Driving assistance device

Abstract

To provide a driving support device for reducing the possibility that a driver feels annoyed with an alarm by reducing the possibility that an unnecessary alarm is issued.SOLUTION: The driving assistance device can issue a warning when there is an intersection in front of the vehicle. When a condition that the intersection is a blind-spot intersection including an area that is a blind spot of the vehicle is satisfied, the driving assistance apparatus determines whether or not a human flow density condition that a human flow density representing the number of moving bodies crossing a present road on which the vehicle is traveling at the blind-spot intersection per predetermined unit time is equal to or more than a predetermined first threshold and equal to or less than a predetermined second threshold is satisfied, and when the human flow density condition is satisfied, the driving assistance apparatus issues the alarm.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a driving assistance device that can issue a warning when an intersection is present ahead of a vehicle. [Background technology]

[0002] Conventionally, there have been known driving assistance devices that issue a warning when an intersection is present ahead of a vehicle. For example, the driving assistance device described in Patent Document 1 (hereinafter referred to as the "conventional device") issues a warning when a moving object enters a blind spot due to an obstruction. Note that the obstruction is registered in advance in map data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-123691 Summary of the Invention

[0004] At intersections where pedestrian density, which represents the number of moving objects crossing the "road on which the vehicle is traveling" per unit time, is high, drivers are likely to be wary of moving objects jumping into their own lane. On the other hand, at intersections where pedestrian density is low, there is a low possibility of a moving object jumping into their own lane. If an alarm is issued under these circumstances, drivers are likely to find the alarm annoying.

[0005] Conventional devices issue warnings when a moving object enters a blind spot without using pedestrian flow density. This means that conventional devices may issue unnecessary warnings, which may be annoying to drivers.

[0006] The present invention has been made to address the above-mentioned problems. That is, one of the objects of the present invention is to provide a driving assistance device that reduces the possibility that an unnecessary warning will be issued, thereby reducing the possibility that the driver will find the warning annoying.

[0007] The driving assistance device of the present invention (hereinafter referred to as "the device of the present invention") is capable of issuing a warning when an intersection is present ahead of the vehicle. The device of the present invention comprises: If the condition that the intersection is a blind spot intersection that includes an area in the blind spot of the vehicle is met (step 315 "Yes", step 505 "Yes"), it is determined whether or not a pedestrian flow density condition is met, that is, the pedestrian flow density representing the number of moving objects crossing the road on which the vehicle is traveling at the blind spot intersection per predetermined unit time is equal to or greater than a predetermined first threshold and equal to or less than a predetermined second threshold (step 325, step 405, step 510), If the pedestrian flow density condition is met (step 325 "Yes", step 405 "Yes", step 510 "Yes"), the warning is issued (step 345, step 350, step 365, step 370). It is structured as follows.

[0008] At intersections where the pedestrian flow density condition is met, the driver is unlikely to pay attention to a moving object suddenly appearing, and there is a good chance that a moving object will suddenly appear into the vehicle's own lane. According to the device of the present invention, an alarm is issued when the pedestrian flow density condition is met, thereby reducing the possibility of an unnecessary alarm being issued and reducing the possibility that the driver will find the alarm annoying. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic system configuration diagram of a driving assistance device according to an embodiment of the present invention; [Figure 2] 1 is an explanatory diagram illustrating an outline of an operation of a driving assistance device according to an embodiment of the present invention; [Figure 3] 2 is a flowchart of a part of an intersection warning routine executed by a CPU of the ECU shown in FIG. 1. [Figure 4] 2 is a flowchart of a part of an intersection warning routine executed by a CPU of the ECU shown in FIG. 1. [Figure 5] 10 is a flowchart of a part of an intersection warning routine executed by a CPU of an ECU of a driving assistance device according to a first modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1, a driving assistance device 10 according to this embodiment (hereinafter referred to as "the device 10") is applied to a vehicle VA. The device 10 is communicably connected to a server 20 via a network.

[0011] The device 10 includes the components shown in FIG. 1. In this specification, "ECU 30" refers to an electronic control device that includes a microcomputer as its main component. The ECU 30 is also referred to as a control unit, a controller, and a computer. The microcomputer includes a CPU (processor), a ROM, a RAM, an interface, and the like. The functions realized by the ECU 30 may be realized by multiple ECUs.

[0012] The front camera 32 captures a front image by capturing an image of the scenery in front of the vehicle VA. The driver's seat camera 34 captures a driver's seat image by capturing an image of an area including the face of a driver sitting in the driver's seat of the vehicle VA.

[0013] The vehicle speed sensor 36 measures the vehicle speed Vs, which indicates the speed of the vehicle VA. The ECU 30 acquires the detected value of the vehicle speed sensor 36. The GNSS (Global Navigation Satellite System) receiver 38 receives signals from multiple artificial satellites and identifies the current position (latitude and longitude) of the vehicle VA based on the received signals. The DCM (Data Communication Module) 40 is an interface connected to a network. The vehicle VA transmits and receives data to and from the server 20 via the DCM 40. The storage device 42 has a map data storage unit 42a. The map data storage unit 42a stores map data relating to the position, shape, and gradient θ of a road.

[0014] The power train actuator 50 changes the driving force generated by a drive device (e.g., an internal combustion engine and / or an electric motor) of the vehicle VA. The brake actuator 52 changes the braking force applied to the vehicle VA. The display 54 displays a warning screen, which will be described later. The speaker 56 emits a warning sound, which will be described later.

[0015] The server 20 collects location history data that represents the location history of the smartphone 60. The server 20 acquires the pedestrian flow density Den and the average crossing speed Vc at the intersection based on the location history data. The pedestrian flow density Den and the average crossing speed Vc will be described in detail later.

[0016] (Overview of operation) When an intersection condition is met that a "blind spot intersection including an area that is in the blind spot of the vehicle VA" exists ahead of the vehicle VA, the device 10 determines whether a pedestrian flow density condition is met. The device 10 acquires the pedestrian flow density Den at a blind spot intersection from the server 20. If the pedestrian flow density Den is equal to or greater than a first threshold density Dth1 and equal to or less than a second threshold density Dth2, the device 10 determines that the pedestrian flow density condition is met and issues an alarm. Note that the second threshold density Dth2 is set to a value greater than the first threshold density Dth1.

[0017] The pedestrian flow density Den represents the number of moving objects crossing the own road HR at the intersection per unit time. The own road HR is the road on which the vehicle VA is traveling.

[0018] No warning is issued at blind spot intersections where the pedestrian flow density Den is less than the first threshold density Dth1, and at blind spot intersections where the pedestrian flow density Den is greater than the second threshold density Dth2. Therefore, the device 10 reduces the possibility of issuing unnecessary warnings, thereby reducing the possibility that the driver will find the warning annoying.

[0019] In the example shown in FIG. 2, buildings ST1 and ST2 exist on both sides of the intersection (on both the left and right sides as viewed from the current road HR), so the intersection condition is met. The device 10 acquires the pedestrian flow density Den at the intersection from the server 20. Specifically, the device acquires the pedestrian flow density Den1 in the crossing direction CD1 in which a moving object crosses the current road HR at the intersection, and the pedestrian flow density Den2 in the crossing direction CD2. The pedestrian flow density condition is met when at least one of the pedestrian flow densities Den1 and Den2 is equal to or greater than the first threshold density Dth1 and equal to or less than the second threshold density Dth2. When the pedestrian flow density condition is met, the device 10 issues an alarm.

[0020] The server 20 newly collects data from the smartphone 60 every time a predetermined unit time elapses, and acquires the latest "people flow densities Den1 and Den2 and average crossing speeds Vc1 and Vc2" at the intersection.

[0021] (Specific operation) The CPU of the ECU 30 of the present device 10 executes the routine shown in the flowcharts of FIGS. 3 and 4 every time a predetermined time period elapses.

[0022] <Intersection warning routine> When an appropriate time arrives, the CPU starts processing from step 300 in Fig. 3. Next, in step 305, it is determined whether or not an intersection exists ahead of the vehicle VA. As an example, the CPU determines that an intersection exists ahead of the vehicle VA if "images of objects for recognizing the intersection (e.g., traffic lights, intersection signs, intersection road markings, etc.)" exist in the forward image. Images of objects for recognizing the intersection are registered in advance.

[0023] If an intersection is present ahead of the vehicle VA, the CPU determines "No" in step 305, and the process proceeds to step 310. In step 310, the CPU determines whether the arrival time Tin, which represents the time it takes for the vehicle VA to arrive at the intersection, is equal to or greater than the first threshold time Tth1 and equal to or less than the second threshold time Tth2. The CPU obtains the arrival time Tin by dividing the distance from the vehicle VA to the intersection by the vehicle speed Vs.

[0024] If the arrival time Tin is equal to or greater than the first threshold time Tth1 and equal to or less than the second threshold time Tth2, the CPU determines "Yes" in step 310 and the process proceeds to step 315.

[0025] In step 315, the CPU determines whether there are blind spot areas on both sides of the own road HR at the intersection that are blind spots for the vehicle. As an example, the CPU has previously learned images for identifying three-dimensional objects that create blind spot areas, and if the three-dimensional objects are detected on both sides of the own road HR near the intersection based on the forward image, it determines that blind spot areas exist on both sides.

[0026] If there are blind spots on both sides of the intersection, the intersection condition is met. In this case, the CPU determines "Yes" in step 315 and executes steps 320 and 325.

[0027] Step 320: The CPU acquires from the server 20 the pedestrian flow densities Den1 and Den2 of the blind spot intersections that satisfy the intersection conditions. Step 325: The CPU determines whether both of the pedestrian flow densities Den1 and Den2 are equal to or greater than the first threshold density Dth1 and equal to or less than the second threshold density Dth2.

[0028] If both the pedestrian flow densities Den1 and Den2 are equal to or greater than the first threshold density Dth1 and equal to or less than the second threshold density Dth2, the pedestrian flow density condition is met. In this case, the CPU determines "Yes" in step 325 and executes steps 330 and 335.

[0029] Step 330: The CPU refers to the map data and obtains the gradient θ of the intersecting road IR (see FIG. 2) that intersects with the own road HR at the blind spot intersection. Specifically, the CPU identifies the blind spot intersection and the cross road IR on the map data based on the current position of the vehicle VA identified by the GNSS receiver 38, and obtains the gradient θ of the cross road IR at the blind spot intersection. Step 335: The CPU determines whether the magnitude (|θ|) of the gradient θ is equal to or greater than the threshold gradient θth.

[0030] If the magnitude of the gradient θ (|θ|) is equal to or greater than the threshold gradient θth, the gradient of either of the crossing directions CD1 and CD2 that satisfy the pedestrian flow density condition becomes a downward gradient, and the magnitude of the gradient θ (|θ|) is equal to or greater than the threshold gradient θth, so the gradient condition is satisfied. When the gradient condition is satisfied, there is a high possibility that a moving object will cross the road HR at a relatively high speed. Furthermore, since such a moving object is crossing a downward gradient, it cannot stop immediately. Therefore, there is a high possibility that the vehicle VA will come into contact with such a moving object.

[0031] If the gradient condition is met, the CPU determines "Yes" in step 335, and the process proceeds to step 340. In step 340, the CPU determines, based on the driver's seat image, whether the driver is looking in the direction of the blind spot intersection.

[0032] If the driver is not looking toward the blind spot intersection, the CPU determines "No" in step 340 and executes step 345. In step 345, the CPU issues a first warning and performs deceleration control to decelerate the vehicle VA at a predetermined deceleration. Thereafter, the process proceeds to step 395, where the CPU temporarily ends this routine.

[0033] In the first warning, the CPU displays a first warning screen on the display 54 and sounds a first warning sound from the speaker 56. The first warning screen is a screen for notifying the driver of the risk of a moving object jumping out from the blind spot area. The frame of the first warning screen is red. The first warning sound is an audio message for notifying the driver of the risk of a moving object jumping out from the blind spot area.

[0034] In the deceleration control, the CPU controls the power train actuator 50 and the brake actuator 52 so that the acceleration of the vehicle VA coincides with a predetermined deceleration.

[0035] If the driver is looking toward the blind spot intersection when the process proceeds to step 340, the CPU determines "Yes" in step 340 and executes step 350. In step 350, the CPU issues a first warning. Thereafter, the process proceeds to step 395, and the CPU temporarily ends this routine.

[0036] If the magnitude (|θ|) of the gradient θ is less than the threshold gradient θth when the process proceeds to step 335, the gradient condition is not met. In this case, the CPU determines “No” in step 335 and executes steps 355 and 360.

[0037] Step 355: The CPU acquires the average crossing speed Vc of the blind spot intersection from the server 20. The average crossing speed Vc is the average speed of moving objects crossing the own road HR at the blind spot intersection per predetermined unit time. In step 355, the CPU acquires the average crossing speed Vc1 in the crossing direction CD1 and the average crossing speed Vc2 in the crossing direction CD2 from the server 20.

[0038] Step 360: The CPU determines whether the magnitude (|Vc|) of the average crossing speed Vc is greater than or equal to the threshold speed Vcth.

[0039] When the magnitude (|Vc|) of the average crossing speed Vc is equal to or greater than the threshold speed Vcth, the crossing speed condition is met. When the crossing speed condition is met, there is a high possibility that a moving object will cross the road HR at a relatively high speed. For such a moving object, the vehicle VA is more likely to come into contact with another moving object crossing the road HR. Because the gradient condition is not met, such a moving object is not crossing a steep downward gradient. Such a moving object is more likely to stop than a moving object crossing a steep downward gradient. For this reason, there is a higher possibility that the vehicle VA will come into contact with a moving object when the gradient condition is met than when the gradient condition is not met.

[0040] If the crossing speed condition is met, the CPU determines "Yes" in step 360, and the process proceeds to step 365. In step 365, the CPU issues a second warning. The warning strength of the second warning is weaker than that of the first warning. Thereafter, the process proceeds to step 395, and the CPU temporarily ends this routine.

[0041] In the second alarm, the CPU displays a second alarm screen on the display and sounds a second alarm sound from the speaker 56. The second alarm screen is the same as the first alarm screen, but the frame of the second alarm screen is yellow. The second alarm sound has the same voice message as the first alarm sound, but the volume of the second alarm sound is smaller than that of the first alarm sound.

[0042] If the magnitude (|Vc|) of the average crossing speed Vc is less than the threshold speed Vcth when the process proceeds to step 360, the crossing speed condition is not met. In this case, the CPU determines "No" in step 360, and the process proceeds to step 370. In step 370, the CPU issues a third warning. The warning strength of the third warning is weaker than the second warning. In other words, the warning strength of the second warning is stronger than the third warning.

[0043] In the third alarm, the CPU displays a third alarm screen on the display and sounds a third alarm sound from the speaker 56. The third alarm screen is the same as the first and second alarm screens, but does not have a frame. The third alarm sound is the same audio message as the first and second alarm sounds, but the volume of the third alarm sound is smaller than that of the second alarm sound.

[0044] If there is no intersection ahead of the vehicle VA when the process proceeds to step 305, the intersection condition is not met. In this case, the CPU determines "No" in step 305, and the process proceeds to step 395, where the CPU temporarily ends this routine.

[0045] If the arrival time Tin is less than the first threshold time Tth1 or greater than the second threshold time Tth2 when the process proceeds to step 310, the intersection condition is not met. In this case, the CPU determines "No" in step 310, and the process proceeds to step 395, where the CPU temporarily ends this routine.

[0046] If the blind spot area exists only on the one side of the intersection or if there are no blind spot areas on either side of the intersection when the process proceeds to step 315, the intersection condition is not met. In this case, the CPU determines "No" in step 315, and the process proceeds to step 395, where the CPU temporarily ends this routine.

[0047] When the process proceeds to step 325, if at least one of the pedestrian flow densities Den1 and Den2 is less than the first threshold density Dth1 or greater than the second threshold density Dth, the CPU determines "No" in step 325, and the process proceeds to step 405 shown in Fig. 4. In Fig. 4, the same processes as those in Fig. 3 are assigned the same reference numerals, and their explanations will be omitted.

[0048] In step 405, the CPU determines whether or not one of the pedestrian flow densities Den1 and Den2 is equal to or greater than the first threshold density Dth1 and equal to or less than the second threshold density Dth2.

[0049] If either the pedestrian flow densities Den1 and Den2 is equal to or greater than the first threshold density Dth1 and equal to or less than the second threshold density Dth2, the CPU determines "Yes" in step 405. Then, the process proceeds to step 330 shown in Fig. 4, where the CPU obtains the gradient θ of the intersecting road IR.

[0050] Processing then proceeds to step 410, where the CPU determines whether the gradient θ is a downward gradient when viewed from the crossing direction of the pedestrian flow density Den that satisfies the pedestrian flow density condition among the crossing directions CD1 and CD2 (hereinafter referred to as the "established crossing direction").

[0051] If the gradient θ is a downward gradient as viewed from the crossing direction, the CPU determines "Yes" in step 410, and the process proceeds to step 335 shown in Figure 4. If the magnitude of the gradient θ (|θ|) is equal to or greater than the threshold gradient θth, the gradient condition is met. In this case, the CPU determines "Yes" in step 335 shown in Figure 4, and the process proceeds to step 340 shown in Figure 3.

[0052] If the gradient θ is an uphill gradient as viewed from the crosswise direction when the process proceeds to step 410, the gradient condition is not met. In this case, the CPU determines "No" at step 410, and the process proceeds to step 415. Also, if the magnitude of the gradient θ (|θ|) is less than the threshold gradient θth when the process proceeds to step 335 shown in FIG. 4, the gradient condition is not met. In this case, the CPU determines "No" at step 335 shown in FIG. 4, and the process proceeds to step 415.

[0053] In step 415, the CPU acquires the average crossing speed Vc of the established crossing direction. Then, in 360 shown in FIG. 4, the CPU determines whether the magnitude (|Vc|) of the average crossing speed Vc of the established crossing direction is equal to or greater than the threshold speed Vcth.

[0054] If the magnitude (|Vc|) of the average crossing speed Vc in the established crossing direction is equal to or greater than the threshold speed Vcth, the crossing speed condition is met. In this case, the CPU determines "Yes" at step 360 shown in FIG. 4, and the process proceeds to step 365 shown in FIG. 3. On the other hand, if the magnitude (|Vc|) of the average crossing speed Vc in the established crossing direction is less than the threshold speed Vcth, the crossing speed condition is not met. In this case, the CPU determines "No" at step 360 shown in FIG. 4, and the process proceeds to step 370 shown in FIG. 3.

[0055] If the pedestrian flow density condition is not met when the process proceeds to step 405 and both of the pedestrian flow densities Den1 and Den2 are less than the first threshold density Dth1 or greater than the second threshold density Dth2, the CPU determines "No" in step 405, and the process proceeds to step 395 shown in FIG. 3, where the CPU temporarily ends this routine.

[0056] As described above, if the pedestrian flow density condition is met ("Yes" in step 325 shown in FIG. 3, "Yes" in step 405 shown in FIG. 4), the CPU issues one of the first to third warnings, and if the pedestrian flow density condition is not met ("No" in step 405 shown in FIG. 4), the CPU does not issue any warning. This reduces the possibility of unnecessary warnings being issued, thereby reducing the possibility that the driver will find the warnings annoying.

[0057] Furthermore, when the pedestrian flow density condition is met, the CPU determines whether the gradient condition is met (step 335 shown in FIG. 3, and steps 410 and 335 shown in FIG. 4). When the gradient condition is met, the CPU issues a first warning with a stronger warning intensity than when the gradient condition is not met (steps 345 and 350 shown in FIG. 3). When the gradient condition is met, the possibility that the moving object can be stopped is lower than when the gradient condition is not met, and therefore the possibility (contact probability) of the vehicle VA coming into contact with a moving object increases. For this reason, the warning is issued with a warning intensity according to the contact probability. This reduces the contact probability and also reduces the possibility that the driver will find the warning annoying.

[0058] Furthermore, if the gradient condition is not met, the CPU determines whether the crossing speed condition is met (step 360 shown in FIGS. 3 and 4). If the crossing speed condition is met, the CPU issues a second warning with a stronger warning intensity than when the crossing speed condition is not met (step 365 shown in FIG. 3). If the crossing speed condition is met, there is a higher possibility that the moving object will cross at a faster speed than when the crossing speed condition is not met, and therefore the possibility of contact increases. For this reason, the warning is issued with a warning intensity according to the possibility of contact. This reduces the possibility of contact and also reduces the possibility that the driver will find the warning annoying.

[0059] Furthermore, when the gradient condition is met, the CPU performs deceleration control if the driver is not looking toward the blind spot intersection ("No" in step 340 shown in FIG. 3). This changes the behavior of the vehicle VA, making it more likely that the driver will look toward the blind spot intersection. Furthermore, the vehicle speed Vs can be reduced.

[0060] (First Modification) In the above embodiment, the intersection condition is met when there are blind spot areas on both sides of the intersection, but in this modification, the intersection condition is met when there is a blind spot area on at least one side of the intersection.

[0061] In this modification, if there are no blind spot areas on both sides of the intersection when the process proceeds to step 315 shown in Fig. 3, the CPU determines "No" in step 315, and the process proceeds to step 505 shown in Fig. 5. In step 505, it is determined whether or not there is a blind spot area on one side of the intersection (either the left or right side of the intersection as viewed from the own road HR).

[0062] If a blind spot area exists on one side of the intersection, the CPU determines "Yes" in step 505, and the process proceeds to step 510. In step 510, the CPU determines whether the pedestrian flow density Den in the blind spot direction is equal to or greater than a first threshold density Dth1 and equal to or less than a second threshold density Dth2. The blind spot direction is the crossing direction from the side of the intersection where the blind spot area exists to the side where no blind spot area exists.

[0063] If the pedestrian flow density Den in the blind spot direction is equal to or greater than the first threshold density Dth1 and equal to or less than the second threshold density Dth2, the pedestrian flow density condition is met. In this case, the CPU determines "Yes" in step 510 and executes steps 515 and 520.

[0064] Step 515: The CPU obtains the gradient θ of the blind spot direction from the map data. Step 520: The CPU determines whether the gradient θ is a downward gradient when viewed from the blind spot direction.

[0065] If the gradient θ is a downward gradient as viewed from the blind spot direction, the CPU determines "Yes" in step 520, and the process proceeds to step 335 shown in Fig. 5. If the magnitude of the gradient θ (|θ|) is equal to or greater than the threshold gradient θth, the gradient condition is met, the CPU determines "Yes" in step 335 shown in Fig. 5, and the process proceeds to step 340 shown in Fig. 3.

[0066] If the gradient θ is an uphill gradient as viewed from the blind spot direction, the gradient condition is not met. In this case, the CPU determines "No" at step 520, and the process proceeds to step 525. If the magnitude of the gradient θ (|θ|) is less than the threshold gradient θth, the gradient condition is not met. In this case, the CPU determines "No" at step 335 shown in FIG. 5, and the process proceeds to step 525.

[0067] In step 525, the CPU obtains the average crossing speed Vc in the blind spot direction of the blind spot intersection from the server 20, and the process proceeds to step 360 shown in Figure 5. If the magnitude (|Vc|) of the average crossing speed Vc in the blind spot direction is equal to or greater than the threshold speed Vcth, the CPU determines "Yes" in step 360 shown in Figure 5, and the process proceeds to step 365 shown in Figure 3. If the magnitude (|Vc|) of the average crossing speed Vc in the blind spot direction is less than the threshold speed Vcth, the CPU determines "No" in step 360 shown in Figure 5, and the process proceeds to step 370 shown in Figure 3.

[0068] If there is no blind spot area when the process proceeds to step 505 shown in Figure 5, the intersection condition is not met. In this case, the CPU determines "No" at step 505, and the process proceeds to step 395 shown in Figure 3. If the pedestrian flow density Den in the blind spot direction is less than the first threshold density Dth1 or greater than the second threshold density Dth2 when the process proceeds to step 510 shown in Figure 5, the pedestrian flow density condition is not met. In this case, the CPU determines "No" at step 510, and the process proceeds to step 395 shown in Figure 3.

[0069] According to this modification, when a blind spot exists on only one side of an intersection and the pedestrian flow density Den in the blind spot direction satisfies the pedestrian flow density condition, an alarm is issued. Because there is a high probability that a moving object emerging from the non-blind spot side will be visible to the driver, no alarm is issued even if the pedestrian flow density from the non-blind spot side satisfies the pedestrian flow density condition. This reduces the likelihood that the driver will find the alarm annoying.

[0070] (Second Modification) If neither the pedestrian flow densities Den1 nor Den2 satisfy the pedestrian flow density condition (step 405 “No” shown in FIG. 4 ), the CPU may issue a fourth alarm if at least one of the pedestrian flow densities Den1 and Den2 is greater than the second threshold density Dth2. The alarm strength of the fourth alarm is weaker than the third alarm.

[0071] (Third Modification) Blind spot intersections may be registered in advance in map data, and the CPU may determine whether or not a blind spot intersection exists based on the current position of the vehicle VA identified by the GNSS receiver 38 and the map data.

[0072] (Fourth Modification) The warning intensity of the warning screen may be changed by the blinking period of the warning screen. The shorter the blinking period, the stronger the warning intensity. The alarm sound is not limited to a voice message. For example, the alarm sound may be generated in such a manner that a predetermined continuous sound is generated for a predetermined continuous time, followed by a predetermined silence time without sound generation, and then the continuous sound is generated for the continuous time after the silence time has elapsed. Note that the shorter the silence time, the stronger the alarm intensity. The warning may be at least one of displaying a warning screen and emitting a warning sound.

[0073] The device 10 can be applied to vehicles such as internal combustion engine vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles. Furthermore, the device 10 can also be applied to autonomous vehicles. [Explanation of symbols]

[0074] 10...driving assistance device, 20...server, 30...ECU, 32...front camera, 34...driver's seat camera, 50...power train actuator, 52...brake actuator, 54...display, 56...speaker

Claims

1. A driving assistance device capable of issuing a warning when an intersection is present ahead of a vehicle, The driving assistance device If the condition that the intersection is a blind spot intersection that includes an area that is a blind spot for the vehicle is met, determine whether or not a pedestrian flow density condition is met, where the pedestrian flow density, which represents the number of moving objects crossing the road on which the vehicle is traveling at the blind spot intersection per predetermined unit time, is equal to or greater than a predetermined first threshold value and equal to or less than a predetermined second threshold value; When the pedestrian flow density condition is met, the warning is issued. A driving assistance device configured as follows.

2. The driving assistance device according to claim 1, The pedestrian flow density is acquired for each direction in which the moving object crosses the road; The driving assistance device If the pedestrian flow density condition is satisfied, it is determined whether or not a gradient condition is satisfied in which the gradient in the transverse direction that satisfied the pedestrian flow density condition is a downward gradient and the magnitude of the gradient is equal to or greater than a threshold gradient; The strength of the warning when the gradient condition is met is made stronger than when the gradient condition is not met. A driving assistance device configured as follows.

3. The driving assistance device according to claim 2, The driving assistance device If the gradient condition is not satisfied, it is determined whether a crossing speed condition is satisfied, that is, whether the average crossing speed in the crossing direction that satisfied the pedestrian flow density condition is equal to or greater than a threshold speed; The intensity of the warning when the crossing speed condition is met is set to be stronger than when the crossing speed condition is not met. A driving assistance device configured as follows.

4. The driving assistance device according to claim 1, the driving assistance device is configured to execute deceleration control to decelerate the vehicle when the pedestrian flow density condition is met and the driver is not looking in the direction of the blind spot intersection; Driving assistance device.

Images