Driving assistance device, vehicle, driving assistance method, and recording medium

Abstract

The driving assistance device includes: a surrounding sensor that acquires surrounding information; and a control unit that executes driving assistance control including at least one of pre-turn deceleration assistance control and pre-turn warning control when a prescribed execution condition is satisfied, the control unit determining whether or not the execution condition is satisfied at a first point in time based on whether or not a specific condition is satisfied in which the type of a direction other than a straight-ahead direction included in a travelable direction of a first road arrow mark detected at the first point in time is reduced compared to the type of a direction other than a straight-ahead direction included in a travelable direction of second road arrow information already stored in a storage device at the first point in time, performs an overlay process in which the second road arrow information is overlaid with the first road arrow information and stored at the first point in time or a retention process in which the second road arrow information is retained at the first point in time, and determines whether or not the execution condition is satisfied at the first point in time based on road arrow information after the overlay process or the retention process is performed.

Description

Technical Field

[0001] The present invention relates to a driving assistance device, vehicle, driving assistance method, and recording medium capable of performing driving assistance controls including pre-turn deceleration assist control and / or pre-turn warning control, wherein the pre-turn deceleration assist control assists the vehicle in decelerating before turning left or right at an intersection, and the pre-turn warning control warns the driver of the vehicle before turning left or right at an intersection. Background Technology

[0002] In recent years, research has led to the development of driver assistance control technologies that assist in decelerating a vehicle to a predetermined target speed before making left or right turns at intersections. Driver assistance control includes at least one of left / right turn deceleration assist control and left / right turn warning control. Left / right turn deceleration assist control automatically applies braking force to the vehicle in a manner that matches the vehicle's deceleration to a target deceleration, thereby assisting in decelerating the vehicle before making left or right turns at intersections. Left / right turn warning control alerts the driver, thereby prompting the driver to decelerate before making left or right turns at intersections.

[0003] For example, Patent Document 1 discloses a driving assistance device (hereinafter referred to as "conventional device") configured to issue an alarm before the vehicle enters the intersection if the vehicle's speed exceeds a prescribed speed (the speed at which a vehicle can safely turn at the intersection) before it makes a left or right turn at the intersection.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2011-129013 Summary of the Invention

[0007] Conventional devices determine whether a vehicle intends to turn left or right at an intersection based on road arrow markings on the driving lane (the lane the vehicle is traveling in). Specifically, conventional devices determine a vehicle's intention to turn left or right if the road arrow markings on the driving lane detected by the camera device include right-turn arrows and / or left-turn arrows. Furthermore, in Patent Document 1, "camera device" and "road arrow markings" are described as "CCD camera" and "road markings," respectively.

[0008] Road arrow markings are arrow-shaped road markings that indicate the permissible direction of travel for a lane. Typically, multiple arrows are spaced apart along the lane's extension before an intersection. Road arrow markings can become blurred (faded) over time. If at least one right-turn (or left-turn) arrow on a road arrow marking becomes blurred due to age, the camera cannot recognize it. Consequently, conventional devices might interpret this as the vehicle not intending to turn right (or left), thus failing to issue a proper warning.

[0009] Additionally, depending on the intersection layout (e.g., intersections with pedestrian overpasses), the type of road arrow marking for the rightmost (or leftmost) lane may change from "straight arrow and right turn arrow (or left turn arrow)" to "straight arrow" along the direction of vehicle travel (see [reference]). Figure 6A In this situation, when the road arrow markings that are the target of the camera change from "straight arrow and right turn arrow (or left turn arrow)" to "straight arrow", the previous device would determine that the vehicle no longer intended to turn right (or left). Therefore, even if "the vehicle intended to turn left or right and the speed exceeded the prescribed speed", the alarm might stop.

[0010] In a configuration that "determines the vehicle's intention to turn left or right based on the type of road arrow markings identified by the camera, and executes driver assistance control (in the above example, left and right turn warning control) based on the intention", driver assistance control cannot be properly executed if the right turn arrow (or left turn arrow) of the road arrow markings is blurred, or if the type of road arrow markings changes from "straight arrow and right turn arrow (or left turn arrow)" to "straight arrow" along the vehicle's direction of travel.

[0011] This invention was made to address the aforementioned problems. Specifically, one objective of this invention is to provide a technology capable of appropriately performing driver assistance controls.

[0012] The driving assistance device based on the present invention (hereinafter also referred to as the "device of the present invention") includes:

[0013] Ambient sensors (11, 12) acquire road markings and intersection-related information present in the area ahead as ambient information, said area ahead being the area including the road surface in front of the vehicle (V); and

[0014] The control unit (10), having a storage device, is configured to execute, when predetermined execution conditions are met, including the detection of an intersection based on the surrounding information, a driver assistance control including at least one of left and right turn deceleration assist control and left and right turn warning control. The left and right turn deceleration assist control automatically applies braking force to the vehicle in a manner that makes the vehicle's deceleration consistent with a target deceleration, thereby assisting the vehicle in decelerating to a predetermined target speed before making a right or left turn at the detected intersection. The left and right turn warning control alerts the driver of the vehicle, thereby prompting the driver to decelerate before making a right or left turn at the detected intersection.

[0015] The control unit is configured to,

[0016] When an intersection (I1, I2) is detected based on the surrounding information, and a road surface arrow mark is detected on the lane (L1, L2) in which the vehicle is traveling, the system associates and stores the road surface arrow information, including the road surface arrow mark and the permissible direction of travel of the lane indicated by it, with the detected intersection in the storage device.

[0017] If, based on the surrounding information, any intersection is detected, and the road surface arrow mark detected at any first time point is designated as a first road surface arrow mark, the road surface arrow information of the first road surface arrow mark is designated as first road surface arrow information, and the road surface arrow information associated with the intersection detected at the first time point and already stored in the storage device is designated as second road surface arrow information, then it is determined whether the following specific condition is met: the specific condition is met if the number of types (t1) of directions other than the straight-ahead direction included in the travel direction of the driving lane indicated by the first road surface arrow mark is reduced compared to the number of types (t2) of directions other than the straight-ahead direction included in the travel direction of the driving lane included by the second road surface arrow information (step 840).

[0018] Based on whether the specific conditions are met, either a covering process is performed to cover the second road surface arrow information with the first road surface arrow information at the first time point and store it, or a retention process is performed to keep the second road surface arrow information at the first time point.

[0019] Based on the road surface arrow information after the coverage processing or the retention processing, it is determined whether the execution condition is met at the first time point.

[0020] In the device of the present invention, whether the execution condition is established is determined based on the road surface arrow information after the covering process or the holding process (i.e., the road surface arrow information stored in the storage device), rather than based on the road surface arrow information of the road surface arrow mark detected according to the surrounding information. Which of the covering process and the holding process is performed is determined based on whether a specific condition is established. The specific condition is established when the type t1 of the direction other than the straight-ahead direction of the travelable direction of the first road surface arrow mark detected at the first time point is less than the type t2 of the direction other than the straight-ahead direction included in the travelable direction of the driving lane included in the second road surface arrow information already stored in the storage device at the first time point.

[0021] In the case where the specific condition is not established (i.e., in the case where t1 = t2 or t1 > t2), the first road surface arrow information is equally accurate as the second road surface arrow information or is more likely to be more accurate than the second road surface arrow information. On the other hand, in the case where the specific condition is established (i.e., in the case where t1 < t2), the first road surface arrow information is less likely to have less information (less accurate than the second road surface arrow information). Therefore, by performing the covering process or the holding process based on whether the specific condition is established, it is possible to determine whether the execution condition is established at the first time point based on more accurate road surface arrow information. As a result, the determination accuracy of the execution condition is improved, and the driving assistance control can be appropriately executed.

[0022] In one aspect of the present invention,

[0023] the control unit (10) is configured to,

[0024] in the case where the specific condition is not established (step 840: no), perform the covering process (step 860),

[0025] in the case where the specific condition is established (step 840: yes), perform the holding process (step 850).

[0026] According to this configuration, it is possible to suppress the occurrence of interruption or inoperability of the driving assistance control in the case of a left or right turn intention at an intersection, and the driving assistance control can be appropriately executed.

[0027] In one aspect of the present invention,

[0028] the control unit (10) is configured to,

[0029] in the case where the specific condition is not established (step 840: no), perform the covering process (step 860),

[0030] in the case where the specific condition is established (step 840: yes),

[0031] When the control execution condition that is established when the driving assistance control is being executed is met (step 1210: Yes), the holding process is performed (step 850).

[0032] If the control execution condition is not met (step 1210: No), the overwrite process is performed (step 860).

[0033] Based on this configuration, it is possible to suppress unnecessary work of driver assistance control when there is an intention to change lanes, and to perform driver assistance control appropriately.

[0034] In one aspect of the invention,

[0035] The control unit (10) is configured to,

[0036] Multiple types of road arrow mark samples are pre-stored in a non-volatile storage device as a road arrow mark group.

[0037] If a road arrow mark is detected based on the surrounding information (step 810: Yes), select the road arrow mark that is most similar to the detected road arrow mark from the group of road arrow marks.

[0038] The similarity between the detected road arrow markings and the selected road arrow markings is calculated as the reliability of the detected road arrow markings.

[0039] If the reliability is less than the specified reliability threshold (step 1310: No), the holding process is performed.

[0040] According to this configuration, for example, if the road arrow markings become quite blurry due to deterioration over time, then maintenance processing is performed even if the reliability is less than the reliability threshold. Therefore, it is less likely that the road arrow information stored in the storage device will be overwritten by road arrow information with low reliability, thereby suppressing the decrease in the accuracy of the execution condition determination.

[0041] In one aspect of the invention,

[0042] It also includes a direction indicator switch (18(18R, 18L)) that can detect the operating status of the control (WL) operated by the driver of the vehicle to activate the direction indicator (20).

[0043] The control unit (10) is configured to,

[0044] When an intersection is detected based on the surrounding information, and the operating state of the operator detected by the direction indicator switch corresponds to the travelable direction of the driving lane indicated by the road surface arrow information stored in the storage device, the execution condition is determined to be met.

[0045] Based on this configuration, it is possible to appropriately determine whether there is an intention to turn left or right at an intersection, so that driving assistance control can be performed when there is a high probability of such an intention to turn left or right.

[0046] The vehicle based on the present invention is equipped with the device of the present invention.

[0047] The driving assistance method based on the present invention includes the following steps:

[0048] The surrounding sensors (11, 12) acquire road markings and intersection-related information existing in the area ahead as surrounding information, the area ahead being the area including the road surface in front of the vehicle (V);

[0049] If the specified execution conditions, including the detection of an intersection based on the surrounding information, are met, a driver assistance control is executed, including at least one of left and right turn deceleration assist control and left and right turn warning control. The left and right turn deceleration assist control automatically applies braking force to the vehicle in a manner that makes the vehicle's deceleration consistent with the target deceleration, thereby assisting the vehicle in decelerating to a specified target speed before making a right or left turn at the detected intersection. The left and right turn warning control alerts the driver of the vehicle, thereby prompting the driver to decelerate before making a right or left turn at the detected intersection.

[0050] When an intersection (I1, I2) is detected based on the surrounding information, and a road arrow mark is detected on the lane (L1, L2) in which the vehicle is traveling, the road arrow information, which includes the road arrow mark and the travel direction of the lane indicated by it, is associated with the detected intersection and stored in the storage device.

[0051] If any intersection is detected based on the surrounding information, and the road surface arrow mark detected at any first time point is designated as the first road surface arrow mark, the road surface arrow information of the first road surface arrow mark is designated as the first road surface arrow information, and the road surface arrow information associated with the intersection detected at the first time point and already stored in the storage device is designated as the second road surface arrow information, then it is determined whether the following specific condition is met: the specific condition is met when the number of directions other than the straight-ahead direction included in the travel direction of the driving lane indicated by the first road surface arrow mark (t1) is reduced compared to the number of directions other than the straight-ahead direction included in the travel direction of the driving lane included by the second road surface arrow information (t2) (step 840).

[0052] Based on whether the specific conditions are met, perform either a covering process (overlaying the second road surface arrow information with the first road surface arrow information at the first time point and storing it) or a holding process (keeping the second road surface arrow information at the first time point); and

[0053] Based on the road surface arrow information after the coverage processing or the retention processing, it is determined whether the execution condition is met at the first time point.

[0054] According to this driving assistance method, driving assistance control can be performed appropriately.

[0055] The computer-readable, non-transient recording medium based on the present invention records a driving assistance program, which is used by a computer to execute:

[0056] The step of enabling the surrounding sensors (11, 12) to acquire road markings and intersection-related information existing in the area ahead as surrounding information, wherein the area ahead is the area including the road surface in front of the vehicle (V);

[0057] If the specified execution conditions, including the detection of an intersection based on the surrounding information, are met, a step is executed to perform a driver assistance control that includes at least one of left and right turn deceleration assist control and left and right turn warning control. The left and right turn deceleration assist control automatically applies braking force to the vehicle in a manner that makes the vehicle's deceleration consistent with a target deceleration, thereby assisting the vehicle in decelerating to a specified target speed before making a right or left turn at the detected intersection. The left and right turn warning control alerts the driver of the vehicle, thereby prompting the driver to decelerate before making a right or left turn at the detected intersection.

[0058] When an intersection (I1, I2) is detected based on the surrounding information, and a road arrow mark is detected on the lane (L1, L2) in which the vehicle is traveling, the step of associating information including the road arrow mark and the travelable direction of the lane indicated by it, i.e., road arrow information, with the detected intersection and storing it in a storage device.

[0059] If, when any intersection is detected based on the surrounding information, the road surface arrow mark detected at any first time point is designated as the first road surface arrow mark, the road surface arrow information of the first road surface arrow mark is designated as the first road surface arrow information, and the road surface arrow information associated with the intersection detected at the first time point and already stored in the storage device is designated as the second road surface arrow information, then the step of determining whether the following specific condition is met is met when the number of types (t1) of directions other than the straight-ahead direction included in the travel direction of the driving lane indicated by the first road surface arrow mark is reduced compared to the number of types (t2) of directions other than the straight-ahead direction included in the travel direction of the driving lane included by the second road surface arrow information (step 840).

[0060] Based on whether the specific conditions are met, the steps of either covering the second road surface arrow information with the first road surface arrow information at the first time point and storing it, or maintaining the second road surface arrow information at the first time point, are performed; and

[0061] The step of determining whether the execution condition is met at the first time point based on the road surface arrow information after the coverage processing or the retention processing has been performed.

[0062] By having a computer execute a driving assistance program recorded on the recording medium, driving assistance controls can be performed appropriately.

[0063] In the above description, in order to help understand the invention, the constituent elements of the invention corresponding to the embodiments are added in parentheses by reference numerals used in the embodiments, but the constituent elements of the invention are not limited to the embodiments specified by the reference numerals. Attached Figure Description

[0064] Figure 1 This is a schematic configuration diagram of the driving assistance device (first implementation device) according to the first embodiment of the present invention.

[0065] Figure 2 This is a diagram illustrating the different types of arrow markings on the road surface.

[0066] Figure 3This diagram illustrates the execution conditions for deceleration assist control before left and right turns.

[0067] Figure 4 This is a diagram showing the state of the left-turn arrow on the road surface, which has become blurred due to deterioration over time.

[0068] Figure 5A It is used to set up in the driving lane. Figure 4 The diagram illustrates an example of the covering and retention processes for road arrow markings.

[0069] Figure 5B It is used to set up in the driving lane. Figure 4 The figure illustrates another example of the covering and retention process for road arrow markings.

[0070] Figure 6A This diagram illustrates an example of how to cover and retain road arrow markings when the type of road arrow markings on a driving lane changes.

[0071] Figure 6B This diagram illustrates another example of the process of covering and maintaining road arrow markings when the type of road arrow markings on a driving lane changes.

[0072] Figure 7 This is a flowchart illustrating the routine executed by the CPU of the left and right turn deceleration assist ECU of the first implementation device.

[0073] Figure 8 This is a flowchart illustrating the routines executed by the CPU.

[0074] Figure 9 This is a flowchart illustrating the routines executed by the CPU.

[0075] Figure 10A This diagram illustrates a state where stains adhere to the driving lane near the road arrow markings in a driving assistance device (second implementation device) according to the second embodiment of the present invention.

[0076] Figure 10B It is used to set up in the driving lane. Figure 10A The diagram illustrates an example of the covering and retention processes for road arrow markings.

[0077] Figure 11 This diagram illustrates an example of how to cover and retain road arrow markings when a new lane is added to the left of a driving lane.

[0078] Figure 12This is a flowchart illustrating the routine executed by the CPU of the left and right turn deceleration assist ECU of the second implementation device.

[0079] Figure 13 This is a flowchart illustrating the routine executed by the CPU of the left and right turn deceleration assist ECU of a driving assistance device (modified device) according to a variation of the present invention. Detailed Implementation

[0080] (First Implementation)

[0081] (constitute)

[0082] Hereinafter, a driving assistance device (hereinafter also referred to as "this embodiment device") according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown, this embodiment includes a left and right turn deceleration assist ECU 10 and connected to it a camera sensor 11, a radar sensor 12, a vehicle speed sensor 13, an acceleration sensor 14, an accelerator pedal operation sensor 15, a brake pedal operation sensor 16, a left and right turn deceleration assist switch 17, a turn signal switch 18, a drive unit 19, a braking unit 20, and a turn signal 21. The left and right turn deceleration assist ECU 10 has a microcomputer as its main component. ECU is an abbreviation for Electronic Control Unit. A microcomputer includes a CPU, ROM, RAM, and interfaces (I / F), etc. The CPU implements various functions by executing instructions (programs, routines) stored in the ROM. In addition, some functions can also be implemented by other ECUs. Hereinafter, the vehicle equipped with this embodiment (in other words, the vehicle equipped with this embodiment) will be referred to as the "own vehicle".

[0083] The left and right turn deceleration assist ECU 10 is configured to acquire, generate, or detect information or signals output by, or detected by the aforementioned sensors and switches 11 to 18 at predetermined intervals, and control elements 19 to 21 based on the acquired signals. Hereinafter, the left and right turn deceleration assist ECU 10 will also be referred to as "ECU 10".

[0084] Camera sensor 11 is mounted on the back of the vehicle's interior mirror (interior mirror / rearview mirror). Camera sensor 11 captures images of the landscape in front of the vehicle, including the road surface, and identifies (detects) road markings present in the area ahead based on the captured image data. Road markings include lane markings extending in front of the vehicle and road arrow markings on the driving lanes. A driving lane is the lane the vehicle is traveling in, defined as the area between two adjacent lane markings. Road arrow markings are arrow-shaped road markings indicating the permissible direction of travel for a lane; typically, multiple arrow markings are spaced apart along the direction of lane extension near intersections. Road arrow markings include "traffic division by direction of travel" and "direction of travel." "Traffic division by direction of travel" is typically placed on each lane of a road with two or more lanes on one side. On the other hand, "direction of travel" is placed where it is necessary to indicate the direction a vehicle can travel, and is therefore independent of the type of lane.

[0085] Figure 2 This is a diagram showing the main types of road arrow markings. For example... Figure 2 As shown, in road arrow mark E1, the arrow indicates a left direction, so the lane marked with arrow mark E1 is designated for left turns (i.e., this lane is a dedicated left-turn lane). In road arrow mark E2, the arrow indicates both forward and left directions, so the lane marked with arrow mark E2 is designated for both straight-ahead and left-turn directions. Hereinafter, the arrow in road arrow mark E2 indicating a left turn direction will be referred to as "left-turn arrow E2a". In road arrow mark E3, the arrow indicates forward, so the lane marked with arrow mark E3 is designated for straight-ahead directions. In road arrow mark E4, the arrow indicates both forward and right directions, so the lane marked with arrow mark E4 is designated for both straight-ahead and right-turn directions. Hereinafter, the arrow in road arrow mark E4 indicating a right turn direction will be referred to as "right-turn arrow E4a". In the road arrow marking E5, the arrow indicates the right direction, so the lane marked with this arrow E5 is for right turns (i.e., this lane is a dedicated right-turn lane).

[0086] return Figure 1Continuing the explanation, camera sensor 11 includes an image recognition ECU (not shown) that uses machine learning to identify road arrow markings. Specifically, the image recognition ECU pre-learns learning data containing all possible road arrow markings that may be marked on the road surface. The road arrow markings included in the learning data include, for example, arrow markings of different sizes and / or shapes depending on the region, and arrow markings of varying degrees of blur. Each road arrow marking is associated with and stored in the learning data with the traversable direction indicated by that arrow marking. Using the learning results from the learning data, the image recognition ECU identifies the road arrow markings from the image data and calculates their traversable direction.

[0087] In addition to road markings, the camera sensor 11 also identifies (detects) traffic lights in the area in front of its own vehicle based on image data, and calculates the relative relationship between its own vehicle and the traffic lights. Here, the "relative relationship between the vehicle and the traffic lights" includes the distance from the vehicle to the traffic lights and the position of the traffic lights relative to the vehicle. Furthermore, the camera sensor 11 can also be configured to identify moving objects such as other vehicles and pedestrians, as well as stationary objects such as the median strip and guardrails, in addition to traffic lights. The "relative relationship between the vehicle and the traffic lights" calculated by the camera sensor 11 is equivalent to an example of "information related to the intersection".

[0088] The camera sensor 11 acquires information like this as "camera surrounding information" and outputs it to the ECU 10. The camera sensor 11 is an example of an "area sensor".

[0089] The radar sensor 12 is located in the center of the front grille of the vehicle. The radar sensor 12 projects millimeter-wave radio waves towards the area in front of the vehicle and receives reflected waves from any three-dimensional objects present. Based on the timing of the radio wave projection and reception, the radar sensor 12 calculates the presence or absence of three-dimensional objects and the relative relationship between the vehicle and the objects. The radar sensor 12 obtains this information as "radar ambient information" and outputs it to the ECU 10. The radar sensor 12 is an example of an "ambient sensor."

[0090] Furthermore, the location of the radar sensor 12 is not limited to the center of the front grille; it can be located anywhere on the front end of the vehicle. For example, the radar sensor 12 can also be located in the center of the front bumper or in the center of the area between the front bumper and the front grille. Alternatively, the radar sensor 12 can be located at least one of the left or right corners of the front bumper.

[0091] The ECU 10 detects road surface arrow markings on the driving lane based on camera surrounding information and determines the permissible direction of travel for the driving lane indicated by the arrow markings. Additionally, the ECU 10 detects traffic lights based on both camera surrounding information and radar surrounding information to detect intersections. By detecting traffic lights based on both camera surrounding information and radar surrounding information, the accuracy of calculating the relative relationship between the vehicle and the traffic lights is improved. In other words, the accuracy of intersection detection is improved. Camera surrounding information and radar surrounding information are examples of "surrounding information." However, this embodiment may also lack a radar sensor 12. In this case, camera surrounding information alone is an example of "surrounding information."

[0092] The vehicle speed sensor 13 generates a signal corresponding to the vehicle's speed (hereinafter referred to as "vehicle speed"). The ECU 10 acquires the signal generated by the vehicle speed sensor 13 and calculates the vehicle speed based on the signal.

[0093] Accelerometer sensor 14 generates signals corresponding to the vehicle's acceleration and deceleration. ECU 10 receives these signals and calculates the acceleration and deceleration based on them. Deceleration has negative values. The smaller the deceleration, the greater the degree of deceleration.

[0094] The accelerator pedal operation amount sensor 15 generates a signal corresponding to the amount of operation when the driver of the vehicle depresses the accelerator pedal. The ECU 10 acquires the signal generated by the accelerator pedal operation amount sensor 15 and calculates the accelerator pedal operation amount based on the signal. If the calculated accelerator pedal operation amount is below a predetermined accelerator pedal operation amount threshold, the ECU 10 determines that no accelerator pedal operation has been performed.

[0095] The brake pedal operation amount sensor 16 generates a signal corresponding to the amount of operation when the driver depresses the brake pedal. The ECU 10 acquires the signal generated by the brake pedal operation amount sensor 16 and calculates the brake pedal operation amount based on the signal. If the calculated brake pedal operation amount is below a predetermined brake pedal operation amount threshold, the ECU 10 determines that no brake pedal operation has been performed.

[0096] The left and right turn deceleration assist switch 17 is located near the driver's seat and can be operated by the driver (hereinafter, also referred to as "deceleration assist switch 17"). The deceleration assist switch 17 is a switch that allows the driver to select whether to activate left and right turn deceleration assist control when the execution conditions described later are met. Here, left and right turn deceleration assist control is a type of driver assistance control that automatically applies braking force to the vehicle in a manner that matches the vehicle's deceleration to a target deceleration (described later), thereby assisting in decelerating the vehicle before making a right or left turn at an intersection. The target deceleration is the deceleration required to reduce the vehicle speed to a specified target speed. The target speed is the upper limit of the vehicle speed at which it can appropriately (safely) make a right or left turn at an intersection, and can be preset through experimentation or simulation. Hereinafter, left and right turn deceleration assist control will also be referred to as "deceleration assist control".

[0097] When the deceleration assist switch 17 is turned on, a control permission signal is sent to the ECU 10 during the period it is in the on state. After receiving the control permission signal, the ECU 10 executes deceleration assist control if other specified conditions are met. When the deceleration assist switch 17 is turned off, the sending of the control permission signal stops.

[0098] The turn signal switch 18 is located on the turn signal stalk WL (not shown). The turn signal stalk WL is a driver-operated device that activates (flashes) the turn signal and is located on the steering column. The turn signal stalk WL is operated by the driver when making a left or right turn or changing lanes. The turn signal stalk WL and the turn signal switch 18 are examples of a "driver" and a "direction indicator switch," respectively.

[0099] Specifically, the turn signal stalk WL is configured to move from a neutral position to a right position PR or a left position PL, centered on a pivot axis. The right position PR or left position PL represents a predetermined angle of rotation, either counterclockwise or counterclockwise. The turn signal switch 18 includes a right switch 18R and a left switch 18L. The right switch 18R is activated (generating an activation signal) when the turn signal stalk WL is in the right position PR, and deactivated (generating a deactivation signal) otherwise. The left switch 18L is activated (generating an activation signal) when the turn signal stalk WL is in the left position PL, and deactivated (generating a deactivation signal) otherwise. The ECU 10 receives the signal generated by the turn signal switch 18 and detects the operating state of the turn signal stalk WL based on this signal.

[0100] The drive unit 19 is a device for applying driving force to its drive wheels to propel the vehicle. The braking unit 20 is a device for applying braking force to its wheels to brake the vehicle.

[0101] The ECU 10 controls the driving force and / or braking force by controlling the operation of the drive unit 19 and / or the braking unit 20, thereby causing the drive unit 19 and / or the braking unit 20 to perform deceleration assist control. In this way, the deceleration assist control is performed by the ECU 10 controlling the operation of the drive unit 19 and / or the braking unit 20, so it will be referred to as "ECU 10 performing deceleration assist control" below.

[0102] The turn signal 21 includes a right turn signal 21R and a left turn signal 21L. The right turn signal 21R is located at the front right corner and the rear right corner of the vehicle. The left turn signal 21L is located at the front left corner and the rear left corner of the vehicle. The ECU 10 causes the corresponding turn signal 21 (21R, 21L) to flash while the turn signal stalk WL is in the right position PR or the left position PL (i.e., while the right switch 18R or the left switch 18L generates an on signal). Furthermore, the turn signal 21 can also be controlled by other ECUs (e.g., the instrument cluster ECU). The turn signal 21 is equivalent to an example of a "direction indicator".

[0103] (Job details)

[0104] Next, the details of the operation of ECU 10 will be explained. ECU 10 performs deceleration assist control when the execution conditions are met. The execution conditions are met when all of the following conditions 1 to 7 are met. ECU 10 terminates the deceleration assist control at the point in time when at least one of conditions 1 to 7 becomes false during the execution of the deceleration assist control.

[0105] (Condition 1) The deceleration auxiliary switch 17 is in the ON state.

[0106] (Condition 2) An intersection was detected.

[0107] (Condition 3) Road arrow information is stored in the RAM of ECU 10 (described later).

[0108] (Condition 4) The turn signal switch 18 is in the ON state.

[0109] (Condition 5) The driving direction of the driving lane included in the road arrow information includes the direction in which the turn signal switch 18 is turned on.

[0110] (Condition 6) Neither the accelerator pedal nor the brake pedal is being operated.

[0111] (Condition 7) The vehicle speed is greater than the target vehicle speed.

[0112] When the ECU 10 receives a control permission signal from the deceleration assist switch 17, it determines that condition 1 is met.

[0113] When ECU 10 detects a signal light based on information around the camera and radar, provided that condition 1 is met, it determines that condition 2 is met.

[0114] ECU 10 is configured to, when determining the permissible direction of travel of the driving lane indicated by the road surface arrow markings detected based on camera surrounding information, under conditions 1 and 2, associate and store the "information including the road surface arrow markings and the permissible direction of travel of the driving lanes indicated therein"—that is, the road surface arrow information—with the intersection (detected based on the fulfillment of condition 2) in RAM. ECU 10 is configured in principle to overwrite the road surface arrow information stored in RAM with the latest road surface arrow information. If road surface arrow information is stored in RAM under conditions 1 and 2, ECU 10 determines that condition 3 is fulfilled.

[0115] However, in a configuration that always utilizes the latest road arrow information for overlay, deceleration assist control may not be properly executed. Therefore, ECU 10 is configured not to overlay the road arrow information under specific conditions described later. Details are described later.

[0116] If conditions 1 to 3 are met, and the signal obtained from the turn signal switch 18 contains the turn-on signal of the right switch 18R or the left switch 18L, then the ECU 10 determines that condition 4 is met.

[0117] If conditions 1 to 4 are met, and the direction of the turn signal switch 18 (i.e., right direction when the right switch 18R is on, and left direction when the left switch 18L is on) falls within the permissible direction of travel of the lane included in the road arrow information, then ECU 10 determines that condition 5 is met. For example, condition 5 is met when the permissible direction of travel of the lane included in the road arrow information is "straight ahead and left turn" and the left switch 18L is on.

[0118] If conditions 1 to 5 are met, and the accelerator pedal operation amount calculated based on the signal obtained from the accelerator pedal operation amount sensor 15 is below a predetermined accelerator pedal operation amount threshold, and the brake pedal operation amount calculated based on the signal obtained from the brake pedal operation amount sensor 16 is below a predetermined brake pedal operation amount threshold, then ECU 10 determines that condition 6 is met.

[0119] If conditions 1 to 6 are met, and the vehicle speed calculated based on the signal obtained from the vehicle speed sensor 13 is greater than the target vehicle speed, then ECU 10 determines that condition 7 is met.

[0120] Reference Figure 3 Please provide a detailed explanation. Figure 3 This is a graph showing the temporal changes in the actions of a vehicle V with the intention of making a left turn at intersection I1. Figure 3 In the accompanying drawings, for ease of viewing, vehicle V is shown as a dashed line when it is positioned on the road surface arrow mark. This is also true for the other accompanying drawings described later. Furthermore, in... Figure 5B and Figure 6B In the case of mutual interference between their own vehicles V, one vehicle V is also shown as a dashed line.

[0121] exist Figure 3 In the example, suppose that the deceleration assist switch 17 is in the on state, condition 1 is met. ECU 10 detects the intersection I1 located in front of its own vehicle V by detecting the traffic light S1 at position P1. Thus, condition 2 is met. Additionally, ECU 10 detects the road arrow mark A1 of the driving lane L1 at position P1. The road arrow mark A1 is... Figure 2 The road arrow mark E2 is of the same type. Therefore, ECU 10 associates the "information including road arrow mark A1 and the permissible direction of travel (straight and left turn) of the driving lane L1 indicated by it," i.e., the road arrow information, with the intersection I1 and stores it in RAM. Thus, condition 3 is met. Hereinafter, the "permissible direction of travel of the driving lane indicated by road arrow mark X" will also be referred to as the "permissible direction of travel of road arrow mark X." In addition, the "information including road arrow mark X and the permissible direction of travel of the driving lane indicated by it" will also be referred to as the "road arrow information of road arrow mark X."

[0122] Subsequently, when vehicle V travels straight in lane L1 and reaches position P2, it becomes unable to detect road arrow mark A1, so ECU 10 detects road arrow mark A2. Road arrow mark A2 is also the same as road arrow mark E2 (refer to...). Figure 2 The same type. Therefore, the road arrow information remains essentially unchanged. Next, the driver of vehicle V operates the turn signal stalk WL to the left at position P3, moving it to the left position PL. As a result, the left switch 18L changes from the off state to the on state at position P3, so ECU 10 starts flashing the left turn signal 21L. As a result, condition 4 is met.

[0123] At location P3, the permissible directions of travel (straight and left turns) for the driving lanes included by the road surface arrow information include the direction in which turn signal switch 18 is activated (left turn). Therefore, condition 5 is met. Figure 3In the example, it is assumed that the driver did not operate the accelerator pedal or the brake pedal. Furthermore, it is assumed that at position P3, the vehicle V is traveling at a speed greater than the target speed. In this case, conditions 6 and 7 are met at position P3.

[0124] As a result, the execution conditions were met, so ECU 10 initiated deceleration assistance control at position P3. Figure 3 In the example, the execution condition is met between position P3 and position P4, so ECU 10 continues to execute the deceleration assist control. Later, when the vehicle V reaches position P4, road arrow mark A2 is no longer detected, so ECU 10 detects road arrow mark A3. Road arrow mark A3 is also related to road arrow mark E2 (refer to...). Figure 2 The same type. Therefore, the road arrow information does not change substantially, and ECU 10 continues to execute deceleration assist control. As a result, when the vehicle speed at position P5 becomes below the target speed, the execution condition becomes invalid because condition 7 is not met, so ECU 10 ends deceleration assist control.

[0125] according to Figure 3 For example, before making a left turn at intersection I1, the ECU assists in decelerating vehicle V, thus reducing its speed to the target speed so that vehicle V can make a proper (safe) left turn. Furthermore, ECU 10 is configured to, upon detecting any intersection (at... Figure 3 In the example, the road arrow information is erased from RAM at the point in time when the state (detected state) of intersection I1) changes to an undetectable state (non-detected state) (typically, the point in time when the intersection has passed).

[0126] Here, the road arrow markings are sometimes blurred due to deterioration over time. Figure 4 Show road arrow mark E2 (reference) Figure 2 The road arrow marking E2f has become blurred due to deterioration over time. Within road arrow marking E2f, only the left-turn arrow E2af is partially blurred. The left-turn arrow E2af is blurred to the point of being visually indistinguishable. Therefore, ECU 10 cannot detect the left-turn arrow E2af, and as a result, detects road arrow marking E2f as the same as road arrow marking E3 (see reference). Figure 2 The corresponding road arrow markings. Therefore, ECU 10 will determine the permissible direction of travel for the driving lane indicated by the road arrow marking E2f as the "straight direction".

[0127] Figure 5A and Figure 5B Shown in Figure 3The example shows a road arrow mark E2f replacing road arrow mark A3 on driving lane L1. (See also...) Figure 5A and Figure 5B This section explains the potential problems that may arise when the road arrow marking becomes E2f instead of A3. The following mainly addresses... Figure 3 The examples illustrate the different points.

[0128] exist Figure 5A In the example, ECU 10 initiates deceleration assist control at position P3. Subsequently, ECU 10 detects road arrow marker E2f at position P4. At this point, it is assumed that ECU 10 uses the road arrow information of road arrow marker E2f to overwrite the road arrow information of road arrow marker A2 stored in RAM. Based on this assumption, condition 5 no longer holds, so ECU 10 discontinues deceleration assist control at position P4. In this situation, the vehicle speed has not yet reached the target speed, so the driver may feel disoriented by the sudden interruption of deceleration assist control.

[0129] exist Figure 5B In the example, with Figure 5A Similarly, ECU 10 detects road arrow marker E2f at position P4. At this point, it is assumed that ECU 10 uses the road arrow information of road arrow marker E2f to overwrite the road arrow information of road arrow marker A2 stored in RAM. Based on this assumption, even if the left switch 18L changes from off to on at position P6 and the left turn signal 21L begins flashing (i.e., condition 4 is met), condition 5 is not met, so ECU 10 will not initiate deceleration assist control at position P6. If the vehicle speed has not yet reached the target speed, the driver may be confused as to why the deceleration assist control is not working.

[0130] exist Figure 5A and Figure 5B The text describes the situation where vehicle V makes a left turn, but the same problem may occur when making a right turn. For example, when the left or right turn arrows on the road become blurred due to time-related degradation to the point that camera sensor 11 cannot recognize them, the deceleration assist control may be interrupted or fail to function, thus preventing proper execution of the control.

[0131] In addition, the same problem can occur even if road arrow markings do not become blurred over time. See below for reference. Figure 6A and Figure 6B To explain. Figure 6A and Figure 6BThis is a diagram showing the temporal changes in the actions of a vehicle V intending to make a left turn at intersection I2. A pedestrian overpass (not shown) is located at intersection I2. Figure 6A and Figure 6B As shown, road arrow markings B1 and B2 are provided on driving lane L2. There is no dedicated left-turn lane on this road. Therefore, before intersection I2, driving lane L2 branches into a lane allowing straight travel and a lane allowing left turns. Consequently, the permissible direction of travel for road arrow marking B1 becomes "straight and left-turn," while the permissible direction of travel for road arrow marking B2 becomes "straight only," and the left-turn arrow disappears. That is, in driving lane L2, the type of road arrow marking changes due to the layout of intersection I2.

[0132] exist Figure 6A and Figure 6B In any example, it is assumed that the deceleration assist switch 17 is in the ON state, and condition 1 is met. Alternatively, it is assumed that ECU 10 is at position P7 (refer to...) before the vehicle reaches its own position V. Figure 6A The time point is earlier than the time point (illustration omitted), the intersection I2 is detected, and the road arrow mark B1 is detected and the road arrow information is stored in RAM (that is, conditions 2 and 3 are met).

[0133] exist Figure 6A In the example, at position P7, the left switch 18L changes from the off state to the on state (the left turn signal 21L begins to flash). Thus, condition 4 is met. Subsequently, when the vehicle V travels straight in lane L2 and reaches position P8, road arrow marker B1 is no longer detected, so ECU 10 detects road arrow marker B2. At this point, it is assumed that ECU 10 uses the road arrow information of road arrow marker B2 to overwrite the road arrow information of road arrow marker B1 stored in RAM. Based on this assumption, condition 5 is no longer met, so ECU 10 interrupts deceleration assist control at position P8. In this situation, the vehicle speed has not yet reached the target speed, so the driver may feel disoriented by the sudden interruption of deceleration assist control.

[0134] exist Figure 6B In the example, with Figure 6ASimilarly, ECU 10 detects road arrow marker B2 at position P8. At this point, it is assumed that ECU 10 uses the road arrow information of road arrow marker B2 to overwrite the road arrow information of road arrow marker B1 stored in RAM. Based on this assumption, even if the left switch 18L changes from off to on at position P9 and the left turn signal 21L begins flashing (i.e., condition 4 is met), condition 5 is not met, so ECU 10 will not initiate deceleration assist control at position P9. If the vehicle speed has not yet reached the target speed, the driver may be confused as to why the deceleration assist control is not working.

[0135] exist Figure 6A and Figure 6B The example describes the situation where vehicle V makes a left turn, but the same problem may occur when making a right turn. For instance, when the type of road arrow markings changes due to the intersection layout (typically, the left-turn arrow disappears on the left lane and the right-turn arrow disappears on the right lane), the deceleration assist control may be interrupted or fail to function, thus preventing proper execution of the control.

[0136] Therefore, in this embodiment, when conditions 1 to 3 are met, the ECU 10 determines whether the following specific condition is met. This specific condition is met when the number of directions other than the straight-ahead direction included in the travel direction of the driving lane indicated by the road arrow mark (hereinafter referred to as "first road arrow mark") detected at any first time point is reduced compared to the number of directions other than the straight-ahead direction included in the travel direction of the driving lane included in the road arrow information (hereinafter referred to as "second road arrow information") associated with the intersection (the intersection detected based on the fulfillment of condition 2) stored in RAM at the first time point. Here, the second road arrow information stored in RAM at the first time point is the road arrow information covered by a second time point earlier than the first time point. That is, the road arrow mark included in the second road arrow information is the road arrow mark detected at the second time point. Hereinafter, this road arrow mark is referred to as "second road arrow mark".

[0137] Under certain conditions, the second road surface arrow information is not overwritten (i.e., the process of maintaining the second road surface arrow information is performed). On the other hand, if the specific conditions are not met, the overwriting process is performed to overwrite the second road surface arrow information using the first road surface arrow information (the road surface arrow information marked by the first road surface arrow) and store it in RAM.

[0138] Here, regarding "the type t1 of directions other than the straight-ahead direction included in the travel direction of the driving lane indicated by the first road surface arrow mark", for example, the first road surface arrow marks are arrow marks E1 to E5 (see reference). Figure 2 In the case of ), it refers to the left turn direction, left turn direction, none, right turn direction, and right turn direction in that order. Similarly, regarding "the type t2 of the travel directions of the driving lanes included in the second road surface arrow information, other than the straight-ahead direction", for example, when the second road surface arrow markings are arrow markings E1 to E5 (refer to...), Figure 2 In the case of ), the directions are left turn, left turn, none, right turn, and right turn, respectively.

[0139] For example, the first road surface arrow is marked as arrow mark E2f (see reference). Figure 4 ) or arrow mark E3 (see reference) Figure 2 The second road surface arrow is marked as arrow mark E2 (refer to...). Figure 2 In the case of "none" for category t1 and "left turn direction" for category t2, the number of categories t1 is reduced compared to category t2. In this case, ECU 10 determines that the specific condition is met and does not overwrite the second road arrow information.

[0140] Additionally, for example, the first road surface arrow is marked as arrow mark E2 (see reference). Figure 2 When the second road surface arrow is marked as arrow mark E2, both type t1 and t2 are "left turn direction", so type t1 and type t2 are the same. In this case, ECU 10 determines that the specific condition is not met and uses the first road surface arrow information to cover the second road surface arrow information.

[0141] Furthermore, for example, the first road surface arrow is marked as arrow mark E2 (refer to...). Figure 2 The second road surface arrow is marked as arrow mark E2f (refer to...). Figure 4 In the case of "left turn direction", category t1 is "left turn direction" and category t2 is "none", so category t1 increases compared to category t2. In this case, ECU 10 determines that the specific condition is not met and uses the first road surface arrow information to cover the second road surface arrow information.

[0142] Furthermore, regarding the addition or removal of "types of directions other than straight-ahead directions included in the permissible travel directions," separate judgments are made for right-turn and left-turn directions. That is, for example, consider the case where ECU 10 misidentifies a road arrow marking, causing the first road arrow marking to be arrow marking E2 (refer to...). Figure 2 The second road surface arrow is marked as arrow mark E4 (refer to...). Figure 2In this case, category t1 is "left turn direction" and category t2 is "right turn direction". Therefore, regarding the left turn direction, category t1 increases compared to category t2, and regarding the right turn direction, category t1 decreases compared to category t2.

[0143] Based on this structure, Figure 5A In the example, conditions 1 to 3 are met at position P4 (strictly speaking, condition 4 is also met), so ECU 10 determines whether a specific condition is met. At position P4, the first road arrow marker is arrow marker E2f, and the second road arrow marker is arrow marker A2. In this case, category t1 ("none") is reduced compared to category t2 ("left turn direction"). Therefore, ECU 10 determines that the specific condition is met and does not overwrite the road arrow information of road arrow marker A2 stored in RAM. Thus, condition 5 is met at position P4. At this time, if conditions 6 and 7 are assumed to be met, then the condition is met at position P4, so it is possible to suppress the interruption of deceleration assist control at position P4, and can greatly reduce the possibility of the driver feeling uneasy due to the sudden interruption of this control.

[0144] exist Figure 5B In the example, conditions 1 through 3 are met at position P4, so ECU 10 determines whether a specific condition is met. At position P4, the first road arrow marker is arrow marker E2f, and the second road arrow marker is arrow marker A2. In this case, category t1 ("none") is reduced compared to category t2 ("left turn direction"). Therefore, ECU 10 determines that the specific condition is met and does not overwrite the road arrow information of road arrow marker A2 stored in RAM. Thus, when condition 4 is met at position P6, condition 5 is also met simultaneously. At this time, if conditions 6 and 7 are assumed to be met, deceleration assist control starts at position P6, thus significantly reducing the possibility of the driver being confused due to the inoperability of this control.

[0145] exist Figure 6AIn the example, conditions 1 through 3 are met at position P8 (strictly speaking, condition 4 is also met), so ECU 10 determines whether a specific condition is met. At position P8, the first road arrow marker is arrow marker B2, and the second road arrow marker is arrow marker B1. In this case, category t1 ("none") is reduced compared to category t2 ("left turn direction"). Therefore, ECU 10 determines that the specific condition is met and does not overwrite the road arrow information of road arrow marker B1 stored in RAM. Thus, condition 5 is met at position P8. At this time, if conditions 6 and 7 are assumed to be met, then the condition is met at position P8, so it is possible to suppress the interruption of deceleration assist control at position P8, and can significantly reduce the possibility of the driver feeling uneasy due to the sudden interruption of this control.

[0146] exist Figure 6B In the example, conditions 1 through 3 are met at position P8, so ECU 10 determines whether a specific condition is met. At position P8, the first road arrow marker is arrow marker B2, and the second road arrow marker is arrow marker B1. In this case, category t1 ("none") is reduced compared to category t2 ("left turn direction"). Therefore, ECU 10 determines that the specific condition is met and does not overwrite the road arrow information of road arrow marker B1 stored in RAM. Thus, when condition 4 is met at position P9, condition 5 is also met simultaneously. At this time, if conditions 6 and 7 are assumed to be met, deceleration assist control starts at position P9, thus significantly reducing the possibility of the driver being confused due to the inoperability of this control.

[0147] In this embodiment, the road arrow information stored in RAM is not overwritten under certain conditions (i.e., the road arrow information is retained). Thus, even if the left-turn or right-turn arrows on the road markings become blurred due to time-related degradation to the point that the camera sensor 11 cannot recognize them, or if the type of road arrow markings changes due to the layout of the intersection, the interruption or failure of the deceleration assist control can be suppressed, and the control can be executed appropriately.

[0148] (Specific tasks)

[0149] Next, the specific operation of ECU 10 will be explained. The CPU of ECU 10 is configured to repeatedly execute in parallel after a predetermined calculation period while the ignition switch is in the ON position. Figure 7 and Figure 8 The flowchart shows the routines and... Figure 9 The routine is shown in the flowchart.

[0150] When the specified timing is reached, the CPU... Figure 7 The process begins at step 700 and proceeds to step 705, where, based on whether a control permission signal is received from the deceleration assist switch 17, it is determined whether the deceleration assist switch 17 is in the ON state (condition 1). If the switch 17 is in the OFF state (step 705: No), the CPU proceeds to step 755.

[0151] In step 755, the CPU determines whether the value of the control execution flag is 1. The control execution flag indicates whether deceleration assist control is being executed. A value of 1 indicates that deceleration assist control is being executed, while a value of 0 indicates that deceleration assist control is not being executed. If deceleration assist control has not yet started and the value of the control execution flag is 0 (step 755: No), the CPU proceeds to step 795 and temporarily terminates the current routine.

[0152] On the other hand, when the deceleration assist switch 17 is in the ON state (step 705: Yes), the CPU proceeds to step 710 and determines whether an intersection (in this embodiment, a traffic light) has been detected based on the camera's surrounding information and the radar's surrounding information (condition 2). If no intersection is detected (step 710: No), the CPU proceeds to step 755 and performs the above-described processing, and then proceeds to step 795 to temporarily end this routine.

[0153] On the other hand, if an intersection is detected (step 710: Yes), the CPU proceeds to step 715 to perform road arrow information overlay / maintenance processing. See reference... Figure 8 This process will be explained. After the CPU proceeds to step 715, from... Figure 8 The process begins at step 800 and proceeds to step 810, where it determines whether a road arrow mark has been detected based on information about the camera's surroundings. If no road arrow mark is detected (step 810: No), the CPU proceeds to step 895 and temporarily terminates the current routine.

[0154] On the other hand, if a road arrow mark is detected (step 810: Yes), the CPU proceeds to step 820, and determines the result in step 710 (refer to...). Figure 7 The CPU checks whether the road surface arrow information associated with the intersection detected in step 810 has been stored in RAM. If the road surface arrow information has not yet been stored in RAM (step 820: No), the CPU proceeds to step 830, associates the road surface arrow information marked by the road surface arrow detected in step 810 with the intersection detected in step 710, and stores it in RAM. Then, the CPU proceeds to step 895 and temporarily terminates this routine.

[0155] On the other hand, when the road surface arrow information associated with the intersection has been stored in the RAM (step 820: Yes), the CPU proceeds to step 840 to determine whether a specific condition is satisfied. This is done by determining whether the relationship of t1 < t2 holds between the types t1 of directions other than the straight-ahead direction included in the feasible travel direction of the road surface arrow mark detected in step 810 and the types t2 of directions other than the straight-ahead direction included in the feasible travel direction of the travel lane included in the road surface arrow information stored in the RAM.

[0156] When the specific condition is satisfied (t1 < t2) (step 840: Yes), the CPU proceeds to step 850 to perform a holding process for holding the road surface arrow information stored in the RAM (that is, the road surface arrow information is not overwritten). On the other hand, when the specific condition is not satisfied (t1 ≥ t2) (step 840: No), the CPU proceeds to step 860 to perform an overwrite process of overwriting the road surface arrow information with the road surface arrow information of the road surface arrow mark detected in step 810 and storing it in the RAM. After the process of step 850 or step 860 is completed, the CPU proceeds to Figure 7 step 720.

[0157] In step 720, the CPU determines whether the road surface arrow information is stored in the RAM (condition 3) based on the result of the road surface arrow information overwrite / holding process (refer to Figure 8 ). When the road surface arrow information is not stored (step 720: No), the CPU proceeds to step 755 to perform the above-described process, and then proceeds to step 795 to temporarily end this routine. In addition, the case where the road surface arrow information is not stored means the case where "No" is determined in step 810 (refer to Figure 8 ).

[0158] On the other hand, when the road surface arrow information is stored (step 720: Yes), the CPU proceeds to step 725 to determine whether the turn signal switch 18 (right switch 18R or left switch 18L) is in the ON state (condition 4) based on the signal obtained from the turn signal switch 18. When the turn signal switch 18 is in the OFF state (step 725: No), the CPU proceeds to step 755 to perform the above-described process, and then proceeds to step 795 to temporarily end this routine.

[0159] On the other hand, when the turn signal switch 18 is in the on state (step 725: Yes), the CPU proceeds to step 730 and determines whether the "on direction of the turn signal switch 18" is included in the "travelable direction of the driving lane included in the road arrow information stored in RAM (travelable direction marked by the road arrow)" (condition 5). If the on direction is not included in the travelable direction (step 730: No), the CPU proceeds to step 755 and performs the above-mentioned processing, and then proceeds to step 795 and temporarily ends this routine.

[0160] On the other hand, if the traversable direction includes an engaging direction (step 730: Yes), the CPU proceeds to step 735 and, based on the signals obtained from the accelerator pedal operation amount sensor 15 and the brake pedal operation amount sensor 16 respectively, determines whether the driver has operated the accelerator pedal or the brake pedal (condition 6). If either pedal operation has been performed (step 735: Yes), the CPU proceeds to step 755 to perform the above-described processing, and then proceeds to step 795 to temporarily terminate this routine.

[0161] On the other hand, if no pedal operation is performed (step 735: no), the CPU proceeds to step 740 to determine whether the vehicle speed is greater than the preset target vehicle speed (condition 7).

[0162] If the vehicle speed is below the target speed (step 740: No), and the value of the control execution flag is 0 in step 755 (i.e., deceleration assist control is not being executed) (step 755: No), the CPU determines that the vehicle can make a proper left or right turn at the intersection based on the current vehicle speed, and proceeds to step 795 and temporarily ends the current routine (i.e., deceleration assist control is not executed).

[0163] On the other hand, if the vehicle speed is greater than the target speed (step 740: Yes), the CPU determines that, based on the current speed, the vehicle may not be able to make appropriate left or right turns at the intersection (in other words, since conditions 1 to 7 are all met, the execution conditions are met), and proceeds to step 745. In step 745, the CPU calculates the deceleration required to make the vehicle speed match the target speed as the "target deceleration for deceleration assist control," and then proceeds to step 750 to begin (execute) deceleration assist control. Additionally, the value of the control execution flag is set to 1. Afterwards, the CPU proceeds to step 795 and temporarily terminates this routine.

[0164] In contrast, when the vehicle speed is below the target vehicle speed (step 740: No), and when the value of the control execution flag is controlled to be 1 in step 755 (i.e., deceleration assistance control is being executed) (step 755: Yes), the CPU determines that the vehicle speed has been successfully decelerated to the target vehicle speed through the execution of the deceleration assistance control, proceeds to step 760, and ends the deceleration assistance control. In addition, the value of the control execution flag is set to 0. After that, the CPU proceeds to step 795 and temporarily ends this routine.

[0165] In addition, after the deceleration assistance control starts (control execution flag = 1), when it is determined as "No" in any one of steps 705, 710, 720, 725, and 730, and when it is determined as "Yes" in step 735, the CPU determines that the execution condition has become not satisfied and proceeds to step 755. Since the value of the control execution flag is set to 1, the CPU determines as "Yes" in step 755, proceeds to step 760, and interrupts the deceleration assistance control. In addition, the value of the control execution flag is set to 0. After that, the CPU proceeds to step 795 and temporarily ends this routine.

[0166] In parallel with this, the CPU starts processing from step 900 of Figure 9 and proceeds to step 910, and determines whether the state changes from the state where an intersection is detected (detection state) to the state where it is not detected (non-detection state) based on the camera surrounding information and the radar surrounding information. When the state changes from the detection state to the non-detection state (step 910: Yes), the CPU determines that the intersection has been passed, proceeds to step 920, and erases the road surface arrow information stored in the RAM. After that, the CPU proceeds to step 995 and temporarily ends this routine.

[0167] On the other hand, when the detection state is maintained and when an intersection is not detected from the beginning (step 910: No), the CPU proceeds to step 995 and temporarily ends this routine.

[0168] As described above, according to the present implementation device, when the specific condition is not satisfied (i.e., when t1 = t2 or t1 > t2), the covering process is performed, and when the specific condition is satisfied (i.e., when t1 < t2), the holding process is performed. When the specific condition is not satisfied, the first road surface arrow information is equally accurate as the second road surface arrow information or is more likely to be more accurate than the second road surface arrow information. On the other hand, when the specific condition is satisfied, the first road surface arrow information is likely to have less information content (less accurate than the second road surface arrow information) compared to the second road surface arrow information. Therefore, according to the configuration of the present implementation device, it is possible to determine whether the execution condition is satisfied based on the more accurate road surface arrow information including the travelable direction, so that the deceleration assistance control before left and right turns can be appropriately executed.

[0169] (Second Implementation)

[0170] Next, the driving assistance device (hereinafter also referred to as the "second implementation device") according to the second embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, for configurations and processes identical to those of the first implementation device, the same reference numerals and step numbers will be used, and detailed descriptions will be omitted. This also applies to the variations described later.

[0171] The second implementing device differs from the first implementing device in that it is configured to perform overriding processing even when deceleration assist control is not being executed, provided that certain conditions are met. Referring hereafter... Figures 10A to 12 This section provides specific explanations of the differences.

[0172] Figure 10A The arrow mark E3 on the road surface is shown (see reference). Figure 2 The vehicle lane near the vehicle has a stain D. Stain D is located near the road arrow mark E2 (see reference). Figure 2 The ECU 10 mistakenly detects the stain D as the left-turn arrow E2a. Consequently, it detects the road arrow mark E3 as the same as the road arrow mark E2. Hereinafter, this road arrow mark will be referred to as "road arrow mark E3d". Due to the above misdetection, the ECU 10 determines the permissible direction of travel for the lane indicated by the road arrow mark E3d as "straight ahead and left turn".

[0173] Figure 10B This is a diagram showing the time-varying actions of vehicle V with the intention of changing lanes. An intersection (not shown) is located in front of vehicle V. Figure 10B In the example, it is assumed that the deceleration assist switch 17 is in the on state, and condition 1 is met. In addition, it is assumed that the ECU 10 detects the intersection at a time point (not shown in the figure) before its own vehicle V arrives at position P10, and detects the road arrow mark C1 and stores the road arrow information in RAM (that is, conditions 2 and 3 are met).

[0174] exist Figure 10BIn the example, when the host vehicle V travels straight on the driving lane L3 and reaches the position P11, the road surface arrow mark C1 becomes undetectable, so the ECU 10 detects the road surface arrow mark C2. In this example, since the specific condition is not satisfied, the ECU 10 uses the road surface arrow information of the road surface arrow mark C2 to overwrite the road surface arrow information of the road surface arrow mark C1 stored in the RAM at the position P11. Thereafter, the driver rotates the turn signal lever WL counterclockwise at the position P12 for the purpose of changing lanes. As a result, the left switch 18L changes from the off state to the on state, and the flashing of the left turn signal 21L starts (i.e., the condition 4 is satisfied). The travelable direction of the road surface arrow mark C2 is the "straight-ahead direction", and the condition 5 is not satisfied, so the ECU10 does not start the deceleration assist control. When changing lanes, deceleration assist control is not required. Therefore, according to this configuration, the driver is not hindered by the deceleration assist control and can appropriately perform the lane change.

[0175] In contrast, consider the case where Figure 10B is provided with Figure 10A the road surface arrow mark E3d instead of the road surface arrow mark C1. In this case, at the position P10, the road surface arrow information of the road surface arrow mark E3d is stored in the RAM. Thereafter, when the host vehicle V reaches the position P11, the ECU 10 detects the road surface arrow mark C2. In this example, the specific condition is satisfied (t1 < t2). It is assumed that at this time point, the ECU 10 performs the holding process (i.e., the road surface arrow information of the road surface arrow mark E3d is held). According to this assumption, the condition 5 is satisfied at the time point when the left switch 18L changes to the on state at the position P12. At this time, if it is assumed that the conditions 6 and 7 are satisfied, the condition is satisfied at the position P12, so the deceleration assist control will start against the driver's intention, resulting in unnecessary work.

[0176] Therefore, in the present embodiment, it is configured such that even when the specific condition is satisfied and the deceleration assist control is not being executed, the overwrite process is performed. In Figure 10B the example, at the time point when the specific condition is satisfied at the position P11, the condition 4 is not yet satisfied, so the deceleration assist control is not being executed. Therefore, at the position P11, the road surface arrow information of the road surface arrow mark E3d is overwritten by the road surface arrow information of the road surface arrow mark C2. Therefore, even when the left switch 18L changes to the on state at the position P12, the condition 5 is no longer satisfied, and thus the generation of unnecessary work of the deceleration assist control can be suppressed.

[0177] Figure 11 is a diagram showing the time-lapse change of the behavior of the host vehicle V having the intention of changing lanes when a lane L6 is additionally provided to the left of the driving lane L5. An intersection not shown is located in front of the host vehicle V. In Figure 11In the example, it is assumed that the deceleration assist switch 17 is in the ON state and Condition 1 is satisfied. Additionally, it is assumed that the ECU 10 detects an intersection at a time point (not shown in the figure) before the host vehicle V reaches position P13, and detects the road surface arrow mark D1 and stores its road surface arrow information in the RAM (i.e., Condition 2 and Condition 3 are satisfied).

[0178] In Figure 11 the example, when the host vehicle V travels straight on the driving lane L5 and reaches position P14, the road surface arrow mark D1 becomes undetectable, so the ECU 10 detects the road surface arrow mark D2. In this example, specific conditions are satisfied at position P14 (t1 < t2), but at this position P14, the driver has not yet operated the turn signal lever WL, so Condition 4 is not satisfied, and thus the deceleration assist control is not being executed. Therefore, at position P14, the road surface arrow information of the road surface arrow mark D1 is overwritten by the road surface arrow information of the road surface arrow mark D2. Accordingly, even if the left switch 18L changes to the ON state at position P15, Condition 5 is no longer satisfied, thereby suppressing the occurrence of redundant operation of the deceleration assist control.

[0179] Next, regarding the specific operation of the ECU 10, the differences from the first embodiment will be mainly described. The CPU of the ECU 10 is configured to, during the period when the ignition switch is in the ON position, repeatedly execute Figure 8 instead of Figure 12 the routine shown in the flowchart in

[0180] Figure 12 The routine of Figure 8 differs from the routine of Figure 12 in the following aspect: In the routine of

[0181] a step 1210 is added between step 840 and step 850. Specifically, when specific conditions are satisfied (step 840: YES), the CPU proceeds to step 1210 and determines whether the value of the control execution flag is 1. When the value of the control execution flag is 0 (step 1210: NO), the CPU determines that the deceleration assist control is not being executed and proceeds to step 860 to overwrite the road surface arrow information. That is, in the present embodiment, even when specific conditions are satisfied, the overwrite process is performed when the deceleration assist control is not being executed. Thereby, the occurrence of redundant operation of the deceleration assist control when the driver operates the turn signal lever WL for the purpose of lane change is suppressed.

[0181] On the other hand, when the control execution flag is set to 1 (step 1210: Yes), the CPU determines that deceleration assist control is in effect and proceeds to step 850 while maintaining the road arrow information (without overwriting it). When deceleration assist control is in effect, it is assumed that the vehicle intends to make a left or right turn at the intersection. Therefore, by maintaining the information in such a situation, the possibility of sudden interruption of deceleration assist control can be reduced.

[0182] (Modified Example)

[0183] Next, a driving assistance device (hereinafter also referred to as "modified device") according to a modified example of the present invention will be described with reference to the accompanying drawings.

[0184] The deformation device differs from the first implementation device in that it is configured to calculate the reliability of road surface arrow markings detected based on information surrounding the camera, and determine whether a specific condition is met only if the reliability is above a predetermined reliability threshold. Hereinafter, refer to... Figure 13 This section provides specific explanations of the differences.

[0185] The CPU of ECU 10 is configured to, during the period when the ignition switch is in the ON position, replace [the CPU] after a predetermined calculation time. Figure 8 And repeated execution Figure 13 The routine is shown in the flowchart.

[0186] Figure 13 routines and Figure 8 Compared to the routines, the difference lies in the following point: Figure 13 In the routine, step 1310 is added between steps 810 and 820. Specifically, when the CPU detects a road arrow mark based on information around the camera (step 810: Yes), it proceeds to step 1310 to calculate the reliability of the road arrow mark. Multiple types of road arrow mark samples are pre-stored in the ROM of the ECU 10 as road arrow mark groups. The ECU 10 selects the road arrow mark most similar to the road arrow mark detected in step 810 from the road arrow mark groups stored in the ROM, and calculates the "similarity of the detected road arrow mark relative to the selected road arrow mark" using a well-known pattern matching method. The level of this similarity reflects the reliability of the detected road arrow mark; therefore, similarity will also be referred to as "reliability" below.

[0187] If the reliability is above the specified reliability threshold (step 1310: Yes), the CPU executes steps 820 to 860, proceeds to step 1395, and then moves on to the next step. Figure 7Step 720. On the other hand, if the reliability is less than the reliability threshold (step 1310: No), the CPU proceeds to step 850 for holding processing. Furthermore, the reliability threshold is set to a value that enables the ECU 10 to determine the drivable direction of the road arrow marking with a specified accuracy.

[0188] According to this configuration, the accuracy of the road surface arrow information is guaranteed, thus improving the precision of determining whether a specific condition is met, and consequently, improving the precision of determining whether the execution condition is met. Therefore, deceleration assist control can be executed more appropriately. Furthermore, the configuration of the deformation device can also be applied to the second implementation device.

[0189] The driving assistance device, vehicle, driving assistance method and recording medium involved in the above embodiments and modifications have been described. However, the present invention is not limited to the above embodiments and various modifications can be made without departing from the purpose of the present invention.

[0190] For example, in the above embodiments and variations, the execution condition is established when all conditions 1 to 7 are met, but the conditions for establishing the execution condition are not limited to this. For example, the driving assistance device may not have a deceleration assist switch 17. In this case, the execution condition may not include condition 1.

[0191] Alternatively, ECU 10 can be configured to determine whether the driver has performed a right turn or left turn based on a steering angle sensor and / or steering torque sensor (not shown). If the "direction in which the steering operation was performed" is included in the "travelable direction of the driving lane contained in the road arrow information", then conditions 4 and 5 are deemed to be met.

[0192] Furthermore, condition 6 could also be "accelerator pedal operation is not in progress." That is, it could also mean that even if the driver is operating the brake pedal, deceleration assist control is executed if the vehicle speed has not reached the target speed (provided other conditions are met). Alternatively, condition 6 could also be "brake pedal operation is not in progress." That is, it could also mean that even if the driver is operating the accelerator pedal, deceleration assist control is executed if the vehicle speed has not reached the target speed (provided other conditions are met).

[0193] Furthermore, condition 6 could also be "the driver is not performing acceleration or deceleration operations." This condition could, for example, apply to driver assistance devices installed in one-pedal vehicles. Here, a one-pedal vehicle refers to a vehicle capable of acceleration and deceleration with a single pedal; typically, it is a vehicle that accelerates when the pedal is pressed and decelerates when the pedal is released.

[0194] Furthermore, it can also be configured as a substitute or supplement to the left and right turn pre-turn deceleration assist control, executing left and right turn pre-turn warning control when the execution conditions are met. Left and right turn pre-turn warning control is a control that prompts the driver to decelerate their vehicle before making a right or left turn at an intersection by issuing an alarm. The alarm can be issued either through a speaker (voice) or through a buzzer (vibration).

[0195] Furthermore, pedestrian crossings (a type of road marking) are typically provided near intersections. Near intersections, pedestrian crossings include a first pedestrian crossing positioned across a road including the driving lane, and a second pedestrian crossing positioned across an intersecting road. The camera sensor 11 can also be configured to identify at least one of the first and second pedestrian crossings, either as an alternative to or as a supplement to traffic light recognition based on image data, and calculate the relative relationship between the vehicle and the pedestrian crossing. The ECU 10 can also detect intersections based on this relative relationship. In this case, the "relative relationship between the vehicle and the pedestrian crossing" is equivalent to an example of "information related to the intersection." Additionally, although there are cases where pedestrian crossings are provided on roads other than near intersections, road arrow markings are usually not placed in front of such pedestrian crossings, so deceleration assist control before left and right turns is not performed.

[0196] Furthermore, there are cases where a central median strip is located near an intersection. This central median strip extends along the direction of the driving lanes on the road, including the driving lanes, and temporarily discontinues within the intersection. Therefore, the camera sensor 11 can also be configured to identify the central median strip, either as a substitute for or as a supplement to traffic light recognition based on image data, and calculate the relative relationship between its own vehicle and the central median strip. The ECU 10 can also detect the location where the central median strip is discontinuous, based on this relative relationship, as an intersection. In this case, the "relative relationship between the vehicle and the central median strip" is equivalent to an example of "information related to the intersection." Additionally, the ECU 10 can also detect the central median strip based on information surrounding the camera and radar.

[0197] Furthermore, the first implementing device, the second implementing device, and the transforming device can also be mounted on vehicles used in countries where right-hand traffic is permitted. Additionally, the present invention is also applicable to vehicles that operate under automatic driving control (so-called autonomous vehicles).

[0198] Explanation of reference numerals in the attached figures

[0199] 10: Left and right turn deceleration assist ECU; 11: Camera sensor; 12: Radar sensor; 13: Vehicle speed sensor; 14: Acceleration sensor; 15: Accelerator pedal operation sensor; 16: Brake pedal operation sensor; 17: Left and right turn deceleration assist switch; 18: Turn signal switch; 19: Drive unit; 20: Braking unit; 21: Turn signal

Claims

1. A driving assistance device, comprising: Ambient sensors acquire road markings and intersection-related information present in the area ahead as ambient information, wherein the area ahead includes the road surface in front of the vehicle; and The control unit, having a storage device, is configured to, when predetermined execution conditions are met, including the detection of an intersection based on the surrounding information, execute driver assistance controls including at least one of left / right turn pre-turn deceleration assist control and left / right turn pre-turn warning control. The left / right turn pre-turn deceleration assist control automatically applies braking force to the vehicle in a manner that matches the vehicle's deceleration to a target deceleration, thereby assisting the vehicle in decelerating to a predetermined target speed before making a right or left turn at the detected intersection. The left / right turn pre-turn warning control alerts the driver of the vehicle, thereby prompting the driver to decelerate before making a right or left turn at the detected intersection. The control unit is configured as follows: When a road surface arrow mark is detected in the lane in which the vehicle is traveling (i.e., the driving lane) based on the surrounding information, the system can associate and store information including the road surface arrow mark and the permissible direction of travel indicated by it (i.e., the driving lane) with the detected intersection in the storage device. If, based on the surrounding information, any intersection is detected, and the road surface arrow marker detected at any first time point is designated as a first road surface arrow marker, the road surface arrow information of the first road surface arrow marker is designated as first road surface arrow information, and the road surface arrow information associated with the intersection detected at the first time point and already stored in the storage device is designated as second road surface arrow information, then it is determined whether the following specific condition is met: the specific condition is met if the number of directions other than the straight-ahead direction included in the travel direction of the lane indicated by the first road surface arrow marker is reduced compared to the number of directions other than the straight-ahead direction included in the travel direction of the lane indicated by the second road surface arrow information. If the specific conditions are not met, a coverage process is performed whereby the first road surface arrow information is used to cover the second road surface arrow information and the information is stored at the first time point. Under the specific conditions, Perform the process of maintaining the second road surface arrow information at the first time point, or The hold process is performed when the control execution condition, which is established while the driving assistance control is being executed, is met; the overwrite process is performed when the control execution condition is not met. Based on the road surface arrow information after the coverage processing or the retention processing, determine whether the execution condition is met at the first time point.

2. The driving assistance device according to claim 1, wherein, The control unit is configured to, Multiple types of road arrow mark samples are pre-stored in a non-volatile storage device as a road arrow mark group. If a road arrow mark is detected based on the surrounding information, the road arrow mark most similar to the detected road arrow mark is selected from the group of road arrow marks. The similarity between the detected road arrow markings and the selected road arrow markings is calculated as the reliability of the detected road arrow markings. The retention process is performed when the reliability is less than a specified reliability threshold.

3. The driving assistance device according to claim 1 or 2, wherein, It also includes a turn indicator switch, which can detect the operating status of a control operated by the driver of the vehicle to activate the turn indicator. The control unit is configured to, When an intersection is detected based on the surrounding information, and the operating state of the operator detected by the direction indicator switch corresponds to the travelable direction of the driving lane indicated by the road surface arrow information stored in the storage device, the execution condition is determined to be met.

4. A vehicle having a driving assistance device as described in any one of claims 1 to 3.

5. A driving assistance method, comprising the following steps: The surrounding sensors acquire road markings and intersection-related information existing in the area ahead as surrounding information, wherein the area ahead includes the road surface in front of the vehicle. If the specified execution conditions, including the detection of an intersection based on the surrounding information, are met, a driver assistance control is executed, including at least one of left and right turn deceleration assist control and left and right turn warning control. The left and right turn deceleration assist control automatically applies braking force to the vehicle in a manner that makes the vehicle's deceleration consistent with the target deceleration, thereby assisting the vehicle in decelerating to a specified target speed before making a right or left turn at the detected intersection. The left and right turn warning control alerts the driver of the vehicle, thereby prompting the driver to decelerate before making a right or left turn at the detected intersection. When a road arrow mark is detected on the lane in which the vehicle is traveling, i.e. the driving lane, when an intersection is detected based on the surrounding information, the road arrow information, including the road arrow mark and the driving direction indicated by it, is associated with the detected intersection and stored in the storage device. If, based on the surrounding information, any intersection is detected, and the road surface arrow mark detected at any first time point is designated as the first road surface arrow mark, the road surface arrow information of the first road surface arrow mark is designated as the first road surface arrow information, and the road surface arrow information associated with the intersection detected at the first time point and already stored in the storage device is designated as the second road surface arrow information, then it is determined whether the following specific condition is met: the specific condition is met when the number of directions other than the straight-ahead direction included in the travel direction of the driving lane indicated by the first road surface arrow mark is reduced compared to the number of directions other than the straight-ahead direction included in the travel direction of the driving lane included by the second road surface arrow information; If the specific conditions are not met, a coverage process is performed whereby the first road surface arrow information is used to cover the second road surface arrow information and the information is stored at the first time point. Under the specific conditions, Perform the process of maintaining the second road surface arrow information at the first time point, or When the control execution condition that is established while the driving assistance control is being executed is met, the hold process is performed; when the control execution condition is not met, the overwrite process is performed. as well as Based on the road surface arrow information after the coverage processing or the retention processing, determine whether the execution condition is met at the first time point.

6. A computer-readable, non-transitory recording medium containing a driving assistance program for use by a computer to execute: The step of enabling surrounding sensors to acquire road markings and intersection-related information existing in the area ahead as surrounding information, wherein the area ahead is the area including the road surface in front of the vehicle; If the specified execution conditions, including the detection of an intersection based on the surrounding information, are met, a step is executed to perform a driver assistance control that includes at least one of left and right turn deceleration assist control and left and right turn warning control. The left and right turn deceleration assist control automatically applies braking force to the vehicle in a manner that makes the vehicle's deceleration consistent with a target deceleration, thereby assisting the vehicle in decelerating to a specified target speed before making a right or left turn at the detected intersection. The left and right turn warning control alerts the driver of the vehicle, thereby prompting the driver to decelerate before making a right or left turn at the detected intersection. When a road surface arrow mark is detected on the lane in which the vehicle is traveling (i.e., the driving lane) based on the surrounding information, the step of associating information including the road surface arrow mark and the travelable direction of the driving lane indicated by it (i.e., road surface arrow information) with the detected intersection and storing it in a storage device. If, when any intersection is detected based on the surrounding information, the road surface arrow mark detected at any first time point is designated as the first road surface arrow mark, the road surface arrow information of the first road surface arrow mark is designated as the first road surface arrow information, and the road surface arrow information associated with the intersection detected at the first time point and already stored in the storage device is designated as the second road surface arrow information, then the step of determining whether the following specific condition is met is met when the number of directions other than the straight-ahead direction included in the travel direction of the driving lane indicated by the first road surface arrow mark is reduced compared to the number of directions other than the straight-ahead direction included in the travel direction of the driving lane included by the second road surface arrow information; If the specific conditions are not met, a coverage process is performed whereby the first road surface arrow information is used to cover the second road surface arrow information and the information is stored at the first time point. Under the specific conditions, Perform the process of maintaining the second road surface arrow information at the first time point, or The holding process is performed when the control execution condition, which is established while the driving assistance control is being executed, is met; the overriding process is performed when the control execution condition is not met. The step of determining whether the execution condition is met at the first time point based on the road surface arrow information after the coverage processing or the retention processing has been performed.

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