Driving assistance device and driving assistance method

Abstract

A driving assistance device (100) comprises a host-vehicle information acquisition unit (11), a map information acquisition unit (12), an other-vehicle information acquisition unit (15), an assessment-target road identification unit (16), and a relative position assessment unit (17). In the case where two-lane links are connected to a first node ahead of the host vehicle, the assessment-target road identification unit extracts one or more second nodes present within a threshold distance. In the case where the second nodes are connected to the two-lane links, the assessment-target road identification unit assesses the first node and the second nodes as nodes in a complex intersection composed of one or more nodes to which the two-lane links are connected, and identifies an assessment-target road from among the links connected to said nodes.

Description

Driving assistance device and driving assistance method

[0001] The present disclosure relates to a driving assistance device and a driving assistance method.

[0002] Driving assistance systems that utilize V2X (Vehicle to X) technology, which enables communication and collaboration between vehicles and various other devices, have been developed. For example, a driving assistance device is known that uses map information to identify an intersection ahead on a road on which a vehicle is traveling and detects other vehicles traveling on other roads connected to the intersection (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2016-21125

[0004] Complex intersections where two lines intersect are made up of multiple nodes. Conventional driving assistance systems identify an intersection as a single node and detect other vehicles traveling on links connected to that node. As a result, conventional driving assistance systems have the problem of being unable to detect other vehicles traveling on links connected to nodes other than the one ahead at an intersection made up of multiple nodes.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a driving assistance device that can detect other vehicles traveling on links connected to nodes other than the one node ahead at an intersection made up of multiple nodes.

[0006] The driving assistance device disclosed herein includes a host vehicle information acquisition unit that acquires host vehicle information including the position, speed, and direction of travel of the host vehicle; a map information acquisition unit that acquires map information based on the position of the host vehicle; an other vehicle information acquisition unit that acquires other vehicle information including the position, speed, and direction of travel of other vehicles traveling around the host vehicle; a target road identification unit that identifies an opposing road to the host vehicle's road of travel as a target road on which other vehicles are traveling; and a relative position determination unit that determines the relative position of the host vehicle and other vehicles traveling on the target road identified by the target road identification unit based on the host vehicle information and other vehicle information. The target road identification unit then determines, based on map information, whether a double-line link is connected to a first node ahead of the link on which the vehicle is traveling, and if a double-line link is connected to the first node, determines that the first node is a node within a complex intersection made up of one or more nodes to which the double-line link is connected, sequentially follows the links connected to the first node starting from the first node to extract one or more second nodes that exist within a predetermined threshold distance, determines whether the extracted one or more second nodes are connected to the double-line link, and if one or more second nodes are connected to the double-line link, determines that the second nodes are nodes within the complex intersection, identifies the road on which the vehicle is traveling from among the links connected to the node within the complex intersection, and identifies an opposite road to the road on which the vehicle is traveling as the target road, and if a double-line link is not connected to the first node, identifies an opposite road to the road on which the vehicle is traveling from among the links connected to the first node as the target road.

[0007] In the driving assistance device disclosed herein, the determination target road identification unit determines, based on map information, whether a double-lined link is connected to a first node ahead of the link on which the vehicle is traveling, and if a double-lined link is connected to the first node, determines that the first node is a node within a complex intersection made up of one or more nodes to which the double-lined link is connected, sequentially follows the links connected to the first node starting from the first node to extract one or more second nodes that exist within a predetermined threshold distance, determines whether the one or more extracted second nodes are connected to the double-lined link, and if one or more second nodes are connected to the double-lined link, determines that the second nodes are nodes within the complex intersection, and identifies the road on which the vehicle is traveling from among the links connected to the nodes within the complex intersection, and identifies the opposite road to the road on which the vehicle is traveling as the determination target road.Therefore, at an intersection made up of multiple nodes, it is possible to detect other vehicles traveling on links connected to nodes other than the one node ahead.

[0008] FIG. 1 is an overall configuration diagram of a driving assistance device according to embodiment 1. FIG. 2 is a hardware configuration diagram of the driving assistance device according to embodiment 1. FIG. 3 is a functional block diagram of the driving assistance device according to embodiment 1. FIG. 4 is a flowchart illustrating the operation of the driving assistance device according to embodiment 1. FIG. 5 is a flowchart illustrating the operation of a determination target road specification unit of the driving assistance device according to embodiment 1. FIG. 6 is a diagram illustrating the operation of the determination target road specification unit of the driving assistance device according to embodiment 1. FIG. 7 is a flowchart illustrating the operation of the determination target road specification unit of the driving assistance device according to embodiment 1. FIG. 8 is a diagram illustrating the operation of the determination target road specification unit of the driving assistance device according to embodiment 1. FIG. 9 is a diagram illustrating the operation of the determination target road specification unit of the driving assistance device according to embodiment 2. FIG. 10 is a diagram illustrating the operation of the determination target road specification unit of the driving assistance device according to embodiment 3.

[0009] Hereinafter, a driving assistance device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the same reference numerals in the various drawings indicate the same or corresponding parts.

[0010] Embodiment 1. FIG. 1 is an overall configuration diagram of a driving assistance device according to Embodiment 1. A driving assistance device 100 according to this embodiment is mounted on each of a host vehicle 1 and a plurality of other vehicles 2. Information is shared between the host vehicle 1 and the plurality of other vehicles 2 via wireless communication. The driving assistance device 100 has vehicle-to-vehicle communication and driving assistance functions. The driving assistance device 100 generates a transmission message including vehicle information such as position, speed, and direction of travel, and transmits the transmission message to surrounding vehicles. The driving assistance device 100 also receives messages transmitted from surrounding vehicles and uses the vehicle information included in the received messages in its driving assistance function. For example, the driving assistance device 100 determines the possibility of a collision between the host vehicle and another vehicle and issues an alert to the driver, or outputs a driving command to activate an automatic brake.

[0011] FIG. 2 is a hardware configuration diagram of a driving assistance device according to this embodiment. The driving assistance device 100 according to this embodiment is configured with a processor 101, a memory 102, a wireless communication device 103, and an in-vehicle network interface 104. The processor 101 is an arithmetic processing unit that executes a single or multiple programs stored in the memory 102. Although not shown, the memory 102 includes a volatile storage device such as a random access memory and a non-volatile storage device such as a flash memory. Alternatively, a hard disk storage device may be used instead of the flash memory. The volatile storage device temporarily stores an execution program for the driving assistance device and data required to execute the program. The non-volatile storage device stores the execution program for the driving assistance device. The wireless communication device 103 is a wireless communication device that communicates with an external network and is configured with a receiving unit and a transmitting unit. The wireless communication device 103 transmits and receives messages for vehicle-to-vehicle communication. The in-vehicle network interface 104 is a wired communication interface for communicating with an ECU (Electronic Control Unit), on-board sensors, and a map data storage device of a vehicle equipped with the driving assistance device. Specifically, the in-vehicle network interface 104 is a sensor interface, Ethernet (registered trademark), CAN (Controller Area Network), etc. Examples of on-board sensors include a GNSS (Global Navigation Satellite System) receiver, a vehicle speed sensor, an acceleration sensor, and a gyro sensor.

[0012] 3 is a functional block diagram of a driving assistance device 100 according to this embodiment. The driving assistance device 100 according to this embodiment includes a host vehicle information acquisition unit 11, a map information acquisition unit 12, a transmission message generation unit 13, a transmission / reception unit 14, an other vehicle information acquisition unit 15, a target road specification unit 16, a relative position determination unit 17, and a driving assistance information output unit 18.

[0013] The host vehicle information acquisition unit 11 acquires host vehicle information such as the host vehicle's position, speed, and traveling direction from the ECU, on-board sensors, etc. The host vehicle information acquisition unit 11 sends the acquired host vehicle information to the transmission message generation unit 13, the judgment target road identification unit 16, and the relative position determination unit 17. The map information acquisition unit 12 acquires map information according to the host vehicle's traveling position. The map information acquired by the map information acquisition unit 12 is not a high-definition three-dimensional map (HDMap: High-Definition Map) used in autonomous driving, etc., but a standard-definition map (SDMap: Standard Map) used in car navigation systems, etc. The map information acquisition unit 12 sends the acquired map information to the judgment target road identification unit 16. The transmission message generation unit 13 generates a transmission message that stores the host vehicle information received from the host vehicle information acquisition unit 11. The transmission message generation unit 13 sends the generated transmission message to the transmission / reception unit 14.

[0014] The transmitter / receiver 14 uses vehicle-to-vehicle communication to transmit the transmission message received from the transmission message generator 13 to other vehicles, and also receives messages storing other vehicle information from other vehicles. The transmitter / receiver 14 sends the received message to the other vehicle information acquirer 15. The other vehicle information acquirer 15 acquires other vehicle information such as the position, speed, and traveling direction of the other vehicle from the received message. The other vehicle information acquirer 15 sends the acquired other vehicle information to the relative position determiner 17.

[0015] The determination target road specifying unit 16 specifies, as a determination target road, a road on which another vehicle that may collide with the subject vehicle is traveling, based on the subject vehicle information received from the subject vehicle information acquisition unit 11 and the map information received from the map information acquisition unit 12. The operation of the determination target road specifying unit 16 will be described later. The determination target road specifying unit 16 sends the specified determination target road to the relative position determination unit 17.

[0016] The relative position determination unit 17 determines the relative position of the subject vehicle and another vehicle traveling on the subject road based on the subject road received from the subject road identification unit 16, the subject vehicle information received from the subject vehicle information acquisition unit 11, and the other vehicle information received from the other vehicle information acquisition unit 15. The relative position determination unit 17 sends the determined relative position of the subject vehicle and the other vehicle to the driving assistance information output unit 18. The driving assistance information output unit 18 determines whether or not it is necessary to output driving assistance information based on the received relative positions of the subject vehicle and the other vehicle. The driving assistance information output unit 18 determines whether or not it is necessary to output driving assistance information such as information notifying the subject vehicle of an approaching emergency vehicle or a warning that a wrong-way vehicle is approaching, based on the relative positions of the subject vehicle and the other vehicle. Furthermore, the driving assistance information output unit 18 can determine the possibility of a collision using a time-to-collision (hereinafter referred to as TTC) and determine whether or not it is necessary to output driving assistance information such as an alarm. TTC is the estimated time until a vehicle collides with another vehicle, and is the time during which a driving maneuver can be performed to avoid a collision.

[0017] Next, the operations of the determination target road identification unit 16, the relative position determination unit 17, and the driving assistance information output unit 18 will be described. First, terminology will be described. In map information, a road network is represented by a combination of nodes and links. A node is an intersection, a dead end of a road, etc., represented by a point. A link is a road section between nodes represented by a line. Furthermore, a double line is a portion where, when a road network is represented by nodes and links, the upper and lower lanes are separated and represented by two links. A single line is a portion where, when a road network is represented by nodes and links, the upper and lower lanes are represented by a single link.

[0018] 4 is a flowchart illustrating the operation of the driving assistance device according to this embodiment, which is implemented by the determination target road specification unit 16, the relative position determination unit 17, and the driving assistance information output unit 18.

[0019] First, in step S01, the determination target road identification unit 16 identifies a complex intersection from map information. A method for identifying a complex intersection in step S01 will be described later. Next, in step S02, the determination target road identification unit 16 identifies an opposing road to the road on which the vehicle is traveling and also identifies a determination target road. A method for identifying a determination target road in step S02 will also be described later.

[0020] In step S03, the relative position determination unit 17 determines whether or not another vehicle is traveling on the determination target road based on the determination target road and the other vehicle information. If it is determined in step S03 that another vehicle is not traveling on the determination target road (NO), the relative position determination unit 17 ends its operation.

[0021] If it is determined in step S03 that another vehicle is traveling on the determination target road (YES), the relative position determination unit 17 determines the relative position between the other vehicle traveling on the determination target road and the subject vehicle in step S04. The driving assistance information output unit 18 determines whether or not output of driving assistance information is necessary based on the relative position between the other vehicle and the subject vehicle in step S05. As an example of the determination in step S05, the driving assistance information output unit 18 determines that there is no possibility of a collision if the TTC is 3 seconds or more and determines that output of driving assistance information is unnecessary, and if the TTC is less than 3 seconds and determines that there is a possibility of a collision and determines that output of driving assistance information is necessary. If it is determined in step S05 that output of driving assistance information is unnecessary (NO), the driving assistance information output unit 18 terminates its operation. If it is determined in step S05 that output of driving assistance information is necessary (YES), the driving assistance information output unit 18 outputs driving assistance information in step S06.

[0022] Next, a description will be given of the operation of the determination target road specification unit 16 in step S01 of the flowchart in Fig. 4. Fig. 5 is a flowchart illustrating the operation of the determination target road specification unit 16 of the driving assistance device according to this embodiment.

[0023] First, in step S11, the determination target road identification unit 16 uses map information to determine whether a two-line link is connected to a node ahead of the link on which the vehicle is traveling. If in step S11 a two-line link is not connected to the node ahead (NO), the determination target road identification unit 16 terminates its operation. If in step S11 a two-line link is connected to the node ahead (YES), the determination target road identification unit 16 determines in step S12 that the node is a node within a complex intersection. Here, a complex intersection is defined as an intersection made up of one or more nodes connected by two-line links. Note that in step S11, if the node information in the map information includes information indicating that the node itself is a node within a complex intersection, that information may be used for the determination.

[0024] Next, in step S13, the determination target road identification unit 16 traces the links connected to a node determined to be within a complex intersection as a starting point, and extracts undetermined nodes within a threshold distance. FIG. 6 is a diagram illustrating the operation of the determination target road identification unit in step S13. In FIG. 6, circles represent nodes and arrows represent links. FIG. 6 shows an example of an intersection where two lines intersect. As shown in FIG. 6, node N1, located ahead of link L1 on which the vehicle 1 is traveling, is determined to be a node to which a link of two lines is connected. In FIG. 6, the threshold distance from node N1 is indicated by a dashed line. The threshold distance is set to, for example, 50 m. In step S13, first, links L2, L3, and L4 connected to node N1 are traced to extract nodes N2 and N3 within the threshold distance. Next, links L5, L6, L7, L8, L9, and L10 connected to nodes N2 and N3 are traced to extract node N4 within the threshold distance. Furthermore, links L11 and L12 connected to node N4 are traced to extract nodes within the threshold distance, but at this time other nodes within the threshold distance are not extracted.

[0025] In step S13, the determination target road specification unit 16 extracts undetermined nodes by tracing links connected to a node starting from the node. The reason for this is to exclude from the determination targets nodes that are not directly related to the road on which the vehicle is traveling, for example, nodes that have an intersection above or below an overpass and are within the threshold distance.

[0026] Next, in step S14, the determination target road specification unit 16 determines whether or not there are any undetermined nodes. If there are any undetermined nodes in step S14 (YES), the determination target road specification unit 16 proceeds to step S15. If there are no undetermined nodes in step S14 (NO), the determination target road specification unit 16 proceeds to step S17.

[0027] If the process proceeds to step S15, the determination target road identification unit 16 selects one node from the undetermined nodes and determines whether or not a two-line link is connected to the selected node. If a two-line link is not connected to the selected node in step S15 (NO), the determination target road identification unit 16 returns to step S14. If a two-line link is connected to the selected node in step S15 (YES), the determination target road identification unit 16 determines in step S16 that the node is a node within a complex intersection. Then, the determination target road identification unit 16 returns to step S14.

[0028] If the process proceeds to step S17, the determination target road specification unit 16 determines whether or not the determined nodes include a node within a newly specified complex intersection. If the determined nodes include a node within a newly specified complex intersection (YES in step S17), the determination target road specification unit 16 returns to step S14. If the determined nodes do not include a node within a newly specified complex intersection (NO in step S17), the determination target road specification unit 16 proceeds to step S18.

[0029] In step S18, the determination target road identification unit 16 identifies a surface surrounded by nodes in all complex intersections as one complex intersection. Figure 7 is a diagram for explaining that the determination target road identification unit 16 has identified a complex intersection in step S18. As shown in Figure 7, the determination target road identification unit 16 identifies the surface surrounded by nodes N1, N2, N3, and N4, indicated by diagonal lines, as a complex intersection.

[0030] Next, a description will be given of the operation of the determination target road specification unit 16 in step S02 of the flowchart in Fig. 4. Fig. 8 is a flowchart illustrating the operation of the determination target road specification unit of the driving assistance device according to this embodiment.

[0031] First, in step S21, the determination target road specification unit 16 specifies the link that is most likely to be traveled by the vehicle from among the links connected to the complex intersection, and specifies the link as the road on which the vehicle is traveling. One method for specifying the link that is most likely to be traveled by the vehicle is to rank the priority of each link based on the road type included in the map information, and select the link with the highest priority.

[0032] Next, in step S22, the determination target road identification unit 16 determines whether the link along which the vehicle is most likely to travel is a two-line link. If in step S22 the link along which the vehicle is most likely to travel is a two-line link (YES), the determination target road identification unit 16 proceeds to step S23. If in step S22 the link along which the vehicle is most likely to travel is not a two-line link (NO), the determination target road identification unit 16 proceeds to step S27.

[0033] When the process proceeds to step S23, the determination target road identification unit 16 identifies a paired link of the two-lined road to be paired with the link of the two-lined road. Fig. 9 is a diagram for explaining the operation of the determination target road identification unit in step S23. In Fig. 9, the solid arrow indicates link L6 on which the host vehicle is most likely to travel, the dashed arrow indicates a link on which the host vehicle is unlikely to travel, and the dashed-dotted arrow indicates link L12 on which link L6 is paired.

[0034] At this time, the target road identification unit 16 compares the parallel distance, road shape similarity, and number of lanes between the two-line link L12 that is paired with link L6, and if the parallel distance, road shape similarity, and number of lanes similarity are equal to or greater than a predetermined threshold, it identifies the two-line link as a pair.

[0035] Next, in step S24, the judgment target road identification unit 16 identifies the paired double-line link as an oncoming road. Next, in step S25, the judgment target road identification unit 16 determines whether or not the host vehicle travel road identified in step S21 is to be the judgment target road. If the host vehicle travel road is to be the judgment target road in step S25 (YES), the judgment target road identification unit 16 proceeds to step S26. If the host vehicle travel road is not to be the judgment target road in step S25 (NO), the judgment target road identification unit 16 proceeds to step S28.

[0036] On the other hand, if the process proceeds from step S22 to step S27, the judgment target road identification unit 16 identifies the link on which the host vehicle is most likely to travel as the oncoming road. Then, the judgment target road identification unit 16 proceeds to step S28. If the process proceeds to step S26, the judgment target road identification unit 16 identifies the oncoming road and the host vehicle traveling road as the judgment target roads. If the process proceeds to step S28, the judgment target road identification unit 16 identifies the oncoming road as the judgment target road. In this way, the judgment target road identification unit 16 identifies the judgment target road.

[0037] In this way, when a double-lined link is connected to a node ahead of the link on which the vehicle is traveling, the determination target road identification unit of the driving assistance device of this embodiment identifies the area surrounded by the node ahead and its surrounding nodes as a complex intersection.The determination target road identification unit then identifies the determination target road from among the links connected to the complex intersection.Furthermore, the relative position determination unit of the driving assistance device of this embodiment determines whether another vehicle is traveling on the determination target road based on the determination target road and other vehicle information.

[0038] The driving assistance device configured in this manner can detect other vehicles traveling on links connected to nodes other than the one ahead at a complex intersection made up of multiple nodes. Therefore, other vehicles traveling on links connected to multiple nodes can also be recognized as other vehicles with a possibility of collision. As a result, a vehicle equipped with the driving assistance device of this embodiment can improve safety at complex intersections.

[0039] In the driving assistance device of this embodiment, the threshold distance is set to 50 m. This threshold distance may be changed based on information about the number of lanes on a link connected to a node ahead of the link on which the vehicle is traveling. By changing the threshold distance based on information about the number of lanes, the search distance for nodes within a complex intersection can be set according to the size of the intersection, thereby improving safety.

[0040] Furthermore, in the driving assistance device of this embodiment, the road on which the vehicle is traveling can be included in the roads to be determined, so that vehicles traveling in the wrong direction can also be recognized as vehicles with which there is a possibility of collision, thereby further improving safety.

[0041] Although the driving assistance device 100 of the present embodiment includes the transmission message generator 13, the transmitter / receiver 14, and the driving assistance information output unit 18, the driving assistance device 100 does not necessarily have to include these functions. For example, the functions of the transmission message generator and the transmitter / receiver may be provided by a V2X communication module provided separately from the driving assistance device. Furthermore, the function of the driving assistance information output unit may be provided by an ADAS-ECU (Advanced Driver Assistance Systems-Electronic Control Unit) having various sensors provided separately from the driving assistance device.

[0042] Embodiment 2 The configuration of a driving assistance device according to embodiment 2 is the same as the configuration of the driving assistance device according to embodiment 1. In this embodiment, an operation of the driving assistance device when it is detected that the node ahead of the link on which the host vehicle is traveling is a node where the line changes from a single line to a double line will be described.

[0043] FIG. 10 is a diagram illustrating the operation of the determination target road identification unit in the driving assistance device according to this embodiment. As shown in FIG. 10 , node N1 ahead of link L1 on which the host vehicle 1 is traveling is assumed to be a node where a line changes from a single line to a double line. That is, at node N1, the single line link L1 changes to double line links L20 and L21. In this case, a deformed branch link L22 is set between the single line and the double line in the map information. The deformed branch link L22 has a link shape that deviates from the actual center line locus of the double line in order to connect the two double line links to a single node. The link along which the host vehicle is most likely to travel is then link L20. In this case, the determination target road identification unit according to this embodiment does not use branch link L22 when determining a link to be paired with the link along which the host vehicle is most likely to travel, but instead determines a link to be paired with the link along which the host vehicle is most likely to travel at a position indicated as a determination position ahead of branch link L22.

[0044] The driving assistance device configured in this way can accurately identify the oncoming road even at a complex intersection where a single lane changes to a double lane.

[0045] In this embodiment, the operation is described for the case where the node ahead of the link on which the vehicle is traveling is a node where a line changes from a single line to a double line. Even when the node ahead of the link on which the vehicle is traveling is a node where a line changes from a double line to a single line, the determination target road specification unit does not use a branch link when determining a link to be paired with the link on which the vehicle is most likely to travel, but determines a link ahead of that link to be paired.

[0046] Embodiment 3 The configuration of a driving assistance device according to embodiment 3 is similar to the configuration of the driving assistance device according to embodiment 1. In this embodiment, the forward distance is determined when identifying the road on which the host vehicle is traveling.

[0047] 11 is a diagram illustrating the operation of a determination target road specifying unit in the driving assistance device according to this embodiment. As shown in FIG. 11, the determination target road specifying unit in the driving assistance device according to this embodiment specifies the road on which the host vehicle is traveling up to a predetermined distance ahead. The predetermined distance ahead is, for example, 300 m. Note that the predetermined distance ahead may be a straight-line distance, but it is preferable that it be a distance along a road.

[0048] The driving assistance device configured in this way can identify roads on which the host vehicle is traveling up to a predetermined distance ahead, thereby expanding the roads to be determined up to that distance.

[0049] Although various exemplary embodiments are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0050] 1 Own vehicle, 2 Other vehicles, 11 Own vehicle information acquisition unit, 12 Map information acquisition unit, 13 Transmission message generation unit, 14 Transmitting / receiving unit, 15 Other vehicle information acquisition unit, 16 Determination target road identification unit, 17 Relative position determination unit, 18 Driving assistance information output unit, 100 Driving assistance device, 101 Processor, 102 Memory, 103 Wireless communication device, 104 In-vehicle network interface.

Claims

1. A vehicle information acquisition unit that acquires vehicle information including the vehicle's position, speed, and direction of travel, A map information acquisition unit that acquires map information based on the position of the vehicle, A unit for acquiring information on other vehicles, including the position, speed, and direction of travel of other vehicles traveling around the aforementioned vehicle, A road identification unit that identifies the road opposite to the road on which the vehicle is traveling as a road to be determined for other vehicles, A driving assistance device comprising: a relative position determination unit that determines the relative position between the other vehicle and the self-vehicle, based on the self-vehicle information and the other vehicle information, the other vehicle traveling on the road to be determined, which has been identified by the road to be determined unit; The road identification unit for determination determines, based on the map information, whether or not a double-line link is connected to the first node ahead of the link on which the vehicle is traveling. If a double-line link is connected to the first node, the first node is determined to be a node in a complex intersection composed of one or more nodes to which double-line links are connected, and one or more second nodes located within a predetermined threshold distance are extracted by sequentially following the links connected to the first node starting from the first node, and it is determined whether one or more of the extracted second nodes are connected to a double-line link, and if one or more of the second nodes are connected to a double-line link, the second nodes are determined to be nodes in the complex intersection, and the road on which the vehicle is traveling is identified from among the links connected to the nodes in the complex intersection, and the road opposite to the road on which the vehicle is traveling is identified as the road to be determined. If no double-line link is connected to the first node, the driving assistance device is characterized in that it identifies the road opposite to the road on which the vehicle is traveling as the road to be determined from among the links connected to the first node.

2. The driving assistance device according to claim 1, characterized in that the threshold distance is changed based on information about the number of lanes of the link connected to the first node.

3. The driving assistance device according to claim 1 or 2, characterized in that the road identification unit identifies the link most likely to be traveled by the vehicle from among the links connected to the nodes in the complex intersection as the road on which the vehicle is traveling, and if the link most likely to be traveled by the vehicle is a double-link, it identifies the pair of double-links to that link as the opposing road.

4. The driving assistance device according to claim 3, characterized in that the road identification unit for determination compares the parallel distance, similarity of road shape, and similarity of number of lanes between the two-line link that the vehicle is most likely to travel on and the other links, and identifies links where the parallel distance, similarity of road shape, and similarity of number of lanes are above a predetermined threshold as a pair of two-line links.

5. The driving assistance device according to claim 3, characterized in that when the road identification unit for determination detects that the first node is a node that changes from a single line to a double line, or from a double line to a single line, it uses the link in front of it to identify the paired link without using the deformed branch link set between the single line and the double line.

6. The driving assistance device according to claim 1 or 2, characterized in that the road identification unit for determination adds the road on which the vehicle is traveling to the roads for determination.

7. The driving assistance device according to claim 1 or 2, characterized in that the road identification unit for determination identifies the road on which the vehicle is traveling up to a predetermined distance ahead.

8. A vehicle information acquisition step that acquires vehicle information including the vehicle's position, speed, and direction of travel, A map information acquisition step, which acquires map information based on the position of the vehicle, A step of acquiring information on other vehicles, including the position, speed, and direction of travel of other vehicles traveling around the aforementioned vehicle, A step to identify a road to be determined, in which the road opposite to the road on which the vehicle is traveling is identified as a road to be determined to be traveled by the other vehicle, A driving assistance method comprising: a relative position determination step that determines the relative position between the other vehicle and the self-vehicle, based on the self-vehicle information and the other vehicle information, the other vehicle traveling on the road to be determined, which was identified in the road to be determined step; The step of identifying the road to be determined includes determining, based on the map information, whether or not a double-line link is connected to the first node ahead of the link on which the vehicle is traveling, If a double-line link is connected to the first node, the process includes the steps of determining that the first node is a node in a complex intersection composed of one or more nodes to which the double-line link is connected; sequentially tracing the links connected to the first node starting from the first node to extract one or more second nodes that are within a predetermined threshold distance; determining whether the extracted one or more second nodes are connected to a double-line link; determining that if one or more second nodes are connected to a double-line link, those second nodes are nodes in the complex intersection; and identifying the road on which the vehicle is traveling from among the links connected to the nodes in the complex intersection, and identifying the road opposite to the road on which the vehicle is traveling as the road to be determined. A driving assistance method characterized by having the step of identifying the road opposite to the road on which the vehicle is traveling from among the links connected to the first node as the road to be determined if no double-line link is connected to the first node.