Inter-vehicle distance warning system, inter-vehicle distance warning device, and inter-vehicle distance warning method

Abstract

To provide an inter-vehicle distance warning system for preventing a detection omission of a preceding vehicle and further appropriately issuing a warning of an inter-vehicle distance.SOLUTION: An inter-vehicle distance warning system 10 includes: inter-vehicle distance warning devices installed in vehicles 20; and a server 100. The server 100 notifies a vehicle of an inter-vehicle distance warning notification when necessity of warning on an inter-vehicle distance is determined based on position information of a plurality of vehicles. The inter-vehicle distance warning device includes: an inter-vehicle distance warning acquisition section for acquiring the inter-vehicle distance warning notification; and a determination section information acquisition section for acquiring determination section information which indicates a determination state of an inter-vehicle distance by an on-vehicle machine. The inter-vehicle distance warning device includes: a warning state determination section for determining whether first processing to issue a warning on the inter-vehicle distance is being executed; and a determination state determination section for determining whether second processing to determine the inter-vehicle distance is being executed. The inter-vehicle distance warning device includes an inter-vehicle distance warning control section to which the inter-vehicle distance warning notification is transmitted and which controls issuing of the warning when neither the first processing nor the second processing are being executed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle distance warning system, a vehicle distance warning device, and a vehicle distance warning method. [Background technology]

[0002] Conventionally, devices have been proposed that judge the distance between vehicles and alert the driver by using a warning sound or the like when it is judged that the vehicle is too close to the vehicle ahead. Patent Document 1 discloses a vehicle distance warning device using a millimeter wave radar. The vehicle distance warning device disclosed in Patent Document 1 includes a rainfall amount detection means for detecting the amount of rainfall, and sets an upper limit for the warning generation speed according to the amount of rainfall, and issues a warning of the vehicle distance to the driver. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-230910 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle distance warning system using a millimeter wave radar, such as the vehicle distance warning device disclosed in Patent Document 1, the vehicle ahead may not be detected accurately depending on the surrounding environment, such as the state of shadows of objects, the accuracy of the radar distance, and the unevenness of the road surface. When the vehicle ahead cannot be detected accurately in this way, the vehicle distance warning is not issued appropriately, and there is a risk of getting too close to the vehicle ahead.

[0005] The present invention has been made in consideration of the problems inherent in the conventional technology, and an object of the present invention is to provide a vehicle distance warning system that can prevent a preceding vehicle from being overlooked and issue a vehicle distance warning more appropriately. [Means for solving the problem]

[0006] A vehicle distance warning system according to an aspect of the present invention is a vehicle distance warning system including a vehicle distance warning device provided in a vehicle, and a server, the server having a vehicle information acquisition unit that acquires vehicle information including vehicle position information from a plurality of vehicles, a surrounding vehicle determination unit that determines whether or not there is another vehicle around the vehicle based on the vehicle information, a vehicle distance warning determination unit that determines whether or not there is a need to issue a warning regarding the vehicle distance between the vehicle and the other vehicle when there is another vehicle around the vehicle, and a vehicle distance warning notification unit that transmits a vehicle distance warning notification to the vehicle when the vehicle distance warning determination unit determines that a warning is necessary, and the vehicle distance warning device transmits the vehicle distance warning notification sent from the server. The vehicle distance warning control unit includes a vehicle distance warning acquisition unit that acquires a vehicle distance warning notification, a judgment unit information acquisition unit that acquires judgment unit information indicating the judgment status of the vehicle distance by an onboard device installed in the vehicle, a warning status judgment unit that judges whether or not the judgment status of the vehicle is a first process that issues a vehicle distance warning based on the judgment unit information, a judgment status judgment unit that judges whether or not the judgment status of the vehicle is a second process that issues a vehicle distance judgment in the onboard device based on the judgment unit information, and a vehicle distance warning control unit that controls the onboard device to issue a warning when a vehicle distance warning notification is sent from the server and it is judged that the judgment status is not a first process that is being executed and not a second process that is being executed.

[0007] A vehicle distance warning device according to another aspect of the present invention includes a vehicle distance warning acquisition unit that acquires from the server a vehicle distance warning notification transmitted from a server, the vehicle distance between multiple vehicles being determined in the server based on vehicle information including position information acquired from the multiple vehicles, and when it is determined that a vehicle distance warning notification is necessary for the vehicle, the vehicle distance warning notification to be transmitted to the vehicle; a judgment unit information acquisition unit that acquires judgment unit information indicating a judgment status of the vehicle distance by an onboard device provided in the host vehicle; a warning status judgment unit that judges whether or not a first process for issuing a vehicle distance warning is being executed based on the judgment unit information; a judgment status judgment unit that judges whether or not a second process for issuing a vehicle distance warning is being executed in the onboard device based on the judgment unit information; and a vehicle distance warning control unit that controls the onboard device to issue a warning when a vehicle distance warning notification is transmitted from the server and it is determined that the judgment status is not that the first process is being executed and not that the second process is being executed.

[0008] A vehicle-to-vehicle distance warning method according to another aspect of the present invention is a vehicle-to-vehicle distance warning method executed by a computer, in which a vehicle-to-vehicle distance warning notification is sent from a server, in which the server determines the vehicle-to-vehicle distance between multiple vehicles based on vehicle information including position information acquired from the multiple vehicles, and when it is determined that a vehicle-to-vehicle distance warning notification is necessary, the server obtains the vehicle-to-vehicle distance warning notification to be sent to the vehicle from the server, obtains judgment unit information indicating the judgment status of the vehicle-to-vehicle distance by an onboard device installed in the vehicle, and determines based on the judgment unit information whether the judgment status of the vehicle is during the execution of a first process for issuing a vehicle-to-vehicle distance warning, and determines based on the judgment unit information whether the judgment status of the vehicle is during the execution of a second process for determining the vehicle-to-vehicle distance in the onboard device, and when a vehicle-to-vehicle distance warning notification is sent from the server and it is determined that the judgment status is not during the execution of the first process and not during the second process, controls the onboard device to issue a warning. Effect of the Invention

[0009] According to the present invention, it is possible to provide a vehicle distance warning system capable of preventing an oversight of detection of a preceding vehicle and more appropriately issuing a warning regarding the vehicle distance. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing a configuration of a vehicle distance warning system according to an embodiment of the present invention; [Diagram 2] 2 is a block diagram showing a configuration of an in-vehicle device according to the embodiment; FIG. [Diagram 3] FIG. 2 is a block diagram showing a configuration of a server according to the embodiment. [Figure 4] FIG. 2 is a block diagram showing a functional configuration of a server according to the present embodiment. [Diagram 5] 4 is a diagram for explaining data stored in a vehicle information DB according to the embodiment. FIG. [Figure 6] 1 is a block diagram showing a functional configuration of a vehicle distance warning device according to an embodiment of the present invention; [Figure 7A] 11 is a diagram showing an example of data stored in a determination unit information DB according to the embodiment. FIG. [Figure 7B] 11 is a diagram showing an example of data stored in a determination unit information DB according to the embodiment. FIG. [Figure 7C] 11 is a diagram showing an example of data stored in a determination unit information DB according to the embodiment. FIG. [Figure 8] 10 is a flowchart illustrating an example of a process of a server according to the embodiment. [Figure 9] 5 is a flowchart showing an example of a process of a vehicle distance warning determination unit according to the embodiment. [Figure 10] 5 is a flowchart showing an example of a process of a vehicle distance warning determination unit according to the embodiment. [Figure 11] 4 is a flowchart showing an example of a process of the following distance warning device according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The vehicle distance warning system 10 and the vehicle distance warning device 201 according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios of the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios. In addition, in the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0012] (Configuration of Inter-Vehicle Distance Warning System 10) 1 is a diagram showing the configuration of a vehicle distance warning system 10 according to this embodiment. As shown in FIG. 1, the vehicle distance warning system 10 includes a server 100 and an on-board device 200 mounted on a vehicle 20.

[0013] The vehicle distance warning system 10 issues a vehicle distance warning in response to a notification from the server 100, in addition to the vehicle distance warning issued by the vehicle 20. The vehicle-mounted device 200 is also provided with a vehicle distance warning device 201, which will be described later, and controls the issuing of the vehicle distance warning.

[0014] For example, in a typical distance warning using a millimeter wave radar, the preceding vehicle may not be detected accurately due to the surrounding environment such as the state of shadows of objects, the accuracy of the radar distance, the unevenness of the road surface, etc. When the preceding vehicle cannot be detected accurately in this way, the distance warning may not be issued appropriately, and there is a risk of getting too close to the preceding vehicle.

[0015] In the following distance warning system 10 according to this embodiment, in addition to the vehicle-mounted device 200 determining the vehicle distance using a millimeter wave radar or the like, the vehicle distance warning is issued based on a vehicle distance warning notification sent from the server 100. As a result, the vehicle distance warning system 10 according to this embodiment realizes a system that prevents the failure to detect a preceding vehicle and can more appropriately issue a vehicle distance warning.

[0016] (Configuration of the vehicle-mounted device 200) Fig. 2 is a block diagram showing a configuration of an on-vehicle device 200 including a vehicle distance warning device 201. As shown in Fig. 2, the on-vehicle device 200 includes a control unit 210. The on-vehicle device 200 also includes a speed signal IF231, an engine signal IF232, a GPS IF233 (Global Positioning System), an external input / output IF234, and a sensor signal IF235.

[0017] The vehicle-mounted device 200 also includes a vehicle-to-vehicle warning determination unit 236 that determines the vehicle-to-vehicle distance based on information acquired via each IF of the vehicle-mounted device 200 .

[0018] Furthermore, the vehicle-mounted device 200 includes a wide-area communication module 241, a non-volatile memory 242, a volatile memory 243, an SD card 244, a SW input unit 245, and an LCD (Liquid Crystal Display) 246. The non-volatile memory 242, the volatile memory 243, and the SD card 244 correspond to the storage unit 220 of the vehicle-mounted device 200.

[0019] The control unit 210 executes a pre-installed program to realize various functions required for the vehicle-mounted device 200. The main operations of the control unit 210 will be described later.

[0020] The speed signal IF 231 converts a predetermined vehicle speed signal output from the vehicle side into a signal suitable for input processing by the control unit 210. The control unit 210 can grasp the traveling speed and traveling distance of the vehicle 20 by monitoring the number of pulses of the vehicle speed signal and the signal period.

[0021] The engine signal IF 232 converts a predetermined engine rotation signal output from the vehicle side into a signal suitable for input processing by the control unit 210. The control unit 210 can grasp the engine rotation speed (rpm) by monitoring the number of pulses and the signal period of the engine rotation signal.

[0022] The GPSIF 233 is used to input a signal from a GPS receiver (not shown) to the control unit 210. The GPS receiver receives radio waves from a plurality of GPS satellites and can calculate the current position of the vehicle 20, which is the reception point. The control unit 210 can obtain information on the current position from the GPS receiver via the GPSIF 233.

[0023] The external input / output IF 234 converts a predetermined external signal into a signal suitable for input processing of the control unit 210. In addition, the external input / output IF 234 outputs the predetermined signal to the outside. For example, the external input / output IF 234 outputs an alarm sound via a speaker (not shown).

[0024] The sensor signal IF 235 is used to input information acquired by sensors provided in the vehicle 20, such as a vehicle distance measurement sensor, an angular velocity sensor, a weight sensor, a temperature sensor, etc., to the control unit 210. The vehicle distance measurement sensor (not shown) may be a sensor that measures the vehicle distance based on data acquired by a camera or a radar.

[0025] The vehicle distance warning determination unit 236 determines the distance between the vehicle and the preceding vehicle acquired via the vehicle distance measurement sensor and the sensor signal IF 235, and when the vehicle distance is shorter than a predetermined distance, issues an alarm sound via the external input / output IF 234 and a speaker (not shown). The vehicle distance warning determination unit 236 may also issue an alarm to a car navigation system or the like via an LCD 246 described later.

[0026] For example, when the speed of the host vehicle is between 20km / h and 80km / h and the time interval between the host vehicle and the preceding vehicle is less than 2.5 seconds, the vehicle distance warning determination unit 236 determines that a warning is necessary. Also, when the speed of the host vehicle is between 1 and 30km / h and the distance between the host vehicle and the preceding vehicle is between 1 and 10m, the vehicle distance warning determination unit 236 determines that a warning is necessary.

[0027] The determination by the vehicle distance warning determination unit 236 as to whether or not a warning is necessary according to the vehicle distance is not limited to the above values, and a warning may be necessary according to settings even in situations other than the above values.

[0028] In this manner, the vehicle distance warning determination unit 236 according to this embodiment issues a general vehicle distance warning in accordance with the vehicle distance to the preceding vehicle.

[0029] The wide-area communication module 241 has a function for securing a wireless communication line with, for example, a wireless base station (not shown) provided by a mobile communication carrier, etc., and enabling wide-area wireless communication. In this embodiment, the wide-area communication module 241 may also have a function for enabling short-distance wireless communication from a communication device provided on a traffic light or the like located nearby.

[0030] The non-volatile memory 242 is an electronic device such as a flash memory that can read data and rewrite the stored data by accessing the control unit 210. The non-volatile memory 242 is used to store data such as various parameters, constant data, programs, etc. used by the in-vehicle device 200.

[0031] The volatile memory 243 is a semiconductor memory device from which data can be read and written by access from the control unit 210. The volatile memory 243 is used to temporarily store various data handled by the control unit 210.

[0032] The SD card 244 is detachably connected to the vehicle-mounted device 200 using a predetermined card interface (not shown). The SD card 244 is used to store various data to be recorded by the vehicle-mounted device 200, such as operation data of the vehicle 20.

[0033] The SW input unit 245 includes switches that generate signals representing the operation states of a plurality of buttons for receiving input operations by the driver of the vehicle 20. For example, switch signals acquired by the SW input unit 245 include an ON / OFF signal of an ignition SW (not shown), an ON / OFF signal of a brake SW (not shown), an ON / OFF signal of a turn signal SW (not shown), and the like.

[0034] The LCD 246 is disposed at a position on the front side of the housing of the in-vehicle device 200 that is easily visible to the driver, and is used, for example, to display the operating state of the in-vehicle device 200 under the control of the control unit 210. The LCD 246 may also have a function of displaying a vehicle distance warning.

[0035] (Server 100 Configuration) 3 is a block diagram showing the configuration of the server 100. In this embodiment, the server 100 is configured by a general computer including a control unit 110, a storage unit 120, an input / output IF 130 (Interface), and a communication IF 140. Details of the control unit 110 and the storage unit 120 will be described later.

[0036] The input / output IF 130 is, for example, a component (interface) for a user to exchange data with the server 100. The input / output IF 130 includes, for example, an input IF and an output IF (not shown).

[0037] The input IF in the input / output IF 130 has an interface function for inputting various information by the user, and information is input from outside the server 100. The user inputs information to the input IF through, for example, a keyboard, a mouse, a touch panel, a trackball, a voice recognition device, or the like, connected to the server 100. The input IF can also input information as a data input terminal for inputting data from an external storage device (not shown) or the like.

[0038] The output IF in the input / output IF 130 can display the shipper destination information and operation information described below on a display device (not shown) connected to the server 100. The display device is, for example, a display device, a projector device, or the like.

[0039] The communication IF 140 is an interface for enabling mutual communication between the server 100 and the on-board device 200 of the vehicle 20 via the network 40.

[0040] (Functional configuration of server 100) Fig. 4 is a block diagram showing the functional configuration of the server 100 according to this embodiment. As shown in Fig. 4, the control unit 110 of the server 100 includes a vehicle information acquisition unit 111, a surrounding vehicle determination unit 112, a vehicle distance warning determination unit 113, and a vehicle distance warning notification unit 114 as functions.

[0041] Furthermore, the control unit 110 operates, for example, an operating system to control the entire server 100. Furthermore, the control unit 110 operates based on a program stored in the storage unit 120 to execute each of the above-mentioned functions. Note that the program is not limited to being stored in the storage unit 120, and may be stored, for example, in a ROM (Read Only Memory) or the like (not shown) in the server 100.

[0042] As shown in Fig. 4, the storage unit 120 stores information included in a vehicle information DB 121 (DB: Database) as data. The number of storage units 120 that store each of these data may be one or more. For example, a single storage unit 120 may be configured to store the data in separate areas. Alternatively, the data may be distributed and stored in a plurality of storage devices that are installed in physically separate locations.

[0043] Fig. 5 is a diagram for explaining data stored in the vehicle information DB 121 according to this embodiment. As shown in Fig. 5, the vehicle information DB 121 stores "vehicle ID" which is identification information for identifying the multiple vehicles 20, and information related to "vehicle position", "traveling direction", and "speed" acquired from the multiple vehicles 20. Note that the data stored in the vehicle information DB 121 is not limited to the items shown in Fig. 5, and may store vehicle model indicating the type of vehicle 20, acceleration related to the running of the vehicle 20, engine speed, etc.

[0044] Next, the functional configuration of the server 100 shown in FIG. 4 will be described in detail.

[0045] The vehicle information acquisition unit 111 acquires vehicle information including position information of the vehicles 20 from a plurality of vehicles 20. The vehicle information acquisition unit 111 stores the acquired vehicle information in the vehicle information DB 121. In this embodiment, the vehicle information includes, in addition to the position information of the vehicles 20, traveling direction information of the vehicles 20 and speed information related to the speed of the vehicles 20.

[0046] The surrounding vehicle determination unit 112 determines whether or not other vehicles 20 exist around the vehicle 20, based on the vehicle information of a plurality of vehicles 20. Specifically, the surrounding vehicle determination unit 112 determines whether or not other vehicles 20 exist around the vehicle 20, based on the position information of the vehicle information.

[0047] When another vehicle 20 is present around the vehicle 20, the vehicle distance warning determination unit 113 determines whether or not it is necessary to issue a warning based on the vehicle distance between the vehicle 20 and the other vehicle 20. The vehicle distance warning determination unit 113 determines the vehicle distance between the host vehicle and the other vehicle 20 traveling in the same direction ahead of the host vehicle. That is, the vehicle distance warning determination unit 113 determines that a warning is necessary when the traveling directions indicated in the traveling direction information of the multiple vehicles 20 are the same direction and the vehicle distance between the vehicle 20 and the other vehicle 20 is shorter than a predetermined distance.

[0048] For example, like the vehicle distance warning determination unit 236 mounted on the above-mentioned vehicle-mounted device 200, the vehicle distance warning determination unit 113 determines that a warning is necessary when the speed of the target vehicle 20 is 20 km / h to 80 km / h and the time between the target vehicle and the preceding vehicle becomes 2.5 seconds or less. The vehicle distance warning determination unit 113 also determines that a warning is necessary when the speed of the target vehicle 20 is 1 to 30 km / h and the distance between the target vehicle and the preceding vehicle approaches 1 to 10 m.

[0049] The determination by the vehicle distance warning determination unit 113 as to whether or not a warning is necessary according to the vehicle distance is not limited to the above values, and a warning may be necessary according to settings even in situations other than the above values.

[0050] When the vehicle distance warning determination unit 113 determines that a warning is necessary, the vehicle distance warning notification unit 114 transmits a vehicle distance warning notification to the vehicle 20. In this embodiment, the vehicle distance warning notification is information indicating that a warning is necessary in the vehicle 20.

[0051] (Functional configuration of the vehicle distance warning device 201) Next, functions of the following distance warning device 201 according to this embodiment provided in the on-board device 200 of the vehicle 20 will be described with reference to Fig. 6. Fig. 6 is a block diagram showing the functional configuration of the following distance warning device 201 according to this embodiment. As shown in Fig. 6, the control unit 210 of the following distance warning device 201 includes, as functions, a following distance warning acquisition unit 211, a judgment unit information acquisition unit 212, a warning status judgment unit 213, a judgment status judgment unit 214, and a following distance warning control unit 215.

[0052] The control unit 210 also operates, for example, an operating system to control the entire vehicle-mounted device 200. Furthermore, the control unit 210 operates based on a program stored in the storage unit 220 to execute each of the above-mentioned functions.

[0053] 6, the storage unit 220 stores information included in a vehicle distance warning information DB 221 (DB: Database) and a determination unit information DB 222 as data. The number of storage units 220 that store these pieces of data may be one or more. For example, a single storage unit 220 may be configured to store the data in separate areas. Alternatively, the storage unit 220 may store data in a distributed manner in multiple storage devices installed in physically separate locations, such as a non-volatile memory 242, a volatile memory 243, and / or an SD card 244.

[0054] In the case where a following distance warning notification is transmitted from the server 100, the following distance warning information DB 221 stores the following distance warning notification. Here, the following distance warning notification is information indicating that a warning is required from the target vehicle 20, and is information originating from the server 100. For example, the following distance warning information DB 221 may indicate the following distance warning notification by storing information indicating whether or not a following distance warning notification has been received from the server 100.

[0055] The determination unit information DB 222 stores, as determination unit information, the operating status of the vehicle-to-vehicle distance warning determination unit 236 of the vehicle-mounted device 200 shown in Fig. 2. Fig. 7A, Fig. 7B, and Fig. 7C show examples in which data corresponding to the operating status of the vehicle-to-vehicle distance warning determination unit 236 is stored.

[0056] As shown in the flowchart of Fig. 10, the vehicle distance warning determination unit 236 performs vehicle distance determination based on information acquired via the sensor signal IF 235, and instructs the in-vehicle device 200 to perform a vehicle distance warning if a vehicle distance warning is necessary. Here, in this specification, the process of vehicle distance determination is defined as Phase 1, the process of vehicle distance warning is defined as Phase 2, and the case where it is determined that a vehicle distance warning is not to be performed is defined as Phase 3. The details of the flowchart shown in Fig. 10 will be described later. Phase 1, in which the process of vehicle distance determination is performed, corresponds to the second process. Phase 2, in which the process of vehicle distance warning is performed, corresponds to the first process.

[0057] Returning to the description of the determination unit information DB 222 shown in Figures 7A to 7C, Figure 7A shows an example where the operation status of the distance warning determination unit 236 is in Phase 1 shown in Figure 10, i.e., where processing for determining the distance between vehicles is being performed. Figure 7B shows an example where the operation status of the distance warning determination unit 236 is in Phase 2 shown in Figure 10, i.e., where processing for the distance warning is being performed. Figure 7C shows an example where the operation status of the distance warning determination unit 236 is in Phase 3 shown in Figure 10, i.e., where it is determined that no distance warning should be issued.

[0058] 7A to 7C, information indicating the presence or absence of a following distance warning notification from the server 100 and information indicating whether or not to perform warning control on the following distance warning control unit 215 are stored. Figs. 7A and 7B show an example in which warning control is not performed on the following distance warning control unit 215, and Fig. 7C shows an example in which warning control is performed on the following distance warning control unit 215. Also, all of the examples shown in Figs. 7A to 7C show an example in which a following distance warning notification is received from the server 100.

[0059] Next, the functional configuration of the following distance warning device 201 shown in FIG. 6 will be described in detail.

[0060] The following distance warning acquisition unit 211 acquires a following distance warning notification transmitted from the server 100. The following distance warning acquisition unit 211 also stores information related to the following distance warning notification transmitted from the server 100 in the following distance warning information DB 221. When there is a following distance warning notification from the server 100, the following distance warning information DB 221 stores information indicating that the following distance warning notification has been stored. For example, in the example shown in Figs. 7A to 7C, when there is a following distance warning notification from the server 100, information indicating "Yes" is stored in the following distance warning item.

[0061] The determination unit information acquisition unit 212 acquires determination unit information indicating a determination status of the inter-vehicle distance by the in-vehicle device 200 provided in the vehicle itself. Specifically, the determination unit information acquisition unit 212 acquires determination information indicating a determination status of the inter-vehicle distance warning determination unit 236 provided in the in-vehicle device 200 from the inter-vehicle distance warning determination unit 236. In addition, the determination unit information acquisition unit 212 stores the acquired determination information in the determination unit information DB 222. The determination information stored in the determination unit information DB 222 is, for example, information as shown in Figs. 7A to 7C.

[0062] The warning status determination unit 213 determines whether the determination status of the host vehicle is in the process of issuing a vehicle distance warning (second phase) based on the determination unit information. The second phase processing corresponds to the first processing. The processing time of this phase 2 is, for example, 3 s (seconds). That is, the vehicle-mounted device 200 issues a vehicle distance warning in about 3 s (seconds). In this embodiment, the processing time of phase 2, which is the time for issuing the vehicle distance warning, is not limited to 3 s (seconds) and may be longer or shorter than 3 seconds.

[0063] The judgment status judgment unit 214 judges, based on the judgment unit information, whether the judgment status of the host vehicle is that the process (first phase) for judging the inter-vehicle distance is being executed in the in-vehicle device 200. The process of the first phase corresponds to the second process. The processing time of this phase 1 is, for example, 100 ms (milliseconds). That is, the in-vehicle device 200 judges the inter-vehicle distance every 100 ms (milliseconds). In this embodiment, the processing time for judging the inter-vehicle distance is not limited to 100 ms (milliseconds), and may be longer or shorter than 100 ms (milliseconds).

[0064] When a vehicle-to-vehicle distance warning notification is transmitted from the server 100, the vehicle-mounted device 200 controls (instructs) to issue a warning in a predetermined case. Here, the predetermined case is when the warning status determination unit 213 determines that the determination status is not the second phase being executed and not the first phase being executed. The processing of the second phase corresponds to the first processing. The processing of the first phase corresponds to the second processing.

[0065] For example, in the second phase processing, a warning of the inter-vehicle distance is issued by the inter-vehicle warning determination unit 236. In the first phase processing, the inter-vehicle distance is determined by the inter-vehicle warning determination unit 236, and if a warning is necessary according to the result of the determination, a warning is issued.

[0066] In the following distance warning system 10, when the determination state is not in the second phase and not in the first phase, i.e., in the third phase, an alarm is issued under the control of the following distance warning control unit 215 in response to a following distance warning notification from the server 100. That is, in the following distance warning system 10 according to this embodiment, in addition to issuing an alarm normally by the following distance warning determination unit 236, an alarm is also issued when the following distance warning determination unit 236 fails to issue an alarm, such as when the following distance warning determination unit 236 fails to issue an alarm. This enables the following distance warning system 10 to prevent an alarm from being issued without warning and to prevent an unnecessary alarm from being issued, thereby more appropriately issuing an alarm for the following distance.

[0067] Furthermore, the vehicle-mounted device 200 that is controlled (instructed) to issue a warning by the following distance warning control unit 215 generates a warning sound via the external input / output IF 234. Furthermore, the vehicle-mounted device 200 may cause a car navigation system or the like to display a warning of the following distance via the LCD 246.

[0068] (Outline of the process flow of the vehicle distance warning system 10) Next, the flow of processing in the following distance warning system 10 will be shown using the flowcharts shown in Figures 8 to 11. A series of operations of the following distance warning system 10 shown in the flowcharts of Figures 8 to 11 starts when the following distance warning system 10 is started, and ends when the operation is completed. The processing in the flowcharts shown in Figures 8 to 11 also ends when the server 100 or the vehicle-mounted device 200 is powered off or an interrupt occurs to end the processing. In the following explanation of the flowcharts, the same contents as those described in the above explanation of the following following distance warning system 10 will be omitted or simplified.

[0069] Fig. 8 is a flowchart showing an example of the processing of the server 100. Figs. 9 and 10 are flowcharts showing an example of the processing of the vehicle-to-vehicle distance warning determination unit 236 provided in the vehicle-mounted device 200. Furthermore, Fig. 11 is a flowchart showing an example of the processing of the vehicle-to-vehicle distance warning device 201. First, the flowchart showing an example of the processing of the server 100 shown in Fig. 8 will be described.

[0070] 8, the vehicle information acquisition unit 111 acquires vehicle information including position information of the vehicles 20 from a plurality of vehicles 20. The vehicle information acquisition unit 111 also stores the acquired vehicle information in the vehicle information DB 121. In this embodiment, the vehicle information includes, in addition to the position information of the vehicles 20, traveling direction information of the vehicles 20 and speed information related to the speed of the vehicles 20. Thereafter, the process proceeds to step S802.

[0071] In step S802, the surrounding vehicle determination unit 112 determines whether or not other vehicles 20 exist around the vehicle 20 based on the vehicle information of the multiple vehicles 20. Specifically, the surrounding vehicle determination unit 112 determines whether or not other vehicles 20 exist around the vehicle 20 based on the position information of the vehicle information. In step S802, if the surrounding vehicle determination unit 112 determines that other vehicles 20 exist around the vehicle 20 (step S802: YES), the process proceeds to step S803. On the other hand, in step S802, if the surrounding vehicle determination unit 112 determines that other vehicles 20 do not exist around the vehicle 20 (step S802: NO), the process proceeds to step S805.

[0072] In step S803, when another vehicle 20 is present around the vehicle 20, the vehicle distance warning determination unit 113 determines whether or not it is necessary to issue a warning based on the vehicle distance between the vehicle 20 and the other vehicle 20. The vehicle distance warning determination unit 113 determines the vehicle distance between the host vehicle and the other vehicle 20 traveling in the same traveling direction ahead of the host vehicle. For example, when the speed of the host vehicle is between 20 km / h and 80 km / h, it determines that a warning is necessary when the time between the host vehicle and the preceding vehicle becomes 2.5 seconds or less. It also determines that a warning is necessary when the speed of the host vehicle is between 1 and 30 km / h and the distance between the host vehicle and the preceding vehicle becomes 1 to 10 m.

[0073] In step S803, if the following distance warning determination unit 113 determines that a following distance warning notification is necessary (step S803: YES), the process proceeds to step S804. On the other hand, in step S803, if the following distance warning determination unit 113 determines that a following distance warning notification is not necessary (step S803: NO), the process proceeds to step S805.

[0074] In step S804, when the distance warning determination unit 113 determines that a warning is necessary, the distance warning notification unit 114 transmits a distance warning notification to the vehicle 20. In this embodiment, the distance warning notification is information indicating that a warning is necessary in the vehicle 20. Then, the process proceeds to step S805.

[0075] In step S805, the control unit 110 determines whether the process is to end. In this embodiment, the process is ended when, for example, the server 100 is turned off or all of the vehicles 20 that are the subject of the following distance warning have finished traveling. The process of ending is also included when the user controls the server 100 to end via the input / output IF 130.

[0076] If control unit 110 determines in step S805 that the processing is to end (step S805: YES), the processing of control unit 110 in server 100 ends. On the other hand, if control unit 110 determines in step S805 that the processing is not to end (step S805: NO), the processing returns to step S801, and the processing from step S801 is repeatedly performed.

[0077] Next, a description will be given of a flowchart showing an example of the process of the vehicle-to-vehicle warning determination unit 236 provided in the vehicle-mounted device 200 shown in Fig. 9 and Fig. 10. The process of the vehicle-to-vehicle warning determination unit 236 shown in Fig. 9 and Fig. 10 corresponds to a normal process of determining the vehicle distance and issuing a warning.

[0078] In step S901, the vehicle distance warning determination unit 236 performs an in-vehicle device determination process. The process in step S901 is a subroutine process shown in Fig. 10. The details of the subroutine process shown in Fig. 10 will be described later. After that, the process proceeds to step S902.

[0079] In step S902, the vehicle distance warning determination unit 236 determines whether or not the vehicle 20 has stopped traveling. If the vehicle distance warning determination unit 236 determines in step S902 that the vehicle 20 has stopped traveling (step S902: YES), the process ends. On the other hand, if the vehicle distance warning determination unit 236 determines in step S902 that the vehicle 20 has not stopped traveling (step S902: NO), the process returns to step S901, and the process of step S901 is repeatedly performed.

[0080] Next, a subroutine process of the vehicle-mounted device determination process in the vehicle-to-vehicle warning determination unit 236 will be described. In step S1001 in Fig. 10, the vehicle-to-vehicle warning determination unit 236 performs a vehicle distance determination. For example, the vehicle-to-vehicle warning determination unit 236 performs the determination based on a signal of a vehicle-to-vehicle distance measurement sensor acquired via the sensor signal IF 235. Thereafter, the process proceeds to step S1002.

[0081] In step S1002, the vehicle-to-vehicle distance warning determination unit 236 determines whether or not a vehicle-to-vehicle distance warning is necessary based on the determination result in step S1001. If the vehicle-to-vehicle distance warning determination unit 236 determines in step S1002 that a vehicle-to-vehicle distance warning is necessary (step S1002: YES), the process proceeds to step S1003. On the other hand, if the vehicle-to-vehicle distance warning determination unit 236 determines in step S1002 that a vehicle-to-vehicle distance warning is not necessary (step S1002: NO), the process returns to step S901 in the flowchart of FIG. 9 (RETURN).

[0082] In step S1003, the vehicle-to-vehicle distance warning determination unit 236 issues a vehicle-to-vehicle distance warning. Specifically, the vehicle-to-vehicle distance warning determination unit 236 issues a warning sound from a speaker via the in-vehicle device 200 and the external input / output IF 234. The vehicle-to-vehicle distance warning determination unit 236 may also display a warning on a display device such as a car navigation system via the in-vehicle device 200 and the LCD 246. Thereafter, the process returns to step S901 in the flowchart of FIG. 9 (RETURN).

[0083] Next, a description will be given of a flowchart showing an example of the processing of the following distance warning device 201 shown in Fig. 11. In the processing of the following distance warning device 201 shown in Fig. 11, in addition to the normal warning issued by the following distance warning determination unit 236 shown in Figs. 9 and 10 described above, a warning is issued in response to a following distance warning notification from the server 100.

[0084] In step S1101, the following distance warning acquisition unit 211 determines whether or not there is a following distance warning notification from the server 100. In step S1101, if the following distance warning acquisition unit 211 determines that there is a following distance warning notification from the server 100 (step S1101: YES), it acquires the following distance warning notification and stores the acquired following distance warning notification in the following distance warning information DB 221. Thereafter, the process proceeds to step S1102. On the other hand, in step S1101, if the following distance warning acquisition unit 211 determines that there is no following distance warning notification from the server 100 (step S1101: NO), the process returns to step S1101, and the process from step S1101 is repeatedly performed.

[0085] In this embodiment, the determination by the following distance warning acquisition unit 211 in step S1101 is performed at intervals of, for example, 100 ms. The intervals of the determination by the following distance warning acquisition unit 211 do not limit the configuration of the embodiment, and may be longer or shorter than 100 ms, for example.

[0086] In step S1102, the determination unit information acquisition unit 212 acquires determination unit information indicating the determination status of the inter-vehicle distance by the in-vehicle device 200 provided in the vehicle itself. Specifically, the determination unit information acquisition unit 212 acquires determination information indicating the determination status of the inter-vehicle distance warning determination unit 236 provided in the in-vehicle device 200 from the inter-vehicle distance warning determination unit 236. The determination unit information acquisition unit 212 also stores the acquired determination information in the determination unit information DB 222. The determination information stored in the determination unit information DB 222 is, for example, information as shown in Figs. 7A to 7C. Thereafter, the process proceeds to step S1103.

[0087] In step S1103, the warning status determination unit 213 determines whether the determination status of the host vehicle is in the process of issuing a vehicle distance warning (second phase) based on the determination unit information. The second phase processing corresponds to the first processing. The processing time of this phase 2 is, for example, 3 s (seconds). That is, the vehicle-mounted device 200 issues a vehicle distance warning in about 3 s (seconds). In this embodiment, the processing time of phase 2, which is the time for issuing the vehicle distance warning, is not limited to 3 s (seconds), and may be longer or shorter than 3 seconds.

[0088] In step S1103, if the warning status determination unit 213 determines based on the determination unit information that the determination status of the host vehicle is that the process (second phase) for issuing a vehicle distance warning is in progress (step S1103: YES), the process proceeds to step S1106. On the other hand, in step S1103, if the warning status determination unit 213 determines based on the determination unit information that the determination status of the host vehicle is not that the process (second phase) for issuing a vehicle distance warning is in progress (step S1103: NO), the process proceeds to step S1104.

[0089] In step S1104, the judgment status judgment unit 214 judges whether the judgment status of the host vehicle is that the process (first phase) for judging the inter-vehicle distance is being executed in the in-vehicle device 200. The process of the first phase corresponds to the second process. The processing time of this phase 1 is, for example, 100 ms (milliseconds). That is, the in-vehicle device 200 judges the inter-vehicle distance every 100 ms (milliseconds). In this embodiment, the processing time for judging the inter-vehicle distance is not limited to 100 ms (milliseconds), and may be longer or shorter than 100 ms (milliseconds). After that, the process proceeds to step S1105.

[0090] In step S1104, if the determination status determination unit 214 determines that the determination status of the host vehicle is that the process (first phase) of determining the inter-vehicle distance is being executed in the in-vehicle device 200 (step S1104: YES), the process proceeds to step S1106. On the other hand, in step S1104, if the determination status determination unit 214 determines that the determination status of the host vehicle is not that the process (first phase) of determining the inter-vehicle distance is being executed in the in-vehicle device 200 (step S1104: NO), the process proceeds to step S1105.

[0091] In step S1105, the following distance warning control unit 215 controls (instructs) the in-vehicle device 200 to issue a warning. The in-vehicle device 200 controlled (instructed) to issue a warning by the following distance warning control unit 215 generates a warning sound via the external input / output IF 234. The in-vehicle device 200 may also cause a car navigation system or the like to display a warning of the following distance via the LCD 246. After that, the process proceeds to step S1106.

[0092] As described above, in the following distance warning system 10 according to this embodiment, the vehicle-to-vehicle warning determination unit 236 issues a warning in the first and second phases of Fig. 10, and issues a warning in the remaining third phase. That is, in the following distance warning system 10, in addition to issuing a normal warning by the vehicle-to-vehicle warning determination unit 236, an alarm is issued even when the vehicle-to-vehicle warning determination unit 236 does not issue a warning, such as when the vehicle-to-vehicle warning determination unit 236 fails to issue a warning. This enables the vehicle-to-vehicle distance warning system 10 to prevent a warning from being issued and to prevent unnecessary warnings from being issued, thereby more appropriately issuing a warning for the following distance.

[0093] In step S1106, the control unit 210 determines whether or not the traveling of the vehicle 20 has ended. If the control unit 210 determines in step S1106 that the traveling of the vehicle 20 has ended (step S1106: YES), the process ends. On the other hand, if the control unit 210 determines in step S1106 that the traveling of the vehicle 20 has not ended (step S1106: NO), the process returns to step S1101, and the process from step S1101 is repeatedly performed.

[0094] As described above, the following distance warning system 10 according to the present embodiment is configured to include a following distance warning device 201 provided in the vehicle 20 and a server 100. The server 100 has a vehicle information acquisition unit 111 that acquires vehicle information including the position information of the vehicle 20 from a plurality of vehicles 20. The server 100 also has a surrounding vehicle determination unit 112 that determines whether or not another vehicle 20 exists around the vehicle 20 based on the vehicle information. The server 100 also has a following distance warning determination unit 113 that determines whether or not an alarm is required for the following distance between the vehicle 20 and the other vehicle 20 when the other vehicle 20 exists around the vehicle 20. The server 100 also has a following distance warning notification unit 114 that transmits a following distance warning notification to the vehicle 20 when the following distance warning determination unit 113 determines that an alarm is required. The following distance warning device 201 has a following distance warning acquisition unit 211 that acquires a following distance warning notification transmitted from the server 100, and a judgment unit information acquisition unit 212 that acquires judgment unit information indicating a judgment status of the following distance by the in-vehicle device 200 provided in the vehicle. The following distance warning device 201 also has a warning status judgment unit 213 that judges whether or not the judgment status of the vehicle is a first process for issuing a following distance warning based on the judgment unit information. The following distance warning device 201 also has a judgment status judgment unit 214 that judges whether or not the judgment status of the vehicle is a second process for judging the following distance in the in-vehicle device 200 based on the judgment unit information. The following distance warning device 201 also has a following distance warning control unit 215. The vehicle-to-vehicle distance warning control unit 215 controls the vehicle-mounted device 200 to issue a warning when a vehicle-to-vehicle distance warning notification is transmitted from the server 100 and it is determined that the first process is not being executed and that the second process is not being executed. The first process corresponds to the second phase. The second process corresponds to the first phase.

[0095] As a result, the determination of the distance by the following distance warning system 10 reflects the result of the following distance determination performed by the server 100 in addition to the following distance determination performed by the vehicle 20. Therefore, the following distance warning system 10 can prevent the preceding vehicle from being overlooked and issue a more appropriate following distance warning.

[0096] The vehicle information may also include travel direction information and speed information of the vehicle 20. Furthermore, the following distance warning determination unit 113 may determine the following distance based on the position information, travel direction information, and speed information of the vehicle 20 included in the vehicle information. This enables the following distance warning system 10 to more accurately determine the following distance of the vehicle 20 in the server 100.

[0097] Furthermore, the vehicle distance warning determination unit 113 may determine that a warning is necessary when the traveling directions indicated in the traveling direction information of the multiple vehicles 20 are the same direction and the vehicle distance between the vehicle 20 and another vehicle 20 is shorter than a predetermined distance. This allows the vehicle distance warning system 10 to reduce erroneous determination of the vehicle distance in the server 100 and more accurately determine the vehicle distance between the vehicles 20.

[0098] (Other embodiments) Although the embodiments have been described in detail with reference to the drawings, the present embodiments are not limited to the contents described in the above embodiments. The components described above include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described above can be appropriately combined. Various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the embodiments.

[0099] Furthermore, a computer program (vehicle distance warning program) that causes a computer to execute the processing (vehicle distance warning method) in the above-mentioned vehicle distance warning device 201, and a computer-readable recording medium on which the program is recorded, are included in the scope of this embodiment. Any type of computer-readable recording medium may be used. Furthermore, the computer program is not limited to one recorded on the above-mentioned recording medium, and may be one transmitted via an electric communication line, a wireless or wired communication line, a network such as the Internet, or the like.

[0100] The following describes the features of the following distance warning system 10, the following distance warning device 201, and the following distance warning method.

[0101] The following distance warning system 10 according to the first embodiment is a following distance warning system 10 including a following distance warning device 201 provided in a vehicle 20 and a server 100. The server 100 has a vehicle information acquisition unit 111 that acquires vehicle information including the position information of the vehicle 20 from a plurality of vehicles 20. The server 100 also has a surrounding vehicle determination unit 112 that determines whether or not another vehicle 20 exists around the vehicle 20 based on the vehicle information. The server 100 also has a following distance warning determination unit 113 that determines whether or not an alarm is required for the following distance between the vehicle 20 and the other vehicle 20 when the other vehicle 20 exists around the vehicle 20. The server 100 also has a following distance warning notification unit 114 that transmits a following distance warning notification to the vehicle 20 when the following distance warning determination unit 113 determines that an alarm is required. The following distance warning device 201 has a following distance warning acquisition unit 211 that acquires a following distance warning notification transmitted from the server 100, and a judgment unit information acquisition unit 212 that acquires judgment unit information indicating a judgment status of the following distance by the in-vehicle device 200 provided in the vehicle. The following distance warning device 201 also has a warning status judgment unit 213 that judges whether or not the judgment status of the vehicle is a first process for issuing a following distance warning based on the judgment unit information. The following distance warning device 201 also has a judgment status judgment unit 214 that judges whether or not the judgment status of the vehicle is a second process for judging the following distance in the in-vehicle device 200 based on the judgment unit information. The following distance warning device 201 also has a following distance warning control unit 215. The vehicle-to-vehicle distance warning control unit 215 controls the vehicle-mounted device 200 to issue a warning when a vehicle-to-vehicle distance warning notification is transmitted from the server 100 and it is determined that the first process is not being executed and that the second process is not being executed. The first process corresponds to the second phase. The second process corresponds to the first phase.

[0102] According to the above configuration, the following distance determination by the following distance warning system 10 reflects the result of the following distance determination performed by the server 100 in addition to the following distance determination by the vehicle 20. Therefore, the following distance warning system 10 can prevent the preceding vehicle from being overlooked and issue a following distance warning more appropriately.

[0103] The vehicle information of the following distance warning system 10 according to the second embodiment may include traveling direction information and speed information of the vehicle 20. Furthermore, the following distance warning determination unit 113 may determine the following distance based on the position information, traveling direction information, and speed information of the vehicle 20 included in the vehicle information.

[0104] According to the above configuration, the following distance warning system 10 can determine the following distance of the vehicle 20 more accurately in the server 100.

[0105] The vehicle distance warning determination unit 113 according to the third aspect may determine that a warning is necessary when the travel directions indicated in the travel direction information of multiple vehicles 20 are the same direction and the vehicle distance between a vehicle 20 and another vehicle 20 is shorter than a predetermined distance.

[0106] According to the above configuration, the following distance warning system 10 reduces erroneous determination of the following distance in the server 100, and can determine the following distance of the vehicle 20 more accurately.

[0107] The following distance warning device 201 according to the fourth embodiment includes a following distance warning acquisition unit 211 that acquires a following distance warning notification from the server 100. The following distance warning notification is transmitted to the vehicle 20 when the server 100 determines the following distances between the multiple vehicles 20 based on vehicle information including position information acquired from the multiple vehicles 20 and determines that a following distance warning notification is necessary for the vehicle 20. The following distance warning device 201 also includes a determination unit information acquisition unit 212 that acquires determination unit information indicating a determination status of the following distance by the in-vehicle device 200 provided in the vehicle. The following distance warning device 201 also includes a warning status determination unit 213 that determines whether or not the determination status of the vehicle is a first process for issuing a following distance warning based on the determination unit information. The following distance warning device 201 also includes a determination status determination unit 214 that determines whether or not the determination status of the vehicle is a second process for determining the following distance by the in-vehicle device 200 based on the determination unit information. The following distance warning device 201 includes a following distance warning control unit 215 that controls the in-vehicle device 200 to issue a warning when a following distance warning notification is transmitted from the server 100 and it is determined that the first process is not being executed and that the second process is not being executed. The first process corresponds to the second phase. The second process corresponds to the first phase.

[0108] According to the above configuration, the determination of the inter-vehicle distance by the inter-vehicle distance warning device 201 reflects the result of the inter-vehicle distance determination performed by the server 100 in addition to the inter-vehicle distance determination performed by the vehicle 20. Therefore, the inter-vehicle distance warning device 201 can prevent the failure to detect the preceding vehicle and issue a more appropriate inter-vehicle distance warning.

[0109] The following distance warning method according to the fifth aspect is a following distance warning method executed by a computer. The following distance warning method acquires a following distance warning notification from a server 100. The following distance warning notification is transmitted to the vehicle 20 when the server 100 judges the following distances between the multiple vehicles 20 based on vehicle information including position information acquired from the multiple vehicles 20 and judges that a following distance warning notification is necessary for the vehicle 20. The following distance warning method also acquires determination unit information indicating a determination status of the following distance by the vehicle-mounted device 200 provided in the vehicle. The following distance warning method also judges, based on the determination unit information, whether the determination status of the vehicle is a first process for issuing a following distance warning or not. The following distance warning method also judges, based on the determination unit information, whether the determination status of the vehicle is a second process for determining the following distance by the vehicle-mounted device 200 or not. Furthermore, the following distance warning method controls the vehicle-mounted device 200 to issue a warning when a following distance warning notification is transmitted from the server 100 and it is determined that the first process is not being executed and that the second process is not being executed. The first process corresponds to the second phase. The second process corresponds to the first phase.

[0110] According to the above configuration, the determination of the distance between vehicles by the vehicle distance method reflects the result of the distance determination performed by the server 100 in addition to the distance determination performed by the vehicle 20. Therefore, the vehicle distance warning method can prevent the failure to detect the preceding vehicle and can issue a warning of the distance between vehicles more appropriately. [Explanation of symbols]

[0111] 10. Vehicle Distance Warning System 20 Vehicles 40 Network 100 Servers 110, 210 Control unit 111 Vehicle Information Acquisition Department 112 Surrounding vehicle detection unit 113 Inter-vehicle distance warning judgment unit 114 Inter-vehicle distance warning notification section 120, 220 storage section 121 Vehicle Information DB 130 Input / Output Interface 140 Communication Interface 200 Onboard equipment 201 Inter-vehicle distance warning device 211 Inter-vehicle distance warning acquisition unit 212 Judgment section information acquisition section 213 Alarm status judgment unit 214 Judgment Status Judgment Section 215 Vehicle distance warning control unit 221 Inter-vehicle distance warning information DB 222 Judgment section information DB

Claims

1. A vehicle distance warning system including a vehicle distance warning device provided in a vehicle and a server, The server, A vehicle information acquisition unit that acquires vehicle information including vehicle position information from a plurality of the vehicles; a surrounding vehicle determination unit that determines whether or not another vehicle is present around the vehicle based on the vehicle information; a vehicle-to-vehicle distance warning determination unit that determines whether or not a warning needs to be issued for a vehicle-to-vehicle distance between the vehicle and the other vehicle when the other vehicle is present around the vehicle; a vehicle-to-vehicle distance warning notification unit that transmits a vehicle-to-vehicle distance warning notification to the vehicle when the vehicle-to-vehicle distance warning determination unit determines that a warning is necessary; The vehicle distance warning device includes: a vehicle-to-vehicle distance warning acquisition unit that acquires the vehicle-to-vehicle distance warning notification transmitted from the server; a determination unit information acquisition unit that acquires determination unit information indicating a state of determination of a vehicle distance by an on-board device provided in the vehicle; a warning status determination unit that determines whether or not the determination status of the host vehicle is a first process for issuing a vehicle distance warning based on the determination unit information; a determination status determination unit that determines whether the determination status of the host vehicle is a second process of determining a vehicle distance in the on-board device based on the determination unit information; a vehicle-to-vehicle distance warning control unit that controls the vehicle-mounted device to issue a warning when the vehicle-to-vehicle distance warning notification is transmitted from the server and when it is determined that the first process is not being executed and the second process is not being executed; A vehicle distance warning system having the same.

2. The vehicle information further includes travel direction information and speed information of the vehicle, The vehicle distance warning system according to claim 1 , wherein the vehicle distance warning determination unit determines the vehicle distance based on the position information, the traveling direction information, and the speed information of the vehicle, which are included in the vehicle information.

3. 3. The vehicle distance warning system according to claim 2, wherein the vehicle distance warning determination unit determines that a warning is necessary when the traveling directions indicated in the traveling direction information of a plurality of the vehicles are the same direction and the vehicle distance between the vehicle and another vehicle is shorter than a predetermined distance.

4. a vehicle-to-vehicle distance warning acquisition unit that acquires, from the server, a vehicle-to-vehicle distance warning notification to be transmitted to the vehicle, the vehicle-to-vehicle distance warning notification being transmitted to the vehicle when it is determined that a vehicle-to-vehicle distance warning notification is required, the vehicle-to-vehicle distance warning notification being transmitted to the vehicle, the vehicle-to-vehicle distance warning notification acquisition unit that determines, in the server, vehicle distances between the plurality of vehicles based on vehicle information including position information acquired from the plurality of vehicles, and a vehicle-to-vehicle distance warning notification being transmitted to the vehicle when it is determined that a vehicle-to-vehicle distance warning notification is required; a determination unit information acquisition unit that acquires determination unit information indicating a state of determination of a vehicle distance by an on-board device provided in the vehicle; a warning status determination unit that determines whether or not the determination status of the host vehicle is a first process for issuing a vehicle distance warning based on the determination unit information; a determination status determination unit that determines whether the determination status of the host vehicle is a second process of determining a vehicle distance in the on-board device based on the determination unit information; a vehicle-to-vehicle distance warning control unit that controls the vehicle-mounted device to issue a warning when the vehicle-to-vehicle distance warning notification is transmitted from the server and when it is determined that the first process is not being executed and the second process is not being executed; A vehicle distance warning device comprising:

5. A vehicle distance warning method executed by a computer, comprising: a vehicle distance warning notification transmitted from a server, the vehicle distances between a plurality of vehicles being determined based on vehicle information including position information acquired from the plurality of vehicles in the server, and when it is determined that a vehicle distance warning notification is required for the vehicle, the vehicle distance warning notification being transmitted to the vehicle is acquired from the server; Obtaining determination unit information indicating a state of determination of a vehicle distance by an on-board device provided in the vehicle; determining whether or not the determination status of the host vehicle is in a state where a first process for issuing a warning about a vehicle distance is being executed based on the determination unit information; determining whether or not the determination status of the host vehicle is a second process for determining a vehicle distance in the vehicle-mounted device based on the determination unit information; A vehicle-to-vehicle distance warning method, which controls the vehicle-mounted device to issue an alert when the vehicle-to-vehicle distance warning notification is sent from the server and it is determined that the judgment status is not that the first process is being executed and that the second process is not being executed.

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