Road surface condition determination system, road surface condition determination device, vehicle driving control device, and road surface condition determination method

Abstract

A road surface state determination system (50) comprises: a distance measurement sensor (10) that is installed at a predetermined position of a vehicle X, projects light to a road surface in a measurement area in the surroundings of the vehicle X, receives reflected light of the projected light, and measures the distance to the road surface on the basis of a light-receiving state of the reflected light; and a determination unit (413) for determining that the road surface is wet when the reflected light has not been received by the distance measurement sensor (10) or when the measurement value by the distance measurement sensor is greater than a predetermined value.

Description

[Technical field]

[0001] The present disclosure relates to a road surface condition determination system, a road surface condition determination device, a vehicle driving control device, and a road surface condition determination method. [Background technology]

[0002] When a vehicle is traveling on a road and the road surface is wet due to rainfall, the coefficient of friction between the wheels and the road surface decreases, and the braking distance of the vehicle increases. In that case, the vehicle cannot stop in the intended position when braking, making safe driving difficult, so it is necessary to change the way you drive, such as reducing your driving speed or applying the brakes earlier. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-39311 A Summary of the Invention [Problem to be solved by the invention]

[0004] Autonomous vehicles monitor road conditions while driving, and when they detect that the road is wet, they take measures such as slowing down the vehicle's speed, ensuring safe driving.

[0005] In order to detect whether the road surface is wet, there are systems that are constructed by mounting devices dedicated to detecting road surface conditions, such as a camera device or a laser device that irradiates multiple laser beams (see Patent Document 1), on a vehicle. However, when such devices are newly mounted on a vehicle, there are problems in that the system configuration becomes complicated and the cost becomes high.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a road surface condition determination system, a road surface condition determination device, a vehicle driving control device, and a road surface condition determination method that are capable of detecting wet road surfaces with high accuracy using a simple configuration. [Means for solving the problem]

[0007] The road surface condition determination system of the present disclosure comprises a distance measurement sensor that is installed at a predetermined position on a vehicle, projects light toward the road surface in a measurement area around the vehicle, receives reflected light of the projected light, and measures the distance to the road surface based on the received state of the reflected light, and a determination unit that determines that the road surface is wet when the reflected light is not received by the distance measurement sensor or when the measurement value by the distance measurement sensor is longer than a predetermined value.

[0008] The ranging sensor may measure distances to multiple points on the road surface in the measurement area, and the determination unit may determine that the road surface is wet when the measurement area includes a partial area where the reflected light is not received by the ranging sensor, or when the measurement area includes a partial area where the measurement value is longer than a predetermined value.

[0009] The determination unit may determine that the road surface is wet when the number of measurement results regarding the reflected light of multiple light beams projected by the distance measuring sensor that are recognized as noise is equal to or greater than a predetermined value, and when the measurement area includes a partial area where the reflected light of the light projected by the distance measuring sensor is not received.

[0010] The distance measurement sensor may be an optical sensor for detecting an obstacle or an optical sensor for estimating the vehicle's own position that is installed in advance on the vehicle.

[0011] The vehicle may further include a reference data storage unit that stores as reference data information on the distance to the road surface for each position of the vehicle and each measurement direction measured by the ranging sensor when the vehicle or another vehicle is traveling on the road surface when the road surface is not wet, and the determination unit may determine that the road surface is wet when the measurement value of the distance to the road surface in the measurement direction measured by the ranging sensor at a specified position when the vehicle is traveling is longer than the distance to the road surface at a corresponding position and in the measurement direction in the reference data.

[0012] The reference data storage unit may temporarily store information on the position, time, and measurement value for each measurement direction of the vehicle or another vehicle measured by the distance measuring sensor while the vehicle or another vehicle is traveling, regardless of the wetness of the road surface, and the judgment unit may determine whether the road surface is wet or not for the location where the vehicle is scheduled to travel, using information on the measurement value measured by another vehicle within a specified period of time and stored in the reference data storage unit.

[0013] In addition, the road surface condition determination device of the present disclosure is installed at a predetermined position on a vehicle, projects light toward the road surface in a measurement area around the vehicle, receives reflected light of the projected light, and is connected to a distance measurement sensor that detects the distance to the road surface based on the received state of the reflected light.The road surface condition determination device is equipped with a determination unit that determines that the road surface is wet when the reflected light is not received by the distance measurement sensor or when the measurement value by the distance measurement sensor is longer than a predetermined value.

[0014] In addition, the vehicle driving control device according to the present disclosure includes an output unit that is connected to the road surface condition determination device and outputs an instruction to reduce the driving speed of the vehicle or stop the vehicle when the road surface condition determination device determines that the road surface is wet.

[0015] In addition, in the road surface condition determination method disclosed herein, a road surface condition determination device is installed at a predetermined position on a vehicle, projects light toward the road surface in a measurement area around the vehicle, receives reflected light of the projected light, and is connected to a distance measurement sensor that detects the distance to the road surface based on the received state of the reflected light.When the reflected light is not received by the distance measurement sensor or when the measurement value by the distance measurement sensor is longer than a predetermined value, the road surface condition determination device determines that the road surface is wet. Effect of the Invention

[0016] According to the road surface condition determination system, road surface condition determination device, vehicle driving control device, and road surface condition determination method disclosed herein, a wet road surface can be detected with high accuracy using a simple configuration. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a block diagram showing the configuration of an autonomous driving system using a road surface condition determination system according to an embodiment. [Diagram 2] FIG. 2(a) is a side view of a vehicle X equipped with a road surface condition determination system according to an embodiment, and the measurement direction of a distance measuring sensor installed on the vehicle X, and FIG. 2(b) is a top view of the measurement area of ​​the distance measuring sensor. [Diagram 3] FIG. 3 is a flowchart showing the operation of the road surface condition determining device according to the embodiment. [Figure 4] FIG. 4(a) is a diagram showing a state in which light projected from a distance measuring sensor installed on a vehicle X equipped with a road surface condition determination system according to an embodiment is reflected by a puddle on the road surface, and FIG. 4(b) is a diagram showing a state in which light projected from the distance measuring sensor is reflected by a puddle on the road surface and then reflected by the wall in front. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] (Configuration of Autonomous Driving System) A configuration of an autonomous driving system 1 using a road surface condition determination device according to an embodiment of the present disclosure will be described with reference to Fig. 1. The autonomous driving system 1 includes a distance measurement sensor 10, a position information detection sensor 20, an autonomous driving mechanism 30, and an in-vehicle device 40 mounted on an autonomously driven vehicle X.

[0019] The distance measurement sensor 10 is an optical sensor composed of LiDAR (Light Detection and Ranging) or the like. The distance measurement sensor 10 is installed in the front part of the vehicle X. For example, the distance measurement sensor 10 is installed in a predetermined position in the lower part of the front part of the vehicle X. The distance measurement sensor 10 projects light toward the road surface in the measurement area P around the vehicle X (i.e., in a predetermined direction (measurement direction)) and receives the reflected light of the projected light. Furthermore, the distance measurement sensor 10 measures the distance to the road surface based on the reception state of the reflected light. The measured distance is the length from the vehicle X (specifically, the distance measurement sensor 10) to a predetermined point (light irradiation position) on the road surface along the predetermined direction (measurement direction). Here, the light reception state is a measurement result indicating the measurement direction by the distance measurement sensor 10, the time from the emission of light by the distance measurement sensor 10 to the reception of the reflected light of the light, the intensity of the reflected light, etc. The optical sensor as the distance measurement sensor 10 may be, for example, an optical sensor for obstacle detection or self-position estimation that is pre-installed in the vehicle X. In this case, the automatic driving system 1 can be constructed without providing the vehicle X with a new device as the distance measuring sensor 10.

[0020] The position information detection sensor 20 is configured, for example, by a GPS (Global Positioning System) receiver, and acquires position information of the sensor 20 (substantially the vehicle X). The automatic driving mechanism 30 is a mechanism for automatically driving the vehicle X under the control of a driving control unit 42 described later.

[0021] The in-vehicle device 40 has a road surface condition determination device 41 and a driving control unit 42 as a vehicle driving control device. The road surface condition determination device 41 has a sensor information acquisition unit 411, a reference data storage unit 412, and a determination unit 413. Each of these functional units may be mounted on a processing device such as a computer (e.g., a personal computer). In this way, the processing device functions as the road surface condition determination device 41. Note that this processing device may be installed in advance in the vehicle X as a device that processes the detection results of the obstacle detection sensor or the self-position estimation sensor.

[0022] The sensor information acquisition unit 411 acquires information on the distance from the vehicle X to the road surface in the measurement area P measured by the distance measurement sensor 10, and acquires position information of the vehicle X detected by the position information detection sensor 20. The reference data storage unit 412 pre-stores, as reference data, information on the distance from the vehicle X to the road surface for each position of the vehicle X and for each measurement direction, which is measured by the distance measurement sensor 10 when the vehicle X travels in a predetermined section (expected travel section) on a dry road surface.

[0023] The determination unit 413 determines that the road surface is wet based on the information acquired by the sensor information acquisition unit 411 while the vehicle X is traveling when (a) the reflected light of the light projected by the distance measurement sensor 10 is not received by the distance measurement sensor 10, or (b) the distance measurement value by the distance measurement sensor 10 is longer than a predetermined value. In this embodiment, a road surface condition determination system 50 is constructed by the road surface condition determination device 41 and the distance measurement sensor 10.

[0024] When the determination unit 413 of the road surface condition determination device 41 determines that the road surface is wet, the driving control unit 42 outputs instructions to the automatic driving mechanism 30 to drive the vehicle X in a safer manner than during normal driving, such as reducing the driving speed or stopping the vehicle X. For example, the driving control unit 42 may include an output unit that outputs these instructions.

[0025] <Autonomous Driving System Operation> Next, a description will be given of an operation performed by the automatic driving system 1 according to this embodiment while the vehicle X is traveling. In this embodiment, while the vehicle X is traveling a predetermined section in automatic driving mode by the automatic driving mechanism 30, the distance measurement sensor 10 installed on the vehicle X measures the distance from the vehicle X (the distance measurement sensor 10) to the road surface in the measurement area around the vehicle X at predetermined time intervals.

[0026] As shown in FIG. 2(a), the distance measuring sensor 10 measures distances to a plurality of points on the road surface in the area surrounding the vehicle X based on the reception state of reflected light of light projected in a plurality of directions preset as measurement directions.

[0027] 2(b), the area into which the light of the distance measuring sensor 10 is projected is a measurement area P around the vehicle X including the forward and left and right directions when the vehicle X travels in the direction of the arrow. The distance measuring sensor 10 projects multiple lasers in different directions within the measurement area P, and measures the distance from the vehicle X to multiple points on the road surface within the measurement area P based on the reception state of the reflected light of the projected light.

[0028] Furthermore, while the vehicle X is traveling, the position information detection sensor 20 detects the position information of the sensor 20 (substantially the vehicle X) at predetermined time intervals.

[0029] An example of a process executed by the in-vehicle device 40 while the vehicle X is traveling will be described with reference to the flowchart in Fig. 3. When the vehicle X is traveling at a normal speed, the sensor information acquisition unit 411 acquires measurement result information by the distance measurement sensor 10 at a predetermined time interval, and also acquires position information of the position information detection sensor 20 detected by the sensor 20.

[0030] The determination unit 413 determines, based on the information acquired by the sensor information acquisition unit 411, whether or not the reflected light of the light projected from the distance measurement sensor 10 in multiple directions within the measurement area P has been received by the distance measurement sensor 10.

[0031] Here, it is assumed that the road surface where the light is projected from the distance measurement sensor 10 is wet. For example, as shown in FIG. 4(a), if there is a puddle W at the position where the light of the distance measurement sensor 10 is projected, the projected light is diffused by the upper surface of the puddle W. Therefore, the reflected wave does not reach the distance measurement sensor 10, or even if it does reach the distance measurement sensor 10, the intensity of the reflected wave is significantly attenuated, so that the distance measurement sensor 10 cannot substantially receive the reflected light (i.e., with an intensity within an expected range). In this way, when the measurement area P includes a partial area PA where the reflected light of the light projected by the distance measurement sensor 10 is not received by the distance measurement sensor 10 ("YES" in step S1), the determination unit 413 determines that the road surface indicated by the partial area PA is wet (step S2).

[0032] Furthermore, when it is determined that the partial area PA is not included in the measurement area P ("NO" in step S1), the determination unit 413 determines whether or not the partial area PB is included in the measurement area P (step S3). The partial area PB is an area in which the distance measurement value by the distance measuring sensor 10 is longer than the threshold value C.

[0033] When the road surface ahead of which light is projected from the distance measuring sensor 10 is wet and there is an obstacle ahead of the wet road surface, the light projected by the distance measuring sensor 10 is diffusely reflected by the wet road surface, reflected by the obstacle, and further reflected again by the wet road surface to be received by the distance measuring sensor 10.

[0034] 4(b), if there is a puddle W at the irradiation position of the light and a wall Q in front of it, the light will be diffused on the top surface of the puddle W, reflected by the wall Q, and then reflected again on the puddle W to be received by the distance measuring sensor 10. In this case, the distance measured by the distance measuring sensor 10 will be longer than the distance from the distance measuring sensor 10 to the road surface (the irradiation position, i.e., the puddle W).

[0035] Therefore, as shown in FIG. 2(b), if the partial area PB is included in the measurement area P ("YES" in step S3), the determination unit 413 determines that the road surface is wet (step S3). The threshold value C used in step S3 can be defined from various viewpoints. Below, the process of determining the road surface condition in step S3 based on several examples of the threshold value C will be described.

[0036] [Example of road surface condition determination process (1)] In the judgment process example (1), a threshold value C1 is used as the threshold value C. The threshold value C1 is the maximum value of the measurement distance from the vehicle X to the road surface that can be estimated based on the installation position and measurement direction of the distance measuring sensor 10 in the vehicle X, and the unevenness of the road surface. Based on the information acquired by the sensor information acquisition unit 411, if the partial area PB is included in the measurement area P, the judgment unit 413 judges that the road surface is wet. The threshold value C1 may be set to a different value for each measurement direction of the distance measuring sensor 10.

[0037] Here, the determination unit 413 determines that the partial area PB is included in the measurement area P if the positions on the road surface where the measurement value by the distance measurement sensor 10 is longer than the threshold C1 are adjacent to each other and the number of such positions is equal to or greater than a predetermined number D. This predetermined number D is set in advance as a value for detecting a wet state of the road surface that may affect the traveling of the vehicle X due to rainfall, for example. In this way, the distance measurement sensor 10 measures the distance from the vehicle X (distance measurement sensor 10) to multiple points on the road surface in the measurement area P, thereby making it possible to detect a wet state of the road surface that may affect the traveling of the vehicle X.

[0038] [Example of road surface condition determination process (2)] In the judgment process example (2), a threshold value C2 is used as the threshold value C. The threshold value C2 is a value obtained by adding a value E for absorbing measurement errors (in other words, for allowing an error in the measured value as the judgment criterion) to the distance indicated by the above-mentioned reference data stored in the reference data storage unit 412.

[0039] Then, based on the information acquired by the sensor information acquisition unit 411, the determination unit 413 determines that the road surface indicated by the partial area PB is wet if the partial area PB is included in the measurement area P. In other words, the determination unit 413 determines that the road surface is wet if the measurement value measured by the distance measuring sensor 10 at a certain position A while the vehicle X is traveling is longer than the distance to the corresponding position A in the reference data by a value E or more.

[0040] Specifically, the determination unit 413 acquires, over time, the information acquired by the sensor information acquisition unit 411 while the vehicle X is traveling, and the position information of the vehicle X at the time the information was acquired. Then, the determination unit 413 acquires, from the reference data stored in the reference data storage unit 412, information on the distance from the vehicle X to the road surface that corresponds to the position information and the measurement direction acquired by the determination unit 413.

[0041] Furthermore, when there are a predetermined number D or more of estimated far points adjacent to each other on the road surface, the determination unit 413 determines that the partial area PB is included in the measurement area P. Here, the estimated far point is a position where the measurement value measured by the distance measuring sensor 10 is longer than a threshold C2 obtained by adding a value E to the distance from the vehicle X to the road surface obtained from the reference data storage unit 412. When the determination unit 413 determines that the measurement area P includes the partial area PB, it determines that the road surface is wet.

[0042] Note that the determination unit 413 may execute steps S1 and S3 in the reverse order to the order shown in Fig. 3. Furthermore, the determination unit 413 may execute only one of steps S1 and S3.

[0043] When the determination unit 413 determines that the road surface is wet, the driving control unit 42 outputs an instruction to the automatic driving mechanism 30 to reduce the driving speed of the vehicle X below the normal speed (step S4). When the automatic driving mechanism 30 receives the instruction from the driving control unit 42, it reduces the traveling speed of the automatic driving.

[0044] Thereafter, when the road surface dries and the determination unit 413 determines that neither the partial areas PA nor PB is included in the measurement area P in a section of a distance equal to or greater than a predetermined value ("YES" in step S5), it determines that the road surface is dry (step S6). When the determination unit 413 determines that the road surface is dry, the driving control unit 42 outputs an instruction to the automatic driving mechanism 30 to return the driving speed of the vehicle to the normal speed (step S7). When the automatic driving mechanism 30 receives the instruction from the driving control unit 42, it returns the traveling speed of the automatic driving to the normal speed.

[0045] According to the above embodiment, a wet road surface can be detected with high accuracy based on the light receiving state of the light projected from the optical sensor. This allows the wet road surface detection process to be performed. Furthermore, when an optical sensor for obstacle detection or self-position estimation that is pre-installed in the vehicle X is used as the optical sensor of this embodiment, the above road surface condition can be detected at low cost without installing a new device for detecting the road surface condition in the vehicle.

[0046] The position information detection sensor 20 may be configured as a self-position estimation device using LiDAR. In that case, one self-position estimation device may have both the function of the distance measurement sensor 10 and the function of the position information detection sensor 20. The self-position estimation device estimates the current position of the device by, for example, performing scan matching between pre-stored map data and data acquired by an optical sensor.

[0047] The distance measuring sensor 10 may use multiple transmitting and receiving elements to measure distances from the vehicle X to the road surface at multiple positions within the measurement area P. In this case, if some of the transmitting and receiving elements fail, the distance measuring sensor 10 cannot obtain measurement results for the area measured by the failed transmitting and receiving element. In this case, even if the road surface is not wet, the partial area PA will be included in the measurement area P, so there is a risk that the determining unit 413 will determine that the road surface is wet.

[0048] On the other hand, when it rains, the light emitted from the distance measuring sensor 10 may be diffused by raindrops in the air, and the number of values ​​(positions) where the measurement results are recognized as noise that is not within the appropriate range tends to increase throughout the measurement area P of the measurement target. Therefore, when the number of measurement results (number of positions) recognized as noise by the distance measuring sensor 10 is equal to or greater than a predetermined value and the partial area PA is included in the measurement area P, the determination unit 413 may determine that the road surface is wet due to rain. This allows the distance measuring sensor 10 to detect a wet road surface with greater accuracy, excluding erroneous determinations due to failures of the transmitting and receiving elements.

[0049] The reference data stored in the reference data storage unit 412 may be reference data measured when another vehicle Y travels through the relevant section. In that case, the sensor information acquisition unit 411 of the road surface condition determination device 41 acquires the amount of deviation in the installation position and measurement direction of the distance measurement sensor between the vehicle Y that measures the reference data and the vehicle X that uses the reference data. Then, based on the acquired amount of deviation, the sensor information acquisition unit 411 converts the reference data measured by the distance measurement sensor of the vehicle Y into reference data to be used by the road surface condition determination device 41 of the vehicle X, and uses the converted data in the road surface condition determination process.

[0050] A central management device wirelessly connected to the on-board devices 40 of a plurality of vehicles including vehicle X may be installed, and the function of the reference data storage unit 412 may be provided in the central management device. In this case, the on-board device 40 of each vehicle wirelessly transmits information on the traveled position, distance, time, and installation position of the distance measuring sensor 10 in the corresponding vehicle, as well as information on the distance to the road surface in each measurement direction measured by the distance measuring sensor 10, to the central management device every time the vehicle travels on a wet road surface, and stores the information as reference data.

[0051] Then, the in-vehicle device 40 of the vehicle X acquires from the central management device the latest reference data measured by another vehicle Y or the vehicle X in the past for the location where the vehicle X is traveling. The sensor information acquisition unit 411 acquires the amount of deviation in the installation position and measurement direction of the distance measurement sensor between the vehicle that measured the acquired reference data and the vehicle X that uses the acquired reference data. Then, based on the acquired amount of deviation, the sensor information acquisition unit 411 converts the reference data acquired from the central management device into reference data to be used by the road surface condition determination device 41 of the vehicle X, and uses the converted data in the determination process of the road surface condition.

[0052] In this way, the reference data for the relevant positions is updated each time multiple vehicles travel, and each vehicle shares the latest reference data, making it possible to perform highly accurate determination processing even if the road shape, etc., changes.

[0053] In addition, the central management device may temporarily store information on the vehicle's position, time, and measurement value for each measurement direction measured by the distance measuring sensor while the vehicle is traveling in a reference data storage unit, regardless of the wetness of the road surface, and share and use this information among multiple vehicles. In this case, the determination unit 413 determines whether the road surface is wet or not for the position where the vehicle X is scheduled to travel, using information on the measurement values ​​measured by other vehicles within a predetermined time and stored in the reference data storage unit.

[0054] In this way, multiple vehicles can update the measurement values ​​for a given location each time they travel, and these values ​​can be used by other vehicles, allowing them to detect whether the road surface is wet or dry more quickly before traveling to that location, thereby improving driving efficiency.

[0055] In the above-described embodiment, when the determination unit 413 determines that the road surface is wet, the driving control unit 42 reduces the speed of the vehicle X below the normal speed. However, the driving control unit 42 may stop the vehicle X instead of decelerating the vehicle X. By reducing the speed of the vehicle X below the normal speed or stopping the vehicle X when it is determined that the road surface is wet, the vehicle X can be safely driven even when the road surface is slippery.

[0056] Although several embodiments have been described, the embodiments can be modified or modified based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually extracted and combined as long as they are not mutually inconsistent.

[0057] This disclosure can contribute, for example, to Sustainable Development Goal (SDG) Goal 11, "Make cities and human settlements inclusive, safe, resilient and sustainable." [Explanation of symbols]

[0058] 1. Autonomous Driving System 10 Distance sensor 20 Location information detection sensor 30 Automatic Driving Mechanism 40 Onboard equipment 41 Road surface condition determination device 42 Operation control unit 50 Road condition judgment system 411 Sensor information acquisition unit 412 Reference data storage unit 413 Judgment section

Claims

1. a distance measuring sensor that is installed at a predetermined position on the vehicle, projects light toward a road surface in a measurement area around the vehicle, receives reflected light of the projected light, and measures a distance to the road surface based on a state in which the reflected light is received; a determination unit that determines that the road surface is wet when the reflected light is not received by the distance measurement sensor or when a measurement value by the distance measurement sensor is longer than a predetermined value; A road surface condition determination system comprising:

2. The distance measuring sensor measures distances to a plurality of points on the road surface in the measurement area; 2. The road surface condition determination system of claim 1, wherein the determination unit determines that the road surface is wet when the measurement area includes a partial area in which the reflected light is not received by the distance measuring sensor, or when the measurement area includes a partial area in which the measurement value by the distance measuring sensor is longer than a predetermined value.

3. 3. The road surface condition determination system of claim 2, wherein the determination unit determines that the road surface is wet when a number of measurement results regarding the reflected light of multiple light beams projected by the distance measuring sensor that are recognized as noise is equal to or greater than a predetermined value, and when the measurement area includes a partial area in which the reflected light of the light projected by the distance measuring sensor is not received.

4. 2. The road surface condition determination system according to claim 1, wherein the distance measurement sensor is an optical sensor for detecting an obstacle or an optical sensor for estimating a vehicle's own position, the optical sensor being installed in advance on the vehicle.

5. a reference data storage unit that stores, as reference data, information on the distance to the road surface for each position of the vehicle and for each measurement direction, the distance to the road surface being measured by the distance measuring sensor when the vehicle or another vehicle is traveling on the road surface that is not wet; A road surface condition determination system as described in any one of claims 1 to 4, wherein the determination unit determines that the road surface is wet when the measurement value of the distance to the road surface in the measurement direction measured by the ranging sensor at a predetermined position when the vehicle is traveling is longer than the distance to the road surface in the measurement direction and at a corresponding position in the reference data.

6. the reference data storage unit temporarily stores information on the position of the vehicle, the time, and the measurement value for each measurement direction measured by the distance measuring sensor while the vehicle or another vehicle is traveling, regardless of the wetness of the road surface; 6. The road surface condition determination system according to claim 5, wherein the determination unit determines whether the road surface is wet or not using information on measurement values ​​measured by another vehicle within a predetermined time period and stored in the reference data storage unit for the location where the vehicle is scheduled to travel.

7. a distance measuring sensor that is installed at a predetermined position on the vehicle, projects light toward a road surface in a measurement area around the vehicle, receives reflected light of the projected light, and detects a distance to the road surface based on a reception state of the reflected light; A road surface condition determination device comprising a determination unit that determines that the road surface is wet when the reflected light is not received by the distance measuring sensor or when the measurement value by the distance measuring sensor is longer than a predetermined value.

8. 8. A vehicle driving control device comprising an output unit connected to the road surface condition determination device according to claim 7 and configured to output an instruction to reduce the driving speed of the vehicle or to stop the vehicle when the road surface condition determination device determines that the road surface is wet.

9. a road surface condition determination device that is installed at a predetermined position on the vehicle, projects light toward a road surface in a measurement area around the vehicle, receives reflected light of the projected light, and is connected to a distance measurement sensor that detects a distance to the road surface based on a received state of the reflected light; The road surface condition determining method determines that the road surface is wet when the reflected light is not received by the distance measuring sensor, or when the measurement value by the distance measuring sensor is longer than a predetermined value.

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