Subsequent vehicle approach notifying device

Abstract

To prevent a driver of the own vehicle from becoming impatient.SOLUTION: A subsequent vehicle approach notifying device comprises: a detection device (18) capable of detecting the approaching of a subsequent vehicle (2) to the own vehicle (1); and a notifying device (22) that notifies a driver of the own vehicle (1) of the approaching of the subsequent vehicle (2) to the own vehicle (1). The subsequent vehicle approach notifying device discriminates whether or not the own vehicle (1) can change lanes from a fast lane (35a) to a driving lane (34a) upon detection of the approaching of the subsequent vehicle (2) to the own vehicle (1) while the own vehicle is traveling in the fast lane (35a). The subsequent vehicle approach notifying device notifies the driver of the own vehicle (1) of the approaching of the subsequent vehicle (2) to the own vehicle (1) if discrimination has been made that a lane change is possible, and stops notifying the driver of the own vehicle (1) of the approaching of the subsequent vehicle (2) to the own vehicle (1) if the lane change is not permitted.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a following vehicle approach notification device.

Background Art

[0002] When the host vehicle is traveling in the overtaking lane and a following vehicle rapidly approaches the host vehicle and then the state where the following vehicle approaches the host vehicle continues for a certain period of time or more, a warning device that issues a warning to the driver of the host vehicle, such as "The following vehicle is rapidly approaching", is known (see, for example, Patent Document 1). By issuing such a warning, the driver of the host vehicle is made aware of the rapid approach of the following vehicle, and thereby the driver of the host vehicle is urged to change lanes. Note that in this warning device, when the host vehicle is not traveling in the overtaking lane, even if a following vehicle rapidly approaches the host vehicle, such a warning is not issued to the driver of the host vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the host vehicle is in a situation where lane change is impossible and the host vehicle is traveling in the overtaking lane, if a warning is issued to the driver of the host vehicle on the grounds that a following vehicle rapidly approaches the host vehicle, there is a problem that it will exacerbate the driver's anxiety of the host vehicle.

Means for Solving the Problems

[0005] In order to solve such problems, according to the present invention, there are provided a detection device capable of detecting the approach of a following vehicle to the host vehicle, a notification device for notifying the driver of the host vehicle of the approach of a rear vehicle to the host vehicle, and a processor. This processor acquires information regarding the lane of the road on which the host vehicle is traveling, while the host vehicle is traveling in the passing lane, when the approach of a following vehicle to the host vehicle is detected by a detection device, determines whether it is possible to change the lane of the host vehicle from the passing lane to the driving lane, if it is determined that it is possible to change the lane of the host vehicle from the passing lane to the driving lane, causes the approach of the following vehicle to the host vehicle to be notified to the driver of the host vehicle by a notification device, if it is determined that it is not possible to change the lane of the host vehicle from the passing lane to the driving lane, a following vehicle approach notification device is provided that cancels the notification to the driver of the host vehicle of the approach of the following vehicle to the host vehicle by the notification device.

Advantages of the Invention

[0006] By canceling the notification to the driver of the host vehicle of the approach of a following vehicle when it is not possible to change the lane of the host vehicle from the passing lane to the driving lane, it is possible to suppress the promotion of the anxiety of the driver of the host vehicle.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0008] First, the terms used in the present invention will be explained. In the present invention, the vehicle to be controlled according to the present invention is referred to as the "host vehicle", and the vehicle traveling following the host vehicle is referred to as the "following vehicle". FIG. 1 schematically shows the host vehicle 1 as viewed from above, and FIG. 2 shows the functional configuration of the host vehicle 1 shown in FIG. 1. Note that this host vehicle 1 is capable of both manual driving and automatic driving. Referring to FIG. 2, 10 indicates a vehicle drive unit for applying a driving force to the drive wheels of the vehicle 1, 11 indicates a braking device for braking the vehicle 1, 12 indicates a steering device for steering the vehicle 1, and 13 indicates an electronic control unit mounted in the vehicle 1, respectively. As shown in FIG. 2, the electronic control unit 13 consists of a digital computer and includes a CPU (processor) 15, a memory 16 composed of a ROM and a RAM, and an input / output port 17, which are connected to each other by a bidirectional bus 14.

[0009] On the other hand, as shown in FIG. 2, a detection device 18 including various sensors necessary for the host vehicle 1 to perform automatic driving is installed in the host vehicle 1. This detection device 18 includes sensors for detecting the state of the host vehicle 1 and sensors for detecting the surroundings of the host vehicle 1. In this case, as the sensors for detecting the state of the host vehicle 1, an acceleration sensor, a speed sensor, an azimuth sensor, and a geomagnetic sensor are used, and as the sensors for detecting the surroundings of the host vehicle 1, cameras for photographing the front, side, and rear of the host vehicle 1, and lidar (LIDAR), radar, clearance sonar, etc. for detecting the front, side, and rear of the host vehicle 1 are used.

[0010] FIG. 1 shows an example of sensors installed in the host vehicle 1. In the example shown in FIG. 1, the host vehicle 1 is equipped with front cameras 3a and 3b for photographing the front of the host vehicle 1, a rear camera 4 for photographing the rear of the host vehicle 1, a long-range millimeter-wave radar 5 that emits millimeter waves toward the front of the host vehicle 1, medium-range millimeter-wave radars 6a, 6b, 6c, and 6d that emit millimeter waves toward the sides of the host vehicle 1, lidars 7a, 7b, 7c, and 7d that irradiate laser light toward the sides of the host vehicle 1, and a clearance sonar 8 that emits ultrasonic waves toward the rear of the host vehicle 1. In addition, a line-of-sight detection device 9 for detecting the direction of the driver's line of sight is installed inside the vehicle cabin. This line-of-sight detection device 9 has, for example, an infrared LED that irradiates infrared rays onto the driver's eyeball and an infrared camera that detects the reflected infrared light on the cornea, and the direction of the driver's line of sight is detected from the reflected infrared light on the cornea. Note that the installation methods of the cameras and sensors shown in FIG. 1 are merely examples, and there are various methods for installing these cameras and sensors.

[0011] Returning to FIG. 2 again, the host vehicle 1 is provided with a GNSS (Global Navigation Satellite System) receiver 19, a map data storage device 20, a navigation device 21, and a notification device 22 that notifies the driver of the surrounding situation. The GNSS receiver 19 can detect the current position of the host vehicle 1 (for example, the latitude and longitude of the host vehicle 1) based on information obtained from a plurality of artificial satellites. Therefore, the current position of the host vehicle 1 can be acquired by this GNSS receiver 19. As this GNSS receiver 19, for example, a GPS receiver is used. In addition, the map data storage device 20 stores map data and the like necessary for the travel of the host vehicle 1. This map data also includes information about roads. These various sensors 18, GNSS receiver 19, map data storage device 20, navigation device 21, and notification device 22 are connected to an electronic control unit 13. In addition, the vehicle 1 is equipped with a communication device 23 connected to the electronic control unit 13.

[0012] In the example shown in FIG. 2, the host vehicle 1 can be manually driven, and when there is a request for travel control by automatic driving for the host vehicle 1, it is possible to cause the host vehicle 1 to perform travel control by automatic driving. In the example shown in FIG. 2, the vehicle drive unit 10 of the host vehicle 1 is composed of an electric motor driven by a secondary battery or an electric motor driven by a fuel cell, and the drive wheels are driven and controlled by these electric motors according to the output signal of the electronic control unit 13. Further, in the example shown in FIG. 2, when there is a request for travel control by automatic driving for the vehicle 1, the braking control of the vehicle 1 is performed by the braking device 11 according to the output signal of the electronic control unit 13, and the steering control of the vehicle 1 is also performed by the steering device 12 according to the output signal of the electronic control unit 13.

[0013] FIGS. 3 and 4 show the road 30 as viewed from above. In FIGS. 3 and 4, 31 is the median strip, 32 and 33 are white lines, 34a and 34b are driving lanes, and 35a and 35b are passing lanes, respectively. Further, FIGS. 3 and 4 show a case where the host vehicle 1 is traveling in the passing lane 35a and the following vehicle 2 is traveling in the passing lane 35a while following the host vehicle 1. Furthermore, FIGS. 3 and 4 show a case where other vehicles 36, 37, and 38 are traveling in the driving lane 34a.

[0014] Now, FIGS. 3 and 4 show a situation where the following vehicle 2 approaches the host vehicle 1 while the host vehicle 1 is traveling in the passing lane 35a, and the following vehicle 2 is performing tailgating on the host vehicle 1. Such tailgating is difficult for the driver of the host vehicle 1 to endure, and the driver of the host vehicle 1 generally hopes to be released from such a tailgating state. In this case, as a method of releasing the driver of the host vehicle 1 from such a tailgating state, when the following vehicle 2 approaches the host vehicle 1 while the host vehicle 1 is traveling in the passing lane 35a, it is conceivable to notify the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1 and urge the driver of the host vehicle 1 to change lanes to the driving lane 34a.

[0015] By the way, when the driver of the host vehicle 1 is notified of the approach of the following vehicle 2 to the host vehicle 1 in this way, as shown in FIG. 4, if there is a driving lane space 40 into which the host vehicle 1 can enter in the driving lane 34a located in front of the host vehicle 1, it is possible to change the lane of the host vehicle 1 from the overtaking lane 35a to the driving lane 34a. Therefore, it becomes possible to release the driver of the host vehicle 1 from the aggressive driving state. On the other hand, when the driver of the host vehicle 1 is notified of the approach of the following vehicle 2 to the host vehicle 1, as shown in FIG. 3, the intervals between the other vehicles 36, 37, 38 traveling in the driving lane 34a located in front of the host vehicle 1 are narrow, and there is no driving lane space 40 into which the host vehicle 1 can enter as shown in FIG. 4 in the driving lane 34a located in front of the host vehicle 1. In this case, it is impossible to change the lane of the host vehicle 1 from the overtaking lane 35a to the driving lane 34a. When it is impossible to change the lane of the host vehicle 1 from the overtaking lane 35a to the driving lane 34a in this way, notifying the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1 only exacerbates the driver's anxiety and has no merit at all.

[0016] Therefore, in the present invention, when the following vehicle 2 approaches the host vehicle 1 while the host vehicle 1 is traveling in the overtaking lane 35a, if it is possible to change the lane of the host vehicle 1 from the overtaking lane 35a to the driving lane 34a, the approach of the following vehicle 2 to the host vehicle 1 is notified to the driver of the host vehicle 1, and if it is impossible to change the lane of the host vehicle 1 from the overtaking lane 35a to the driving lane 34a, the notification of the approach of the following vehicle 2 to the host vehicle 1 to the driver of the host vehicle 1 is cancelled.

[0017] In order to achieve the present invention, in the present invention, as shown in FIG. 2, a detection device 18 capable of detecting the approach of a following vehicle 2 to the host vehicle 1 and a notification device 22 for notifying the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1 are provided. In this case, in the detection device 18, for example, based on the image data of the rear camera 4 and the detection output of the clearance sonar 8 shown in FIG. 1, the approach of the following vehicle 2 to the host vehicle 1 is detected. For example, when the presence of the following vehicle 2 is confirmed based on the image data of the rear camera 4 and the distance between the host vehicle 1 and the following vehicle 2 calculated based on the detection output of the clearance sonar 8 is within the set distance range, it is determined that the following vehicle 2 has approached the host vehicle 1.

[0018] On the other hand, the notification of the approach of the following vehicle 2 to the host vehicle 1 by the notification device 22 is performed by text display, voice, or sound. When the notification of the approach of the following vehicle 2 is performed by text display, for example, on the display screen installed on the dashboard in the vehicle interior, displays such as "A following vehicle is approaching", "A following vehicle is approaching. Please change lanes in the driving lane" are made. In this case, using head-up display technology, words such as "A following vehicle is approaching" can also be projected on the front glass. When the notification of the approach of the following vehicle 2 is performed by voice, voices such as "A following vehicle is approaching", "A following vehicle is approaching. Please change lanes in the driving lane" are generated from the speaker installed on the dashboard in the vehicle interior. When the notification of the approach of the following vehicle 2 is performed by sound, a buzzer is installed in the vehicle interior and the buzzer is sounded. Thus, in the embodiment according to the present invention, the notification of the approach of the following vehicle 2 to the host vehicle 1 includes urging the driver to change lanes to the driving lane 34a of the host vehicle 1 by at least one of text display, voice, and sound.

[0019] In addition, in the embodiment according to the present invention, the detection device 18 detects whether there is a travel lane space 40 into which the host vehicle 1 can enter. In this case, the detection device 18 uses, for example, the image data of the front cameras 3a and 3b shown in FIG. 1, the detection output of the long-distance millimeter-wave radar 5, the detection output of the medium-distance millimeter-wave radar 6b, and the detection output of the lidar 7b to detect whether there is a travel lane space 40 into which the host vehicle 1 can enter. In this case, even when it is determined based on the image data of these front cameras 3a and 3b that there are no other vehicles in the travel lane 34a located in front of the host vehicle 1, it is determined that there is a travel lane space 40 into which the host vehicle 1 can enter.

[0020] To give a specific example, based on the image data of these front cameras 3a and 3b, as shown in FIG. 3, when it is determined that other vehicles 36, 37, and 38 are traveling in the travel lane 34a located in front of the host vehicle 1, or as shown in FIG. 4, when it is determined that other vehicles 36 and 37 are traveling in the travel lane 34a located in front of the host vehicle 1, the inter-vehicle distance from the host vehicle 1 to the nearest other vehicle 36 to the host vehicle 1 is calculated based on the image data of these front cameras 3a and 3b. When this inter-vehicle distance is equal to or greater than the set inter-vehicle distance, it is determined that there is a travel lane space 40 into which the host vehicle 1 can enter. On the other hand, when the inter-vehicle distance from the host vehicle 1 to the nearest other vehicle 36 to the host vehicle 1 is less than the set inter-vehicle distance, the inter-vehicle distance between the two nearest vehicles 36 and 37 to the host vehicle 1 is calculated based on the image data of these front cameras 3a and 3b. As shown in FIG. 4, when this inter-vehicle distance is equal to or greater than the set inter-vehicle distance, it is determined that there is a travel lane space 40 into which the host vehicle 1 can enter.

[0021] FIG. 5 shows a routine for executing a following vehicle approach notification process for notifying the driver of the host vehicle 1 that the following vehicle 2 has approached the host vehicle 1. This routine is executed by an interrupt at regular intervals within the electronic control unit 13 of the host vehicle 1.

[0022] Referring to FIG. 5, first, in step 50, information regarding the lane of the road on which the host vehicle 1 is currently traveling is acquired. This information regarding the lane includes information on whether the lane is a single lane or a multi-lane. Note that this information regarding the lane can also be obtained from the image data of the front cameras 3a and 3b, or can also be obtained from the map data stored in the map data storage device 20 and the current position of the host vehicle 1. Next, in step 51, it is determined whether the road on which the host vehicle 1 is currently traveling is a multi-lane road. When it is determined that the road on which the host vehicle 1 is currently traveling is a multi-lane road, the process proceeds to step 52, and based on the image data of the front cameras 3a and 3b, etc., it is determined whether the host vehicle 1 is currently traveling in the overtaking lane. In the example shown in FIGS. 3 and 4, it is determined whether the host vehicle 1 is traveling in the lane on the median strip 31 side. When it is determined that the host vehicle 1 is traveling in the overtaking lane, the process proceeds to step 53.

[0023] In step 53, the presence of the following vehicle 2 is detected based on the image data of the rear camera 4, and the distance between the host vehicle 1 and the following vehicle 2 is calculated based on the detection output of the clearance sonar 8. Next, in step 54, it is determined whether the following vehicle 2 has approached the host vehicle 1. In this case, when the presence of the following vehicle 2 is confirmed based on the image data of the rear camera 4 and the distance between the host vehicle 1 and the following vehicle 2 calculated based on the detection output of the clearance sonar 8 is within the set distance range, it is determined that the following vehicle 2 has approached the host vehicle 1. When it is determined that the following vehicle 2 has approached the host vehicle 1, the process proceeds to step 55.

[0024] In step 55, using the image data from the front cameras 3a and 3b, the detection output of the long-range millimeter-wave radar 5, the detection output of the mid-range millimeter-wave radar 6b, and the detection output of the lidar 7b, a detection is performed for the driving lane space 40 in front of the host vehicle 1 into which the host vehicle 1 can intrude. Next, in step 56, it is determined whether it is possible to change the lane of the host vehicle 1 from the overtaking lane to the driving lane. In this case, when the driving lane space 40 into which the host vehicle 1 can intrude is detected in the driving lane in front of the host vehicle 1, it is determined that it is possible to change the lane of the host vehicle 1 from the overtaking lane to the driving lane. When the driving lane space 40 into which the host vehicle 1 can intrude is not detected, it is determined that it is impossible to change the lane of the host vehicle 1 from the overtaking lane to the driving lane, and the processing cycle ends.

[0025] In step 56, when it is determined that it is possible to change the lane of the host vehicle 1 from the overtaking lane to the driving lane, the process proceeds to step 57, and the notification device 22 notifies the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1, thereby prompting the driver of the host vehicle 1 to change the lane to the driving lane.

[0026] On the other hand, in step 51, when it is determined that the road on which the host vehicle 1 is currently traveling does not have multiple lanes, or in step 52, when it is determined that the host vehicle 1 is not currently traveling in the overtaking lane, or in step 54, when it is determined that the following vehicle 2 is not approaching the host vehicle 1, the process proceeds to step 58, and the notification device 22 stops notifying the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1, thereby stopping prompting the driver of the host vehicle 1 to change the lane to the driving lane. Therefore, when the host vehicle 1 changes the lane from the overtaking lane to the driving lane, in step 52, it is determined that the host vehicle 1 is not currently traveling in the overtaking lane, or in step 54, it is determined that the following vehicle 2 is not approaching the host vehicle 1, so the notification device 22 stops notifying the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1.

[0027] As described above, the following-vehicle approach notification device according to the present invention includes a detection device 18 capable of detecting the approach of a following vehicle 2 to the host vehicle 1, a notification device 22 for notifying the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1, and a processor 15. In the present invention, this processor 15 acquires information regarding the lane of the road on which the host vehicle 1 is traveling, and when the approach of the following vehicle 2 to the host vehicle 1 is detected by the detection device 18 while traveling in the passing lane 35a, it determines whether or not the host vehicle 1 can change lanes from the passing lane 35a to the driving lane 34a. At this time, if it is determined that the host vehicle 1 can change lanes from the passing lane 35a to the driving lane 34a, the notification device 22 notifies the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1, and if it is determined that the host vehicle 1 cannot change lanes from the passing lane 35a to the driving lane 34a, the notification device 22 cancels notifying the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1.

[0028] In this case, in the embodiment according to the present invention, the detection device 18 can detect the presence of a driving lane space 40 into which the host vehicle 1 can intrude, and when the approach of the following vehicle 2 to the host vehicle 1 is detected by the detection device 18 while traveling in the passing lane 35a, the processor 15 determines that the host vehicle 1 can change lanes from the passing lane 35a to the driving lane 34a if the detection device 18 detects the presence of a driving lane space 40 into which the host vehicle 1 can intrude.

[0029] Note that, in the embodiment according to the present invention, as can be seen from the flowchart shown in FIG. 5, even when it is determined in step 54 that the following vehicle 2 has approached the host vehicle 1, if it is determined in step 56 that it is impossible to change the lane of the host vehicle 1 from the passing lane 35a to the driving lane 34a, notifying the driver of the host vehicle 1 of the approach of the following vehicle 2 to the host vehicle 1 is canceled, and when it is determined in step 56 that it is possible to change the lane of the host vehicle 1 from the passing lane 35a to the driving lane 34a, the driver of the host vehicle 1 is notified of the approach of the following vehicle 2 to the host vehicle 1.

[0030] That is to say, in other words, in the embodiment according to the present invention, when the processor 15 is traveling in the overtaking lane 35a, even if the detection device 18 continuously detects the approach of the following vehicle 2 to the host vehicle 1, if the detection device 18 does not detect the existence of the travel lane space 40 into which the host vehicle 1 can enter, the notification device 22 continues to cancel the notification to the driver of the host vehicle 1 about the approach of the following vehicle 2 to the host vehicle 1, and when the detection device 18 detects the existence of the travel lane space 40 into which the host vehicle 1 can enter, the notification device 22 notifies the driver of the host vehicle 1 about the approach of the following vehicle 2 to the host vehicle 1.

[0031] When the following vehicle 2 approaches the host vehicle 1 while traveling in the overtaking lane 35a and the following vehicle 2 is performing a harassing operation on the host vehicle 1, it is highly likely that the driver of the host vehicle 1 is getting impatient. At this time, even though it is impossible for the host vehicle 1 to change lanes, if the driver of the host vehicle 1 is notified about the approach of the following vehicle 2 to the host vehicle 1, it may cause the driver of the host vehicle 1 to become even more impatient. In this embodiment, as described above, when it is impossible for the host vehicle 1 to change lanes, the notification to the driver of the host vehicle 1 about the approach of the following vehicle 2 to the host vehicle 1 is continuously cancelled, so that it is possible to avoid causing the driver of the host vehicle 1 to become highly impatient.

[0032] By the way, when the following vehicle 2 approaches the host vehicle 1 while traveling in the overtaking lane 35a, in the case where it is determined that the host vehicle 1 can change lanes from the overtaking lane 35a to the travel lane 34a, when the driver of the host vehicle 1 recognizes the approach of the following vehicle 2 and the travel lane space 40 into which the host vehicle 1 can enter, compared with when the driver of the host vehicle 1 does not recognize the approach of the following vehicle 2 and the travel lane space 40 into which the host vehicle 1 can enter, it is preferable to change the approach notification method of the following vehicle 2 to the driver of the host vehicle 1 to an approach notification method that reduces the degree of impatience caused to the driver. Therefore, in another embodiment according to the present invention, the approach notification method of the following vehicle 2 to the driver of the host vehicle 1 is changed according to whether the driver of the host vehicle 1 recognizes the approach of the following vehicle 2 and the travel lane space 40 into which the host vehicle 1 can enter.

[0033] Next, with reference to FIG. 6, another embodiment according to the present invention will be described. Note that FIG. 6 shows a view when looking forward from the interior of the host vehicle 1. In this another embodiment, based on the detection result of the line-of-sight detection device 9 (FIG. 1) installed in the vehicle interior, it is determined whether the driver of the host vehicle 1 recognizes the approach of the following vehicle 2 and the travel lane space 40 into which the host vehicle 1 can intrude. As described above, this line-of-sight detection device 9 includes, for example, an infrared LED that irradiates infrared rays onto the driver's eyeball and an infrared camera that detects the reflected light of the infrared rays on the cornea, and can detect the direction of the driver's line of sight from the reflected light of the infrared rays on the cornea.

[0034] For example, when the line-of-sight detection device 9 detects that the direction of the driver's line of sight is the rearview mirror 41 that captures the rear of the host vehicle 1, it can be determined that the driver recognizes the approach of the following vehicle 2. Further, when the line-of-sight detection device 9 detects that the direction of the driver's line of sight is the portion surrounded by the broken line through the front window 42 of the host vehicle 1, that is, when it is detected that it is the travel lane space 40 into which the host vehicle 1 can intrude, it can be determined that the driver recognizes the travel lane space 40 into which the host vehicle 1 can intrude. Therefore, in an example according to the present invention, when the line-of-sight detection device 9 detects that the direction of the driver's line of sight is the rearview mirror 41 and the travel lane space 40, it is determined that the driver recognizes the approach of the following vehicle 2 and the travel lane space 40 into which the host vehicle 1 can intrude.

[0035] Also, as another example, when the line-of-sight detection device 9 detects that the number of times of the line of sight directed at the interior mirror 41 is equal to or more than a certain number of times, it is determined that the driver recognizes the approach of the following vehicle 2. When it is detected that the number of times of the line of sight directed at the driving lane space 40 is equal to or more than a certain number of times, or when it is detected that the time during which the line of sight is directed at the driving lane space 40 is equal to or more than a certain time, it is determined that the driver recognizes the driving lane space 40 into which the host vehicle 1 can enter. Also, when changing lanes, it is considered that the driver of the host vehicle 1 checks the side mirror 43 and, in some cases, also checks the side mirror 44. Therefore, in addition to the interior mirror 41 and the driving lane space 40, when the line-of-sight detection device 9 detects that the driver has checked the side mirror 43 and, in some cases, has checked the side mirrors 43 and 44, it is determined that the driver recognizes the approach of the following vehicle 2 and the driving lane space 40 into which the host vehicle 1 can enter.

[0036] FIG. 7 shows a routine for executing the above-described another embodiment. This routine is also executed by an interrupt at every certain time within the electronic control unit 13 of the host vehicle 1. Note that steps 50, 51, 52, 53, 54, 55, 56, 57, 58 in the routine shown in FIG. 7 are the same as steps 50, 51, 52, 53, 54, 55, 56, 57, 58 in the routine shown in FIG. 5, and the difference between the routine shown in FIG. 7 and the routine shown in FIG. 5 is that only steps 55a, 56a, 57a are added in the routine shown in FIG. 7. Therefore, the description from step 50 to step 55 is omitted, and the description starts from step 55a.

[0037] Referring to FIG. 7, when it is determined in step 54 that the following vehicle 2 has approached the host vehicle 1, and when in step 55, a travel lane space 40 in which the host vehicle 1 can enter is detected, in step 55a, the direction of the driver's line of sight is detected by the line-of-sight detection device 9. The detection of the direction of the driver's line of sight is repeatedly performed every interrupt time as long as it is determined in step 54 that the following vehicle 2 has approached the host vehicle 1. The detection result of the direction of the driver's line of sight is stored in the memory 16. Next, when it is determined in step 56 that the host vehicle 1 can change lanes from the overtaking lane to the travel lane, it proceeds to step 56a, and based on the detection result of the direction of the driver's line of sight stored in the memory 16, it is determined whether the driver is aware of the surrounding situation, that is, whether the driver is aware of the approach of the following vehicle 2 and the travel lane space 40 in which the host vehicle 1 can enter.

[0038] In step 56a, when it is determined that the driver is not aware of the approach of the following vehicle 2 and the travel lane space 40 in which the host vehicle 1 can enter, it proceeds to step 57, and the approach of the following vehicle 2 to the host vehicle 1 is notified to the driver of the host vehicle 1 by the notification device 22, whereby the driver of the host vehicle 1 is urged to change lanes to the travel lane. At this time, the notification is performed in the same manner as the method of notifying the driver of the approach of the following vehicle 2 in step 57 of the routine shown in FIG. 5. On the other hand, in step 56a, when it is determined that the driver is aware of the approach of the following vehicle 2 and the travel lane space 40 in which the host vehicle 1 can enter, it proceeds to step 57a, and the approach of the following vehicle 2 to the host vehicle 1 is notified to the driver of the host vehicle 1 by the notification device 22, whereby the driver of the host vehicle 1 is urged to change lanes to the travel lane. At this time, the notification is performed by an approach notification method that reduces the degree of anxiety caused to the driver as compared with the method of notifying the driver of the approach of the following vehicle 2 in step 57 of the routine shown in FIG. 5. That is, the notification method to the driver is changed.

[0039] Thus, in this another embodiment, when the approaching of the following vehicle 2 to the host vehicle 1 is detected by the detection device 18 while the host vehicle 1 is traveling in the overtaking lane 35a, if it is determined that the host vehicle 1 can change lanes from the overtaking lane 35a to the driving lane 34a, it is determined whether the driver of the host vehicle 1 recognizes the approaching of the following vehicle 2 and the driving lane space 40 into which the host vehicle 1 can intrude. According to the determination result, the method of notifying the driver of the host vehicle 1 of the approaching of the following vehicle 2 to the host vehicle 1 is changed.

[0040] In this case, in this another embodiment, as described above, the notification of the approaching of the following vehicle 2 to the host vehicle 1 includes urging the host vehicle 1 to change lanes to the driving lane 34a by at least one of text display, voice, or sound. According to this determination result, the content of the text display, the content of the voice, the tone color of the sound, the display timing of the text display, the generation timing of the voice, or the generation timing of the sound is changed. For example, when the driver of the host vehicle 1 recognizes the approaching of the following vehicle 2 and the driving lane space 40 into which the host vehicle 1 can intrude, compared with when the driver of the host vehicle 1 does not recognize the approaching of the following vehicle 2 and the driving lane space 40 into which the host vehicle 1 can intrude, the tone color of the buzzer is changed to a gentle tone color, or the display timing of the text display, the generation timing of the voice, or the generation timing of the sound is delayed by 1 second to 2 seconds.

Explanation of Signs

[0041] 1 Host vehicle 2 Following vehicle 15 Processor 18 Detection device 23 Notification device 34a Driving lane 35a Overtaking lane 40 Driving lane space

Claims

Claim 1 A detection device capable of detecting the approach of a following vehicle to the host vehicle, a notification device for notifying the driver of the host vehicle of the approach of a vehicle behind the host vehicle, and a processor, wherein the processor acquires information regarding the lane of the road on which the host vehicle is traveling, when the approach of a following vehicle to the host vehicle is detected by the detection device while the host vehicle is traveling in the overtaking lane, determines whether the host vehicle can change lanes from the overtaking lane to the driving lane, when it is determined that the host vehicle can change lanes from the overtaking lane to the driving lane, causes the notification device to notify the driver of the host vehicle of the approach of the following vehicle to the host vehicle, and a following vehicle approach notification device that cancels the notification by the notification device to the driver of the host vehicle of the approach of the following vehicle to the host vehicle when it is determined that the host vehicle cannot change lanes from the overtaking lane to the driving lane. Claim 2 The detection device is capable of detecting the presence of a driving lane space into which the host vehicle can intrude, and when the approach of a following vehicle to the host vehicle is detected by the detection device while the host vehicle is traveling in the overtaking lane, the processor determines that the host vehicle can change lanes from the overtaking lane to the driving lane when the detection device detects the presence of a driving lane space into which the host vehicle can intrude. The following vehicle approach notification device according to claim 1. Claim 3 Even when the approach of a following vehicle to the host vehicle continues to be detected by the detection device while the host vehicle is traveling in the overtaking lane, if the detection device does not detect the presence of a driving lane space into which the host vehicle can intrude, the processor continues to cancel the notification by the notification device to the driver of the host vehicle of the approach of the following vehicle to the host vehicle, and when the detection device detects the presence of a driving lane space into which the host vehicle can intrude, the processor causes the notification device to notify the driver of the host vehicle of the approach of the following vehicle to the host vehicle. The following vehicle approach notification device according to claim 2. Claim 4 The notification of the approach of a vehicle behind the host vehicle includes a prompt to change lanes to the driving lane of the host vehicle by at least one of text display, voice, and sound. The following vehicle approach notification device according to claim 1. Claim 5 When the processor determines that the host vehicle can change lanes from the passing lane to the driving lane when the approaching of a following vehicle to the host vehicle is detected by the detection device during driving in the passing lane, the processor determines whether the driver of the host vehicle is aware of the approaching of the following vehicle and the driving lane space into which the host vehicle can enter, and according to the determination result, changes the method of notifying the driver of the host vehicle of the approaching of the following vehicle. The following vehicle approaching notification device according to claim 1.

6. The notification of the approaching of the following vehicle to the host vehicle includes a prompt for changing lanes of the host vehicle by at least one of text display, voice or sound, and according to the determination result, the content of the text display, the content of the voice, the tone color of the sound, the display timing of the text display, the generation timing of the voice, or the generation timing of the sound is changed. The following vehicle approaching notification device according to claim 5.

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