves the accuracy of determining tailgating.

[0018] In another aspect of the present disclosure, The tailgating driving determination unit (16) After the first condition and the second condition are satisfied, when at least one of the first vehicle (V1) or the second vehicle (V2) stops in a state of close proximity to each other, if the stopped location is other than a no-parking zone, it is not determined that tailgating is occurring, but if the stopped location is a no-parking zone, it is determined that tailgating is occurring.

[0019] According to this aspect, when the first vehicle (V1) and the second vehicle (V2) approach each other in the absence of the third vehicle (V3), and at least one of the first vehicle (V1) and the second vehicle (V2) stops in a no-parking zone, it is determined that tailgating is occurring. This makes it possible to accurately detect a situation in which the second vehicle (V2) intentionally obstructs the travel of the first vehicle (V1) and forces the first vehicle (V1) to stop, thereby reliably improving the accuracy of determining tailgating.

[0020] Another device of the present disclosure is A determination device (1) for determining whether a second vehicle (V2) traveling in front of a first vehicle (V1) is tailgating the first vehicle (V1), an approach state determination unit (12) that determines that the first vehicle (V1) and the second vehicle (V2) are in a predetermined approach state when the number of decelerations of the second vehicle (V2) reaches a predetermined number within a predetermined time; The vehicle is provided with a tailgating determination unit (16) which determines that tailgating is occurring when the approach state determination unit (12) determines that the vehicle is in the approach state.

[0021] According to the present embodiment, by determining whether tailgating is occurring based on the deceleration frequency of the second vehicle (V2), it becomes possible to effectively detect tailgating that cannot be detected by a determination method based solely on the vehicle-to-vehicle distance, thereby reliably improving the determination accuracy.

[0022] In the above description, in order to facilitate understanding of the invention, the symbols used in the embodiments are added in parentheses to the constituent conditions of the invention corresponding to the embodiments, but each constituent condition of the invention is not limited to the embodiment defined by the said symbols. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic overall configuration diagram of a determination device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram illustrating the relationship between the host vehicle, a preceding vehicle, and a vehicle ahead of the preceding vehicle. [Diagram 3] 1 is a flowchart illustrating a routine for the tailgating determination process of this embodiment. [Figure 4] 13 is a flowchart illustrating a routine for a tailgating determination process according to a modified example. [Diagram 5] 13 is a flowchart illustrating a routine for a tailgating determination process according to a modified example. [Figure 6] 13 is a flowchart illustrating a routine for a tailgating determination process according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, a determination device, a determination method, and a program according to the present embodiment will be described with reference to the drawings. The same components are denoted by the same reference numerals, and also have the same names and functions. Therefore, detailed description thereof will not be repeated.

[0025] [Overall configuration] 1 is a schematic overall configuration diagram of a determination device 1 according to this embodiment. The determination device 1 is mounted on a vehicle V1. The vehicle V1 on which the determination device 1 is mounted is hereinafter referred to as a "host vehicle" in order to distinguish it from other vehicles.

[0026] 1 determines whether another vehicle is tailgating the host vehicle V1. In this embodiment, tailgating refers to dangerous driving in which another vehicle traveling in front of the host vehicle 1 intentionally obstructs the traveling of the host vehicle V1 or tries to force the host vehicle V1 to stop while traveling.

[0027] The determination device 1 has an ECU 10. The ECU 10 has a microcomputer as a main part. ECU is an abbreviation for Electronic Control Unit. The microcomputer includes a CPU, a ROM, a RAM, an interface, etc., and the CPU realizes various functions by executing instructions (programs, routines) stored in the ROM.

[0028] The ECU 10 is a control device that performs tailgating determination processing to determine whether another vehicle traveling in front of the vehicle V1 is tailgating the vehicle V1. To this end, the ECU 10 is communicatively connected to a vehicle state acquisition device 20, a surrounding recognition device 30, a navigation system 40, an HMI (Human Machine Interface) 50, a drive recorder 60, and the like.

[0029] The vehicle state acquisition device 20 is a group of sensors that acquires the state of the host vehicle V1. Specifically, the vehicle state acquisition device 20 includes a vehicle speed sensor 21, an accelerator sensor 22, a brake sensor 23, and the like.

[0030] The vehicle speed sensor 21 detects the traveling speed (vehicle speed v) of the host vehicle V1 and transmits the detected vehicle speed v to the ECU 10. The vehicle speed sensor 21 may be a wheel speed sensor. The accelerator sensor 22 detects the amount of operation of an accelerator pedal (not shown) by the driver and transmits the detected amount of accelerator operation to the ECU 10. The brake sensor 23 detects the amount of operation of a brake pedal (not shown) by the driver and transmits the detected amount of brake operation to the ECU 10.

[0031] The surroundings recognition device 30 is a type of sensor that acquires target information related to targets around the host vehicle V1. Specifically, the surroundings recognition device 30 includes a camera 31, a radar sensor 32, an ultrasonic sensor 33, etc. The target information around the host vehicle V1 acquired by the surroundings recognition device 30 is transmitted to the ECU 10.

[0032] The camera 31 is disposed, for example, on the upper part of the front windshield glass of the host vehicle V1. The camera 31 is, for example, a stereo camera or a monocular camera, and a digital camera having an imaging element such as a CMOS or a CCD can be used. The camera 31 captures an image of the area in front of the host vehicle V1 and acquires target information in front of the host vehicle V1 by processing the captured image data. The target information is information representing the type of target detected in front of the host vehicle V1, the relative distance between the host vehicle V1 and the target, the relative speed between the host vehicle V1 and the target, and the like. The type of target may be recognized, for example, by machine learning such as pattern matching. In this embodiment, the camera 31 acquires, as target information, in particular, a preceding vehicle traveling in front of the host vehicle V1, a preceding vehicle traveling in front of the preceding vehicle, and the illumination of the brake lights of the preceding vehicle.

[0033] The radar sensor 32 is provided, for example, at the front end of the host vehicle V1, and detects a target present in the area ahead of the host vehicle V1. The radar sensor 32 includes a millimeter wave radar and / or a lidar. The millimeter wave radar emits radio waves (millimeter waves) in the millimeter wave band, and receives millimeter waves (reflected waves) reflected by a target present within the emission range. The millimeter wave radar acquires the relative distance between the host vehicle V1 and the target, the relative speed between the host vehicle V1 and the target, and the like, based on the phase difference between the transmitted millimeter wave and the received reflected wave, the attenuation level of the reflected wave, and the time from transmitting the millimeter wave to receiving the reflected wave, and the like. The lidar sequentially scans a pulsed laser light having a shorter wavelength than the millimeter wave in multiple directions, and receives the reflected light reflected by the target, thereby acquiring the shape of the target detected ahead of the host vehicle V1, the relative distance between the host vehicle V1 and the target, the relative speed between the host vehicle V1 and the target, and the like. In this embodiment, the radar sensor 32 acquires, as the target information, in particular, the relative distance (inter-vehicle distance) between the host vehicle V1 and a preceding vehicle traveling ahead of the host vehicle V1.

[0034] The ultrasonic sensor 33 transmits ultrasonic waves in a pulsed manner to a predetermined range around the host vehicle V1 and receives the reflected waves reflected by a three-dimensional object. The ultrasonic sensor 33 acquires target information indicating a reflection point, which is a point on a three-dimensional object where the transmitted ultrasonic waves are reflected, and a distance from the ultrasonic sensor 33, based on the time from transmission to reception of the ultrasonic waves. In this embodiment, the ultrasonic sensor 33 acquires, as the target information, in particular, a relative distance (inter-vehicle distance) between the host vehicle V1 and a preceding vehicle traveling ahead of the host vehicle V1.

[0035] The navigation system 40 includes a GPS (Global Position System) receiver 41. The GPS receiver 41 receives GPS signals from a plurality of artificial satellites, and acquires the current position (latitude and longitude) of the vehicle V1 based on the received plurality of GPS signals. The GPS receiver 41 transmits the acquired current position of the vehicle V1 to the ECU 10. The navigation system 40 also includes a VICS (Vehicle Information and Communication System (registered trademark)) receiver 42 that acquires road congestion information, road regulation information due to construction and accidents, and the like transmitted from VICS. The navigation system 40 also stores a map database 43. The map database 43 is a database that stores highly accurate map information. The map information includes road position information and road types (e.g., general roads, expressways, etc.). The map information also includes sign information installed on the road (e.g., no parking and stopping zones, legal speed limits, etc.). The map database 43 may be provided in an information processing device of a facility (e.g., a management center, etc.) that can communicate with the vehicle V1.

[0036] The HMI 50 is an interface for inputting and outputting information between the driver of the vehicle V1 and the ECU 10, and includes an input device and an output device. Examples of the input device include a touch panel, a switch, and a voice recognition microphone. Examples of the output device include a display 51 and a speaker 52. The display 51 is, for example, a multi-information display, a head-up display, or a display of the navigation system 40. The speaker 52 is, for example, a speaker of an audio system or a speaker of the navigation system 40.

[0037] The drive recorder 60 includes a front camera 61 and a memory 62. The front camera 61 is attached to the cabin side of the windshield (not shown) of the vehicle V1, for example, and captures a front image of the vehicle V1. The front camera 61 may be a camera shared with the camera 31 of the surrounding recognition device 30. The memory 62 records image data captured by the front camera 61. The drive recorder 60 may be a continuous recording type in which image data captured by the front camera 61 is stored in the memory 62 one by one and overwritten appropriately in order from the oldest to the newest depending on the storage capacity of the memory 62, or an event recording type in which, when a predetermined event occurs in the vehicle V1, image data captured by the front camera 61 during a predetermined period before and after the event occurs is recorded in the memory 62, or a hybrid type having features of both the continuous recording type and the event recording type by dividing the recording area of ​​the memory 62 into a continuous recording area and an event recording area and lowering the resolution of the image for the continuous recording area.

[0038] [Tailgating driving detection processing] Next, the tailgating determination process will be described. Focusing on its functions, the ECU 10 has a forward vehicle determination unit 11, an approach state determination unit 12, a regulation information acquisition unit 14, a collision prediction determination unit 15, and an arbitration unit 16 as some of its functional elements. These functional elements will be described as being included in the ECU 10, which is an integrated piece of hardware, but any of these may be provided in an ECU separate from the ECU 10. In addition, all or some of the functional elements of the ECU 10 may be provided in an information processing device in a facility (e.g., a management center) capable of communicating with the vehicle V1.

[0039] The forward vehicle determination unit 11 determines whether or not there is a preceding vehicle traveling ahead of the vehicle V1 based on the detection result of the surrounding recognition device 30, and when it is determined that there is a preceding vehicle, it determines whether or not there is a preceding vehicle traveling ahead of the preceding vehicle. Here, the preceding vehicle refers to the vehicle V2 traveling just before the vehicle V1 among other vehicles traveling in the same lane as the vehicle V1, as shown in FIG. 2. The preceding vehicle refers to the vehicle V3 traveling just before the vehicle V2 among other vehicles traveling in the same lane as the vehicle V1 and the preceding vehicle V2. The presence of the preceding vehicle V2 and the preceding vehicle V3 can be acquired using a known method based on the detection result of the camera 31, the radar sensor 32, etc. of the surrounding recognition device 30. The forward vehicle determination unit 11 only needs to determine whether or not there is the preceding vehicle V2 or the preceding vehicle V3, and does not need to acquire the relative distance or relative speed with respect to the vehicle V1. The judgment result by the forward vehicle determination unit 11 is transmitted to the arbitration unit 16.

[0040] The approach state determination unit 12 includes a vehicle distance determination unit 12a and a deceleration frequency determination unit 12b, and determines whether or not the host vehicle V1 and the preceding vehicle V2 are in a predetermined approach state based on the determination results of these determination units 12a, 12b.

[0041] The inter-vehicle distance determination unit 12a determines whether the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state based on the detection result of the surrounding recognition device 30. Specifically, the inter-vehicle distance determination unit 12a determines that the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state when the time during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 acquired by the surrounding recognition device 30 is equal to or less than the predetermined threshold distance D1 continues for a predetermined first threshold time T1 or more. In addition, the inter-vehicle distance determination unit 12a determines that the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state when the number of times N during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 acquired by the surrounding recognition device 30 is equal to or less than the predetermined threshold distance D1 reaches a predetermined threshold number of times N1 within a predetermined second threshold time T2. The threshold distance D1, the first threshold time T1, the threshold number of times N1, and the second threshold time T2 used in the judgment may be fixed values, or may be variable values ​​set according to the vehicle speed v of the host vehicle V1 and the type of road on which the host vehicle V1 is traveling (general road, expressway, etc.). When the vehicle distance judgment unit 12a judges that the vehicle distance D is in a predetermined shortened state, the approach state judgment unit 12 judges that the host vehicle V1 and the preceding vehicle V2 are in a predetermined approach state, and transmits the judgment result to the arbitration unit 16.

[0042] The deceleration frequency determination unit 12b determines whether the deceleration frequency of the preceding vehicle V2 is high based on the detection result of the surrounding recognition device 30. Specifically, when the deceleration frequency Nb of the preceding vehicle V2 reaches a predetermined number Nb1 within a predetermined third threshold time T3, the deceleration frequency determination unit 12b determines that the deceleration frequency of the preceding vehicle V2 is high. The deceleration frequency Nb of the preceding vehicle V2 may be counted, for example, by detecting the number of times that the brake lamp or high mount stop lamp of the preceding vehicle V2 blinks. The blinking of the brake lamp or high mount stop lamp may be acquired by performing machine learning such as pattern matching based on image data of the brake lamp or high mount stop lamp of the preceding vehicle V2 captured by the camera 31. The third threshold time T3 and the predetermined number Nb1 used for the determination may be fixed values, or may be variable values ​​set according to the vehicle speed v of the host vehicle V1 and the type of road (general road, expressway, etc.) on which the host vehicle V1 is traveling. When the deceleration frequency determination unit 12b determines that the deceleration frequency of the preceding vehicle V2 is high, the approach state determination unit 12 determines that the host vehicle V1 and the preceding vehicle V2 are in a predetermined approach state, and transmits the determination result to the arbitration unit 16.

[0043] The restriction information acquisition unit 14 acquires restriction information for the road on which the vehicle V1 is traveling. Specifically, the restriction information acquisition unit 14 acquires the type of road on which the vehicle V1 is traveling (general road, expressway, etc.) and sign information (no parking and stopping zones, legal minimum speed, etc.) based on the current position of the vehicle V1 detected by the GPS receiver 41 of the navigation system 40 and the map information of the map database 43. In addition, the restriction information acquisition unit 14 acquires restriction information that a construction zone or an accident vehicle exists ahead of the vehicle V1 on the road on which the vehicle V1 is traveling, based on the detection result of the VICS receiver 42. The information acquired by the restriction information acquisition unit 14 is transmitted to the arbitration unit 16.

[0044] The collision prediction determination unit 15 determines whether or not there is a high possibility that the host vehicle V1 will collide with the preceding vehicle V2 based on a collision prediction time TTC, which is a predicted time until the host vehicle V1 collides with the preceding vehicle V2. Here, the collision prediction time TTC is the vehicle distance D between the host vehicle V1 and the preceding vehicle V2 at a certain time point divided by the relative speed vr (TTC=D / vr). The vehicle distance D and the relative speed vr may be acquired based on the detection result of the surrounding recognition device 30. If the collision prediction time TTC decreases to a predetermined determination threshold value TTCv or less, the collision prediction determination unit 15 determines that there is a high possibility that the host vehicle V1 will collide with the preceding vehicle V2. The determination result by the collision prediction determination unit 15 is transmitted to the arbitration unit 16.

[0045] The arbitration unit 16 judges whether the preceding vehicle V2 is tailgating the host vehicle V1 based on inputs from the forward vehicle judgment unit 11, the approach state judgment unit 12, the regulation information acquisition unit 14, and the collision prediction judgment unit 15, and executes arbitration processing to control the operation of the HMI 50 and the drive recorder 60 based on the judgment result. Specific processing contents performed by the arbitration unit 16 will be described below.

[0046] The arbitration unit 16 first judges whether or not a first condition, which is a prerequisite for tailgating, is satisfied based on the input from the approaching state judgment unit 12. When the approaching state judgment unit 12 judges that the host vehicle V1 and the preceding vehicle V2 are in a predetermined approaching state, that is, when the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 is frequently decelerating, the arbitration unit 16 judges that the first condition is satisfied. When the first condition is satisfied, the arbitration unit 16 judges whether or not a second condition, which is a prerequisite for tailgating, is satisfied based on the input from the forward vehicle judgment unit 11. This second condition is satisfied when the preceding vehicle V3 does not exist. When the second condition is not satisfied, that is, when the preceding vehicle V3 exists, the arbitration unit 16 does not judge that tailgating is being performed (or judges that tailgating is not being performed).

[0047] In this way, even if the vehicle distance D between the vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 is frequently decelerating, if the preceding vehicle V3 is present, it is not determined that tailgating is occurring. This effectively prevents the driver of the preceding vehicle V2 from erroneously determining that tailgating is occurring when the driver does not intend to engage in tailgating, for example, when the preceding vehicle V2 decelerates due to the influence of the preceding vehicle V3 due to a traffic jam, and as a result, the vehicle V1 approaches the preceding vehicle V2.

[0048] When the first condition and the second condition are met, the arbitration unit 16 judges whether or not at least any of the third to sixth conditions described below is met. When at least one of the third to sixth conditions is met, the arbitration unit 16 judges that the preceding vehicle V2 is tailgating the host vehicle V1. On the other hand, when none of the third to sixth conditions is met, the arbitration unit 16 does not judge that tailgating is taking place (or judges that tailgating is not taking place). The third to sixth conditions are explained in detail below.

[0049] The third condition is satisfied when the vehicle V1 is traveling on a motorway such as an expressway and the regulation information acquisition unit 14 acquires the legal minimum speed (hereinafter, minimum speed) set for the road on which the vehicle V1 is traveling, and the vehicle speed v of the vehicle V1 acquired by the vehicle speed sensor 21 becomes lower than the minimum speed. If the vehicle distance D between the vehicle V1 and the preceding vehicle V2 becomes shorter or the preceding vehicle V2 frequently and repeatedly decelerates even though there is no preceding vehicle V3, causing the vehicle speed v of the vehicle V1 to become lower than the minimum speed, it is presumed that the driver of the preceding vehicle V2 is intentionally trying to obstruct the traveling of the vehicle V1.

[0050] When the first and second conditions are satisfied and the third condition is satisfied, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the host vehicle V1. That is, when the vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 frequently decelerates and the vehicle speed v of the host vehicle V1 drops below the minimum speed in a state where the preceding vehicle V3 does not exist, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the host vehicle V1. In this way, by determining tailgating in consideration of not only the approach state but also the presence of the preceding vehicle V3 and the minimum speed, it is possible to reliably improve the accuracy of the tailgating determination compared to the conventional determination method based only on the vehicle distance.

[0051] The fourth condition is satisfied when the regulation information acquisition unit 14 does not acquire regulation information indicating that a construction zone or an accident vehicle exists ahead of the vehicle V1 on the road on which the vehicle V1 is traveling. When the vehicle distance D between the vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 repeatedly decelerates frequently in a state where the vehicle V3 ahead of the vehicle V3 does not exist, and when a construction zone or an accident vehicle exists on the road on which the vehicle V1 is traveling, it is considered that the preceding vehicle V2 does not intend to tailgate the vehicle V1, for example, by stopping in front of a broken-down vehicle or by decelerating and traveling through the construction zone. On the other hand, when the vehicle distance D between the vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 repeatedly decelerates in a state where the vehicle V3 ahead of the vehicle V3 does not exist and there is no construction zone or accident vehicle on the road on which the vehicle V1 is traveling, it is presumed that the driver of the preceding vehicle V2 is intentionally trying to obstruct the traveling of the vehicle V1.

[0052] When the first and second conditions are satisfied and the fourth condition is satisfied, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the vehicle V1. That is, when the vehicle distance D between the vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 repeatedly decelerates frequently in a state where the vehicle ahead of the vehicle V3 does not exist, and there is no construction section or accident vehicle on the road on which the vehicle is traveling, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the vehicle V1. In this way, by determining tailgating in consideration of not only the approach state but also the presence of the vehicle ahead of the vehicle V3 and regulation information such as accident vehicles and construction sections, it is possible to reliably improve the accuracy of tailgating determination compared to conventional determination methods based only on the vehicle distance.

[0053] The fifth condition is satisfied when the regulation information acquisition unit 14 acquires that the road on which the host vehicle V1 is traveling is a parking and stopping prohibited section, and at least one of the host vehicle V1 and the preceding vehicle V2 stops in a parking and stopping prohibited section with the vehicle distance D between the host vehicle V1 and the preceding vehicle V2 being equal to or less than a predetermined distance and the degree of closeness is high. Even if the host vehicle V1 or the preceding vehicle V2 stops close to each other, if the location where the host vehicle V1 and the preceding vehicle V2 stop is not a parking and stopping prohibited section, it is considered that the drivers of the host vehicle V1 and the preceding vehicle V2 are acquaintances and intentionally stop on the road shoulder. On the other hand, in a situation where the vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 repeatedly decelerates, and at least one of the host vehicle V1 and the preceding vehicle V2 approaches and stops in a parking and stopping prohibited section even though there is no preceding vehicle V3, it is presumed that the driver of the preceding vehicle V2 intentionally obstructs the travel of the host vehicle V1 and tries to force the host vehicle V1 to stop.

[0054] When the first and second conditions are satisfied and the fifth condition is satisfied, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the host vehicle V1. That is, when the vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 frequently decelerates in a state where at least one of the host vehicle V1 and the preceding vehicle V2 is stopped in a parking and stopping no-section in a state where the degree of approach is high in a state where the preceding vehicle V3 is not present, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the host vehicle V1. In this way, by determining tailgating in consideration of not only the approach state but also the presence of the vehicle V3 before the preceding vehicle V3, and furthermore, the sign information (parking and stopping no-section) of the road where the preceding vehicle V2 and the host vehicle V1 are stopped, the accuracy of the determination can be reliably improved compared to the conventional determination method based only on the vehicle distance.

[0055] The sixth condition is satisfied when the regulation information acquisition unit 14 acquires that the road on which the host vehicle V1 is traveling is a parking and stopping prohibited section, the collision prediction determination unit 14 determines that the possibility of a collision between the preceding vehicle V2 and the host vehicle V1 is high, and at least one of the host vehicle V1 and the preceding vehicle V2 stops in the parking and stopping prohibited section. In a situation in which at least one of the host vehicle V1 and the preceding vehicle V2 stops in the parking and stopping prohibited section in a state in which the distance D between the host vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 frequently decelerates and the collision prediction time TTC is equal to or less than the determination threshold TTCv, even though there is no preceding vehicle V3, it is presumed that the driver of the preceding vehicle V2 is trying to force the host vehicle V1 to stop without regard for the risk of collision.

[0056] When the first and second conditions are satisfied and the sixth condition is satisfied, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the host vehicle V1. That is, when the vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 frequently decelerates and then at least one of the host vehicle V1 and the preceding vehicle V2 stops in a no-parking / stopping section in a state of high approach where the collision prediction time TTC is equal to or less than the judgment threshold TTCv in a situation where the preceding vehicle V3 does not exist, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the host vehicle V1. In this way, by determining tailgating in consideration of not only the approach state but also the presence of the vehicle V3 before the preceding vehicle V3, and further the sign information (no-parking / stopping section) of the road where the preceding vehicle V2 is stopped and the collision prediction time TTC, the judgment accuracy can be reliably improved compared to the conventional judgment method based only on the vehicle distance.

[0057] When the first and second conditions are met, and at least one of the third to sixth conditions is met, the arbitration unit 16 determines that the preceding vehicle V2 is tailgating the host vehicle V1, and activates the HMI 50 and the drive recorder 60.

[0058] Specifically, when the arbitration unit 16 determines that the preceding vehicle V2 is tailgating, it causes the display 51 to display an image informing the driver of the vehicle V1 that the preceding vehicle V2 is tailgating. In addition, the arbitration unit 16 causes the display 51 to display an image for confirming whether or not to notify an external agency such as the police, simultaneously with the notification to the driver. The notification and confirmation to the driver may be performed in combination with audio from the speaker 52, or may be performed only by audio from the speaker 52. The notification to the external agency may be performed by an input device (touch panel, switch, etc.) of the HMI 50 accepting an input operation from the driver, or may be performed by a voice recognition microphone accepting the voice of the driver. Note that the notification to the external agency may be configured to be performed simultaneously when the arbitration unit 16 determines that tailgating is occurring, without requiring confirmation from the driver.

[0059] When the arbitration unit 16 determines that the preceding vehicle V2 is tailgating because the fifth or sixth condition that the vehicle V1 is stopped by the preceding vehicle V2 is satisfied, and the doors of the vehicle V1 are unlocked, the arbitration unit 16 causes the display 51 to display an image that prompts the driver to lock the doors to ensure safety, or an image that prompts the driver to lock the doors. This processing may be performed in conjunction with a voice from the speaker 52, or may be performed only by a voice from the speaker 52. When the arbitration unit 16 causes the display 51 to display an image that prompts the driver to lock the doors, the arbitration unit 16 automatically locks the doors of the vehicle V1 upon receiving a lock instruction from the driver. The lock instruction from the driver may be received by an input device (such as a touch panel) of the HMI 50 or a voice recognition microphone.

[0060] When the arbitration unit 16 determines that the preceding vehicle V2 is tailgating, it causes the drive recorder 60 to record the tailgating behavior of the preceding vehicle V2. Specifically, the arbitration unit 16 stores image data captured by the front camera 61 for a predetermined time before and after the time when tailgating is determined to be occurring in the memory 62 as overwrite-prohibited data. Here, the predetermined time before and after may be a fixed time set in advance, or may be a variable time. If it is a variable time, for example, the predetermined time before and after may be from the time when the arbitration unit 16 detects a symptom of tailgating to the time when it determines that tailgating has ended. As to whether or not there is a symptom of tailgating, for example, it may be determined that there is a symptom of tailgating when the above-mentioned first condition and second condition are satisfied. As to whether or not tailgating has ended, it may be determined that tailgating has ended when the preceding vehicle V2 is away from the host vehicle 1 by a predetermined distance or more.

[0061] Next, a routine for tailgating determination processing by the ECU 10 will be described with reference to the flowchart shown in Fig. 3. This routine is started, for example, when the host vehicle V1 starts traveling.

[0062] In step S100, the ECU 10 determines whether or not a preceding vehicle V2 is present ahead of the host vehicle V1. If the preceding vehicle V2 is present ahead of the host vehicle V1 (Yes), the ECU 10 advances the process to step S110. On the other hand, if the preceding vehicle V2 is not present ahead of the host vehicle V1 (No), the ECU 10 temporarily ends (returns) this routine.

[0063] In step S110, the ECU 10 judges whether the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state. If the time during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than the predetermined threshold distance D1 continues for a predetermined first threshold time T1 or more, or if the number of times N during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than the predetermined threshold distance D1 reaches a predetermined threshold number of times N1 within a predetermined second threshold time T2, the ECU 10 judges that the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state. If the inter-vehicle distance D is in the predetermined shortened state (Yes), the ECU 10 judges that the host vehicle V1 and the preceding vehicle V2 are in a predetermined approaching state, and proceeds to step S130. On the other hand, if the inter-vehicle distance D is not in the predetermined shortened state (No), the ECU 10 proceeds to step S120.

[0064] In step S120, the ECU 10 judges whether the deceleration frequency of the preceding vehicle V2 is high. If the number of decelerations Nb (e.g., the number of times the brake lights are flashed) of the preceding vehicle V2 reaches a predetermined number Nb1 within a predetermined third threshold time T3, the ECU 10 judges that the deceleration frequency of the preceding vehicle V2 is high. If the deceleration frequency of the preceding vehicle V2 is judged to be high (Yes), the ECU 10 judges that the host vehicle V1 and the preceding vehicle V2 are in a predetermined closeness state, and proceeds to step S130. On the other hand, if the deceleration frequency of the preceding vehicle V2 is judged to be not high (No), the ECU 10 does not judge that tailgating is occurring, and once ends (returns) this routine.

[0065] In step S130, the ECU 10 determines that the first condition, which is a prerequisite for tailgating, is satisfied. Next, in step S140, the ECU 10 determines whether or not the vehicle V3 before the preceding vehicle V2 is present ahead of the preceding vehicle V2. If the vehicle V3 before the preceding vehicle V3 is not present (No), the ECU 10 advances the process to step S150. On the other hand, if the vehicle V3 before the preceding vehicle V3 is present (Yes), the ECU 10 does not determine that tailgating is occurring, and once ends (returns) this routine. That is, if the preceding vehicle V2 is decelerating due to the influence of the vehicle V3 before the preceding vehicle V2 due to traffic congestion or the like, the ECU 10 does not determine that tailgating is occurring. This makes it possible to effectively prevent erroneous determinations and reduce the inconvenience to the driver.

[0066] In step S150, the ECU 10 determines that the second condition, which is a prerequisite for tailgating, is satisfied. Next, in step S160, the ECU 10 determines whether or not at least one of the third to sixth conditions is satisfied. Specifically, the ECU 10 determines whether or not at least one of the following conditions is satisfied: a third condition that the vehicle speed v of the host vehicle V1 is lower than the minimum speed; a fourth condition that the host vehicle V1 does not acquire regulation information indicating that a construction section or a broken-down vehicle exists ahead of the host vehicle V1 on the road on which the host vehicle V1 is traveling; a fifth condition that at least one of the host vehicle V1 and the preceding vehicle V2 stops in a parking and stopping prohibited section when the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than a predetermined distance; and a sixth condition that at least one of the host vehicle V1 and the preceding vehicle V2 stops in a parking and stopping prohibited section when the collision prediction time TTC is equal to or less than the judgment threshold TTCv.

[0067] If none of the third to sixth conditions is satisfied (No), the ECU 10 does not determine that tailgating is occurring and ends (returns) this routine for the time being. On the other hand, if one or more of the third to sixth conditions is satisfied (Yes), the ECU 10 proceeds to step S170 and determines that the preceding vehicle V2 is tailgating the host vehicle V1.

[0068] When it is determined in step S170 that tailgating is occurring, the ECU 10 proceeds to processing in step S180 and activates the HMI 50 and the drive recorder 60. Specifically, the ECU 10 causes the display 51 to display an image informing the driver that the preceding vehicle V2 is tailgating the driver and an image for confirming whether or not to report to an external agency. In addition, when the vehicle V1 is stopped due to the establishment of conditions 5 and 6, and the door lock of the vehicle V1 is unlocked, the ECU 10 causes the display 51 to display an image for confirming whether or not the door lock is required and an image for urging the driver to lock the door lock. These notifications and confirmations may be made in combination with audio from the speaker 52, or may be made only by audio from the speaker 52. In addition, the ECU 10 causes the drive recorder 60 to store image data for a predetermined time before and after the time when it is determined that the preceding vehicle V2 is tailgating as overwrite-prohibited data.

[0069] In step S180, the ECU 10 operates the HMI 50 and the drive recorder 60, and then ends this routine.

[0070] According to the present embodiment described above in detail, even if the first condition that the vehicle V1 and the preceding vehicle V2 are in a predetermined approaching state is satisfied, if the second condition is not satisfied, that is, if the preceding vehicle V3 is present, it is configured not to determine that tailgating is occurring. This makes it possible to effectively prevent erroneous determination that tailgating is occurring when the preceding vehicle V2 is not actually tailgating, for example, when the preceding vehicle V2 decelerates due to the influence of the preceding vehicle V3 due to a traffic jam, etc., and the preceding vehicle V2 approaches the vehicle V1 as a result.

[0071] In addition, when the first condition that the host vehicle V1 and the preceding vehicle V2 are in a predetermined approaching state is met and the second condition that the preceding vehicle V3 is not present is met, if at least one of the following conditions is met: the third condition that the vehicle speed v of the host vehicle V1 is slower than the minimum speed; the fourth condition that restriction information indicating that a construction section or broken-down vehicle exists ahead of the host vehicle V1 on the road being traveled is not acquired; the fifth condition that at least one of the host vehicle V1 or the preceding vehicle V2 is stopped in a no parking or stopping section when the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is less than a predetermined distance; and the sixth condition that at least one of the host vehicle V1 or the preceding vehicle V2 is stopped in a no parking or stopping section when the collision prediction time TTC is less than a judgment threshold TTCv, it is determined that the preceding vehicle V2 is tailgating the host vehicle V1.

[0072] That is, when the vehicle distance D between the vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 frequently repeats deceleration in a state where there is no preceding vehicle V3, the system is configured to determine tailgating in consideration of sign information (minimum speed, no parking and stopping zone) and regulation information (accident vehicle, construction zone, etc.) of the road on which the vehicle is traveling. This effectively prevents erroneous determination of tailgating in cases where the preceding vehicle V2 decelerates to ensure safety or where the drivers of the preceding vehicle V2 and the vehicle V1 intentionally stop on the roadside, and reliably improves the determination accuracy. In addition, by preventing erroneous determination, it is possible to effectively reduce the inconvenience to the driver.

[0073] The above describes the determination device, determination method, and program according to the present embodiment, but the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the purpose of the present invention.

[0074] [Variation 1] The first condition, which is a prerequisite for tailgating, may be determined to be met when the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state, without the process of determining whether the preceding vehicle V2 decelerates frequently (step S120 in Figure 3).

[0075] 4 is a flowchart illustrating a routine for tailgating determination processing performed by the ECU 10 in the first modified example. In step S200, the ECU 10 determines whether or not a preceding vehicle V2 is present ahead of the host vehicle V1. If a preceding vehicle V2 is present ahead of the host vehicle V1 (Yes), the ECU 10 advances the processing to step S210. On the other hand, if a preceding vehicle V2 is not present ahead of the host vehicle V1 (No), the ECU 10 temporarily ends (returns) this routine.

[0076] In step S210, the ECU 10 judges whether the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state. If the time during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than the predetermined threshold distance D1 continues for a predetermined first threshold time T1 or more, or if the number of times N during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than the predetermined threshold distance D1 reaches a predetermined threshold number of times N1 within a predetermined second threshold time T2, the ECU 10 judges that the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state. If the inter-vehicle distance D is in the predetermined shortened state (Yes), the ECU 10 judges that the host vehicle V1 and the preceding vehicle V2 are in a predetermined approaching state, and proceeds to step S230. On the other hand, if the inter-vehicle distance D is not in the predetermined shortened state (No), the ECU 10 does not judge that tailgating is occurring, and once ends (returns) this routine.

[0077] In step S230, the ECU 10 determines that the first condition, which is a prerequisite for tailgating, is satisfied. Next, in step S240, the ECU 10 determines whether or not the vehicle V3 before the preceding vehicle V2 is present ahead of the preceding vehicle V2. If the vehicle V3 before the preceding vehicle V3 is not present (No), the ECU 10 advances the process to step S250. On the other hand, if the vehicle V3 before the preceding vehicle V3 is present (Yes), the ECU 10 does not determine that tailgating is occurring and once ends (returns) this routine. That is, it is possible to effectively prevent erroneous determination that tailgating is occurring when the preceding vehicle V2 decelerates due to the influence of the vehicle V3 before the preceding vehicle V2.

[0078] In step S250, the ECU 10 determines that the second condition, which is a prerequisite for tailgating, is satisfied. Next, in step S260, the ECU 10 determines whether or not at least one of the third to sixth conditions is satisfied. Specifically, the ECU 10 determines whether or not at least one of the following conditions is satisfied: a third condition that the vehicle speed v of the host vehicle V1 is lower than the minimum speed; a fourth condition that the host vehicle V1 does not acquire regulation information indicating that a construction section or a broken-down vehicle exists ahead of the host vehicle V1 on the road on which the host vehicle V1 is traveling; a fifth condition that at least one of the host vehicle V1 and the preceding vehicle V2 stops in a parking and stopping prohibited section when the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than a predetermined distance; and a sixth condition that at least one of the host vehicle V1 and the preceding vehicle V2 stops in a parking and stopping prohibited section when the collision prediction time TTC is equal to or less than the judgment threshold TTCv.

[0079] If none of the third to sixth conditions is satisfied (No), the ECU 10 does not determine that tailgating is occurring and ends (returns) this routine for the time being. On the other hand, if one or more of the third to sixth conditions is satisfied (Yes), the ECU 10 proceeds to step S270 and determines that the preceding vehicle V2 is tailgating the host vehicle V1.

[0080] When it is determined in step S270 that tailgating is occurring, the ECU 10 proceeds to processing in step S280, where it activates the HMI 50 and the drive recorder 60. The processing for activating these is similar to that in step S180 in the above embodiment, and therefore detailed description will be omitted. After activating the HMI 50 and the drive recorder 60 in step S280, the ECU 10 then ends this routine.

[0081] According to the above-described modified example 1, when the vehicle distance D between the vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state in a state where the vehicle V3 before ahead does not exist, whether or not the vehicle is tailgating is determined taking into consideration sign information (minimum speed, no parking and stopping zones) and regulation information (accident vehicles, construction zones, etc.) of the road on which the vehicle is traveling. This effectively prevents erroneous determination of tailgating in cases such as when the preceding vehicle V2 decelerates to ensure safety or when the drivers of the preceding vehicle V2 and the vehicle V1 intentionally stop on the roadside, and makes it possible to reliably improve the determination accuracy compared to the conventional determination method based only on the vehicle distance.

[0082] [Variation 2] It is also possible to simplify the determination process as to whether the preceding vehicle V2 is tailgating by omitting the determination process for the third to sixth conditions (step S160 in FIG. 3) and determining based on the satisfaction of the first condition that the host vehicle V1 and the preceding vehicle V2 are in a predetermined close proximity state and the satisfaction of the second condition that the preceding vehicle V3 is not present.

[0083] 5 is a flowchart illustrating a routine for tailgating determination processing performed by the ECU 10 in the second modified example. In step S300, the ECU 10 determines whether or not a preceding vehicle V2 is present ahead of the host vehicle V1. If a preceding vehicle V2 is present ahead of the host vehicle V1 (Yes), the ECU 10 advances the processing to step S310. On the other hand, if a preceding vehicle V2 is not present ahead of the host vehicle V1 (No), the ECU 10 temporarily ends (returns) this routine.

[0084] In step S310, the ECU 10 judges whether the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state. If the time during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than the predetermined threshold distance D1 continues for a predetermined first threshold time T1 or more, or if the number of times N during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than the predetermined threshold distance D1 reaches a predetermined threshold number of times N1 within a predetermined second threshold time T2, the ECU 10 judges that the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state. If the inter-vehicle distance D is in the predetermined shortened state (Yes), the ECU 10 judges that the host vehicle V1 and the preceding vehicle V2 are in a predetermined approaching state, and proceeds to step S330. On the other hand, if the inter-vehicle distance D is not in the predetermined shortened state (No), the ECU 10 proceeds to step S320.

[0085] In step S320, the ECU 10 judges whether the deceleration frequency of the preceding vehicle V2 is high. If the number of decelerations Nb (e.g., the number of times the brake lights are flashed) of the preceding vehicle V2 reaches a predetermined number Nb1 within a predetermined third threshold time T3, the ECU 10 judges that the deceleration frequency of the preceding vehicle V2 is high. If the ECU 10 judges that the deceleration frequency of the preceding vehicle V2 is high (Yes), the ECU 10 advances the process to step S330. On the other hand, if the ECU 10 judges that the deceleration frequency of the preceding vehicle V2 is not high (No), the ECU 10 does not judge that tailgating is occurring and once ends (returns) this routine.

[0086] In step S330, the ECU 10 determines that the first condition is satisfied. Next, in step S340, the ECU 10 determines whether or not the vehicle V3 before the preceding vehicle V2 is present ahead of the preceding vehicle V2. If the vehicle V3 before the preceding vehicle V3 is not present (No), the ECU 10 advances the process to step S350. On the other hand, if the vehicle V3 before the preceding vehicle V3 is present (Yes), the ECU 10 does not determine that tailgating is occurring and once ends (returns) this routine.

[0087] In step S350, the ECU 10 determines that the second condition is satisfied. Next, in step S370, the ECU 10 determines that the preceding vehicle V2 is tailgating the host vehicle V1.

[0088] When it is determined in step S370 that tailgating is occurring, the ECU 10 proceeds to the process of step S280, where it activates the HMI 50 and the drive recorder 60. The process of activating these is similar to that of step S180 in the above embodiment, and therefore a detailed description thereof will be omitted. After activating the HMI 50 and the drive recorder 60 in step S280, the ECU 10 then ends this routine.

[0089] According to the above-described modified example 2, even if the inter-vehicle distance D between the vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 repeatedly decelerates frequently, if the preceding vehicle V3 is present, it is not determined that tailgating is occurring. This effectively prevents erroneous determination that tailgating is occurring when the preceding vehicle V2 is not actually tailgating, for example, when the preceding vehicle V2 decelerates due to the deceleration of the preceding vehicle V3 and approaches the vehicle V1 as a result, and makes it possible to reliably improve the determination accuracy compared to the conventional determination method based only on the inter-vehicle distance.

[0090] [Variation 3] The determination process of whether the preceding vehicle V2 is tailgating can be further simplified by omitting the determination of the second to sixth conditions and determining based on the satisfaction of the first condition, that is, the vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is shortened or the preceding vehicle V2 frequently and repeatedly decelerates.

[0091] 6 is a flowchart illustrating a routine for tailgating determination processing performed by the ECU 10 in the third modified example. In step S400, the ECU 10 determines whether or not a preceding vehicle V2 is present ahead of the host vehicle V1. If a preceding vehicle V2 is present ahead of the host vehicle V1 (Yes), the ECU 10 advances the processing to step S410. On the other hand, if a preceding vehicle V2 is not present ahead of the host vehicle V1 (No), the ECU 10 temporarily ends (returns) this routine.

[0092] In step S410, the ECU 10 judges whether the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state. If the time during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than the predetermined threshold distance D1 continues for a predetermined first threshold time T1 or more, or if the number of times N during which the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is equal to or less than the predetermined threshold distance D1 reaches a predetermined threshold number of times N1 within a predetermined second threshold time T2, the ECU 10 judges that the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is in a predetermined shortened state. If the inter-vehicle distance D is in the predetermined shortened state (Yes), the ECU 10 judges that the host vehicle V1 and the preceding vehicle V2 are in a predetermined approaching state, and proceeds to step S470. On the other hand, if the inter-vehicle distance D is not in the predetermined shortened state (No), the ECU 10 proceeds to step S420.

[0093] In step S420, the ECU 10 judges whether the deceleration frequency of the preceding vehicle V2 is high. If the number of decelerations Nb (e.g., the number of times the brake lights are flashed) of the preceding vehicle V2 reaches a predetermined number Nb1 within a predetermined third threshold time T3, the ECU 10 judges that the deceleration frequency of the preceding vehicle V2 is high. If the deceleration frequency of the preceding vehicle V2 is judged to be high (Yes), the ECU 10 judges that the host vehicle V1 and the preceding vehicle V2 are in a predetermined close proximity state, and proceeds to step S470. On the other hand, if the deceleration frequency of the preceding vehicle V2 is judged to be not high (No), the ECU 10 does not judge that tailgating is occurring, and once ends (returns) this routine.

[0094] In step S470, the ECU 10 determines that the preceding vehicle V2 is tailgating the host vehicle V1. If it is determined in step S470 that tailgating is occurring, the ECU 10 proceeds to processing in step S480, where it activates the HMI 50 and the drive recorder 60. The processing for activating these is similar to that in step S180 in the above embodiment, and therefore detailed description thereof will be omitted. After activating the HMI 50 and the drive recorder 60 in step S480, the ECU 10 then ends this routine.

[0095] According to the above-described modified example 3, even if the inter-vehicle distance D between the host vehicle V1 and the preceding vehicle V2 is not in a predetermined shortened state, if the preceding vehicle V2 decelerates frequently and repeatedly, it is determined that the preceding vehicle V2 is tailgating the host vehicle V1. This makes it possible to determine that an act by the driver of the preceding vehicle V2 that obstructs the travel of the host vehicle V1, such as intentionally repeating braking operations at short intervals, is tailgating, and it is possible to reliably improve the determination accuracy compared to the conventional determination method based only on the inter-vehicle distance.

[0096] [others] In the present disclosure, the determination device 1 has been described as being mounted on the host vehicle V1, but may be mounted on the preceding vehicle V2. In this case, the preceding vehicle V2 in the above embodiment is the host vehicle, the host vehicle V1 is the following vehicle, and the determination device 1 may be configured to determine whether the host vehicle V2 is tailgating the following vehicle V1. The vehicle distance between the host vehicle V2 and the following vehicle V1 may be acquired based on the detection results of a rear camera, a rear radar sensor, etc., mounted on the host vehicle V2. In addition, whether the host vehicle V2 decelerates frequently may be determined based on the number of times the brake pedal is depressed, acquired by a brake sensor, rather than the blinking of the brake lamp. In addition, when it is determined that tailgating is being performed, an image that notifies the driver of the host vehicle V2 that tailgating is being performed or an image that prompts the driver to stop tailgating may be displayed on the display 51. [Explanation of symbols]

[0097] 1...determination device, 10...ECU, 11...forward vehicle determination unit, 12...approach state determination unit, 12a...vehicle distance determination unit, 12b...deceleration frequency determination unit, 14...regulation information acquisition unit, 15...collision prediction determination unit, 16...arbitration unit, 20...vehicle state acquisition device, 30...surrounding recognition device, 40...navigation system, 50...HMI, 60...drive recorder, V1...own vehicle, V2...preceding vehicle, V3...preceding vehicle

Claims

1. A determination device for determining whether a second vehicle traveling in front of a first vehicle is tailgating the first vehicle, an approach state determination unit that determines whether the first vehicle and the second vehicle are in a predetermined approach state; a third vehicle determination unit that determines whether or not a third vehicle is present traveling ahead of the second vehicle; A tailgating driving determination unit that does not determine that tailgating is occurring when at least one of a first condition for the approaching state determination unit to determine that the approaching state is occurring and a second condition for the third vehicle determination unit to determine that the third vehicle does not exist is not satisfied, and that determines that tailgating is occurring when the first condition and the second condition are satisfied, The tailgating driving determination unit is When the first condition and the second condition are satisfied and the minimum speed set for the road on which the first vehicle and the second vehicle are traveling is acquired, if the vehicle speed of the first vehicle or the second vehicle is equal to or higher than the minimum speed, it is not determined that tailgating is occurring, and if the vehicle speed of the first vehicle or the second vehicle is lower than the minimum speed, it is determined that tailgating is occurring. Judgment device.

2. A determination device for determining whether a second vehicle traveling in front of a first vehicle is tailgating the first vehicle, an approach state determination unit that determines whether the first vehicle and the second vehicle are in a predetermined approach state; a third vehicle determination unit that determines whether or not a third vehicle is present traveling ahead of the second vehicle; A tailgating driving determination unit that does not determine that tailgating is occurring when at least one of a first condition for the approaching state determination unit to determine that the approaching state is occurring and a second condition for the third vehicle determination unit to determine that the third vehicle does not exist is not satisfied, and that determines that tailgating is occurring when the first condition and the second condition are satisfied, The tailgating driving determination unit is After the first condition and the second condition are satisfied, when at least one of the first vehicle and the second vehicle stops in a state where the degree of proximity to each other is high, if the place where the vehicle stops is other than a no-parking zone, it is not determined that the tailgating is occurring, but if the place where the vehicle stops is a no-parking zone, it is determined that the tailgating is occurring. Judgment device.

3. The determination device according to claim 1 or 2, The approach state determination unit is When the time during which the inter-vehicle distance between the first vehicle and the second vehicle is equal to or less than a predetermined threshold distance continues for a predetermined first threshold time or more, or when the number of times that the inter-vehicle distance is equal to or less than the threshold distance reaches a predetermined threshold number within a predetermined second threshold time, it is determined that the first vehicle and the second vehicle are in the approaching state. Judgment device.

4. The determination device according to any one of claims 1 to 3, The approach state determination unit is When the number of times that the second vehicle decelerates reaches a predetermined number within a predetermined time, it is determined that the second vehicle is in the approaching state. Judgment device.

5. The determination device according to claim 4, The approach state determination unit is The number of times the brake lamps of the second vehicle blink is obtained, and the obtained number of times the brake lamps blink is set as a number of times the second vehicle decelerates. Judgment device.

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