Roadside device and notification method

Abstract

The invention provides a roadside device and a notification method, which improve the technology of notifying pedestrians and vehicles of notice information. The roadside device (20) acquires a temporal distance from the autonomous vehicle (10) approaching the roadside device (20) to the roadside device (20) when a pedestrian facing the lane is detected from the image captured by the imaging unit (22), and transmits the pedestrian to the autonomous vehicle (10) when the acquired temporal distance is less than a threshold value determined in accordance with the external environment. A notification unit (21) notifies the autonomous vehicle (10) of first information indicating the presence of a pedestrian and / or notifies the pedestrian of second information indicating a restriction pertaining to crossing a lane.

Description

Technical Field

[0001] The present disclosure relates to a roadside device and a notification method. Background Art

[0002] Conventionally, there has been known a technology for notifying information to pedestrians and vehicles. For example, in Patent Document 1, there is disclosed a notification system that notifies vehicles and pedestrians other than the autonomous driving vehicle of whether passage is possible or attention information, etc., based on the behavior of the autonomous driving vehicle expected to pass through a prescribed traffic area.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2023-50629

[0004] However, in Patent Document 1, the idea of determining whether it is necessary to notify attention information based on the time distance between a pedestrian facing the lane and an autonomous driving vehicle approaching the pedestrian is not disclosed. Therefore, there is still room for improvement in the technology for notifying information to pedestrians and vehicles. Summary of the Invention

[0005] An object of the present disclosure completed in view of this situation is to improve the technology for notifying information to pedestrians and vehicles.

[0006] A roadside device according to one embodiment of the present disclosure includes a photographing unit, a notification unit, and a control unit. When the control unit detects a pedestrian facing the lane from an image photographed by the photographing unit, the control unit obtains the time distance from an autonomous driving vehicle approaching the roadside device to the roadside device. When the obtained time distance is less than a threshold value determined according to the external environment, the control unit notifies the autonomous driving vehicle of first information indicating the presence of the pedestrian and / or notifies the pedestrian of second information indicating a restriction related to crossing the lane via the notification unit.

[0007] A notification method according to one embodiment of the present disclosure is a notification method executed by a roadside device, including the following processes: when a pedestrian facing the lane is detected from a photographed image, obtaining the time distance from an autonomous driving vehicle approaching the roadside device to the roadside device; and when the obtained time distance is less than a threshold value determined according to the external environment, notifying the autonomous driving vehicle of first information indicating the presence of the pedestrian and / or notifying the pedestrian of second information indicating a restriction related to crossing the lane.

[0008] According to one embodiment of the present disclosure, the technology for notifying information to pedestrians and vehicles is improved. Brief Description of the Drawings

[0009] Figure 1It is a block diagram showing a schematic configuration example of a system according to one embodiment of the present disclosure.

[0010] Figure 2 It is a schematic diagram showing a configuration example of a roadside device.

[0011] Figure 3 It is a flowchart showing an operation example of a roadside device.

[0012] Figure 4 It is a schematic diagram for explaining a traffic area.

[0013] Explanation of reference numerals:

[0014] 1... System; 2... Network; 3... Lane; 4... Pedestrian; 5... Crosswalk; 6... Roadside strip; 10... Vehicle (autonomous vehicle); 11... Communication unit; 12... Positioning unit; 13... Measuring unit; 14... Input unit; 15... Output unit; 16... Storage unit; 17... Control unit; 20... Roadside device; 21... Notification unit; 211... Communication unit; 212... Output unit; 212A... Speaker; 212B... Display; 212C... Signal lamp; 22... Imaging unit; 22A... Camera; 23... Storage unit; 24... Control unit. Detailed implementation manners

[0015] Hereinafter, embodiments of the present disclosure will be described.

[0016] (Outline of the embodiment)

[0017] Refer to Figure 1 The outline of the system 1 according to the embodiment of the present disclosure will be described. The system 1 includes a vehicle 10 and a roadside device 20. The vehicle 10 and the roadside device 20 are connected to a network 2 including, for example, the Internet and a mobile communication network so as to be able to communicate.

[0018] The vehicle 10 is, for example, an automobile, but is not limited thereto, and may be any vehicle. The automobile is a gasoline vehicle, a BEV (Battery Electric Vehicle: pure electric vehicle), a HEV (Hybrid Electric Vehicle: hybrid electric vehicle), a PHEV (Plug-in Hybrid Electric Vehicle: plug-in hybrid electric vehicle), or an FCEV (Fuel Cell Electric Vehicle: fuel cell electric vehicle), etc., but is not limited to these. In the present disclosure, the vehicle 10 is an autonomous vehicle 10 having an autonomous driving function. However, the vehicle 10 is not limited to the autonomous vehicle 10. The number of autonomous vehicles 10 included in the system 1 can also be arbitrarily determined. The autonomous vehicle 10 is connected to the roadside device 20 via the network 2 so as to be able to communicate.

[0019] The roadside device 20 is an information communication device. When a pedestrian facing the lane is detected from the camera image, it notifies the pedestrian and also notifies the autonomous driving vehicle 10 approaching the pedestrian. The roadside device 20 is connected to the autonomous driving vehicle 10 via the network 2 so as to be able to communicate.

[0020] First, the outline of this embodiment will be described, and then it will be described in detail. When the roadside device 20 detects a pedestrian facing the lane from the image captured by the imaging unit 22, it obtains the time distance from the autonomous driving vehicle 10 approaching the roadside device 20 to the pedestrian. When the obtained time distance is less than the threshold determined according to the external environment, the first information indicating the presence of the pedestrian is notified to the autonomous driving vehicle 10 via the notification unit 21, and / or the second information indicating the restrictions related to crossing the lane is notified to the pedestrian.

[0021] In this way, according to this embodiment, when the time distance from the autonomous driving vehicle 10 to the roadside device 20 is less than the threshold, the autonomous driving vehicle 10 and / or the pedestrian is notified. Therefore, for example, even when the pedestrian enters the blind spot of the autonomous driving vehicle 10 and the visibility is poor, through the notification of the first information and / or the second information from the roadside device 20, the autonomous driving vehicle 10 can recognize the situation that the pedestrian wants to cross the lane, and the pedestrian can also recognize the situation that the autonomous driving vehicle 10 is approaching. Therefore, in terms of improving the probability of preventing traffic accidents, the technology of notifying information to pedestrians and vehicles has been improved.

[0022] Next, each structure of the system 1 will be described in detail.

[0023] (Structure of the vehicle)

[0024] As Figure 1 shown, the vehicle 10 (autonomous driving vehicle 10) includes a communication unit 11, a positioning unit 12, a measurement unit 13, an input unit 14, an output unit 15, a storage unit 16, and a control unit 17.

[0025] The communication unit 11 includes one or more communication interfaces connected to the network 2. This communication interface corresponds to, for example, mobile communication standards such as 4G (4th Generation) or 5G (5th Generation), or in-vehicle networks (such as CAN (Controller Area Network)), but is not limited to these. In this embodiment, the autonomous driving vehicle 10 communicates with the roadside device 20 via the communication unit 11 and the network 2.

[0026] The positioning unit 12 includes one or more devices that obtain the position information of the autonomous driving vehicle 10. Specifically, the positioning unit 12 includes, for example, a receiver corresponding to GPS, but is not limited thereto, and may also include a receiver corresponding to any satellite positioning system. The position information refers to the information of the latitude and longitude of the location that is the object.

[0027] The measurement unit 13 includes one or more devices that collect data inside and outside the autonomous driving vehicle 10. Specifically, the one or more devices are a pressure sensor, an exhaust gas sensor, an acceleration sensor, a gyro sensor, an ultrasonic sensor, a millimeter wave radar, an infrared radar, or a camera (in-vehicle camera), etc., which measure and collect data inside and outside the autonomous driving vehicle 10. However, the one or more devices are not limited to these. In addition, the ultrasonic sensor, the millimeter wave radar, the infrared radar, or the camera can also be used as a collision prevention sensor or a sensor for detecting obstacles.

[0028] The input unit 14 includes at least one input interface capable of receiving an input by a driver assistant of the autonomous driving vehicle 10. The input interface is, for example, a physical key, a capacitive key, a pointing device, a camera, a touch screen integrated with the display of the output unit 15 described later, or a microphone that picks up the voice of the driver assistant, etc. However, the input interface is not limited to these.

[0029] The output unit 15 includes at least one sound output interface capable of outputting sound, and at least one display interface capable of displaying text or images. The sound output interface is, for example, a speaker that outputs the first information indicating the presence of a pedestrian received from the roadside device 20 through sound. The display interface is, for example, a display such as an LCD or an organic EL display that outputs the first information indicating the presence of a pedestrian received from the roadside device 20 through text or images. However, the sound output interface and the display interface are not limited to these.

[0030] The storage unit 16 includes one or more memories. The memory is, for example, a semiconductor memory, a magnetic memory, or an optical memory, etc., but is not limited to these. Each memory included in the storage unit 16 can also function as a main storage device, an auxiliary storage device, or a cache memory, for example. The storage unit 16 stores any information for the operation of the autonomous driving vehicle 10. For example, the storage unit 16 can also store a system program, an application program, embedded software, and map information, etc. The information stored in the storage unit 16 can also be updated using the information obtained via the communication unit 11 from the network 2, for example.

[0031] The control unit 17 includes one or more processors, one or more programmable circuits, one or more dedicated circuits, or a combination thereof. The processor is, for example, a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor dedicated to specific processing, but is not limited to these. The programmable circuit is, for example, an FPGA (Field-Programmable Gate Array), but is not limited thereto. The dedicated circuit is, for example, an ASIC (Application Specific Integrated Circuit), but is not limited thereto. The control unit 17 controls the operation of the entire autonomous vehicle 10.

[0032] (Structure of roadside device)

[0033] Figure 2 is a schematic diagram showing an example of the structure of the roadside device 20. As Figure 1 and Figure 2 shown, the roadside device 20 includes a notification unit 21, a photographing unit 22, a storage unit 23, and a control unit 24.

[0034] The notification unit 21 functions as a communication unit 211 and an output unit 212.

[0035] The communication unit 211 includes one or more communication interfaces connected to the network 2. This communication interface corresponds to, for example, a mobile body communication standard, a wired LAN (Local Area Network) standard, or a wireless LAN standard, but is not limited to these, and may correspond to any communication standard. In the present embodiment, the roadside device 20 communicates with the autonomous vehicle 10 via the communication unit 211 and the network 2.

[0036] The output unit 212 includes at least one sound output interface capable of outputting sound, at least one display interface capable of displaying text or images, and at least one light emitting interface capable of emitting light, etc. The sound output interface is, for example, a speaker 212A that notifies a pedestrian of second information indicating restrictions related to crossing a lane by sound. The display interface is, for example, a display 212B such as an LCD or an organic EL display provided on the roadside strip of a lane that notifies a pedestrian of second information indicating restrictions related to crossing a lane by text or images, etc. The light emitting interface is, for example, a signal lamp 212C that notifies a pedestrian of the approach of the autonomous vehicle 10 by flashing light. The second information may also be notified to a pedestrian by using at least two of the speaker 212A, the display 212B, and the signal lamp 212C simultaneously.

[0037] The imaging unit 22 is equipped with a camera 22A and captures a moving image or a still image of a pedestrian facing the lane.

[0038] The storage unit 23 includes one or more memories. Each memory included in the storage unit 23 can function as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage unit 23 stores any information for the operation of the roadside device 20. For example, the storage unit 23 can store a system program, an application program, a database, and images captured by the imaging unit 22. The information stored in the storage unit 23 can be updated, for example, using information obtained via the communication unit 211 from the network 2.

[0039] The control unit 24 includes one or more processors, one or more programmable circuits, one or more dedicated circuits, or a combination thereof. The control unit 24 controls the overall operation of the roadside device 20.

[0040] (Operation flow of the roadside device)

[0041] Refer to Figure 3 The operation of the roadside device 20 according to this embodiment will be described. This operation is related to the notification of information about pedestrians and the autonomous vehicle 10.

[0042] Figure 4 It is a schematic diagram for explaining the traffic area. As Figure 4 shown, the autonomous vehicle 10 travels in the lane 3, and the pedestrian 4 crosses the lane 3 at a crosswalk 5 or the like. The roadside device 20 can be installed at any location. In Figure 4 the example shown, the roadside device 20 is installed, for example, on the roadside strip of the lane 3 near the crosswalk 5.

[0043] S101: The control unit 24 detects a pedestrian facing the lane from the image captured by the imaging unit 22.

[0044] The imaging unit 22 captures a moving image or a still image of the pedestrian 4 facing the lane 3 through the camera 22A.

[0045] S102: The control unit 24 obtains the time distance Td from the autonomous vehicle 10 approaching the roadside device 20 to the roadside device 20.

[0046] The so-called time distance Td (Time distance) is not the spatial distance that represents the distance from a certain location to other locations in terms of several kilometers, but the time distance expressed by the time (seconds) required for movement. For example, the time distance Td is the time such as 2 seconds (2 sec) required for the autonomous driving vehicle 10 to move to the location where the roadside device 20 is set. The control unit 24 receives, from the autonomous driving vehicle 10 via the communication unit 211 and the network 2, the position information L1(x1, y1) of the autonomous driving vehicle 10 located by the positioning unit 12 and the vehicle speed S measured by the measuring unit 13. If the position information of the roadside device 20 is set as L2(x2, y2), the distance D between the autonomous driving vehicle 10 and the roadside device 20 is calculated by the following formula (1), and the time distance Td is calculated based on formula (2).

[0047] D 2 =(x1 - x2) 2 +(y1 - y2) 2 (1)

[0048] Td = D / S (2)

[0049] S103: The control unit 24 determines whether the obtained time distance Td is less than the threshold α determined according to the external environment.

[0050] The external environment is, for example, weather, illuminance, time period, the number or congestion degree of other vehicles in lane 3, the number of pedestrians 4 detected from the image of the roadside device 20, and the number of obstacles around the roadside device 20, but the external environment is not limited to these.

[0051] S104 - S105: When the obtained time distance Td is less than the threshold α, the control unit 24 notifies the autonomous driving vehicle 10 of the first information indicating the presence of the pedestrian 4 via the notification unit 21, and / or notifies the pedestrian 4 of the second information indicating the restrictions related to crossing the lane 3.

[0052] Explain the meaning of "and / or". That is, when the obtained time distance Td is less than the threshold α, the control unit 24 performs any one of the following (i), (ii), and (iii) via the notification unit 21, namely: (i) notifies the autonomous driving vehicle 10 of the first information indicating the presence of the pedestrian 4; (ii) notifies the pedestrian 4 of the second information indicating the restrictions related to crossing the lane 3; and (iii) notifies the autonomous driving vehicle 10 of the first information indicating the presence of the pedestrian 4 and notifies the pedestrian 4 of the second information indicating the restrictions related to crossing the lane 3.

[0053] The control unit 24 sets the threshold α (sec) based on at least one of the following (i) to (vi). The control unit 24 may adopt a specific threshold α among (i) to (vi), or may adopt the maximum threshold α among (i) to (vi).

[0054] (i) When the weather is rainy, cloudy or foggy, a threshold α with a value larger than that in sunny weather can be set. For example, the control unit 24 may also be such that when the weather is rainy, the threshold α is set to α = 3 sec, and when the weather is sunny, the threshold α is set to α = 2 sec. In rainy weather, the visibility is worse than in sunny weather, so it is necessary to notify the first information to the autonomous driving vehicle 10 and the second information to the pedestrian 4 in advance.

[0055] (ii) When the illuminance is less than the reference value, a threshold α with a value larger than that when the illuminance is equal to or higher than the reference value can be set. Illuminance is a physical quantity representing the brightness of light illuminating the surface of an object, and the unit of illuminance is expressed in lux (lx). For example, it may also be that when the illuminance during the day on a cloudy day (e.g., 32,000 lx) is used as the reference value, when the illuminance is less than 32,000 lx, the threshold α = 3 sec, and when the illuminance is 32,000 lx or higher, the threshold α = 2 sec. If the illuminance is lower than the reference value, the visibility deteriorates, so it is necessary to notify the first information to the autonomous driving vehicle 10 and the second information to the pedestrian 4 in advance.

[0056] (iii) When the time period is at night, a threshold α with a value larger than that during the day can be set. For example, the control unit 24 may also set the threshold α at night to α = 5 sec and the threshold α during the day to α = 2 sec. At night, the visibility is worse than during the day, so it is necessary to notify the first information to the autonomous driving vehicle 10 and the second information to the pedestrian 4 in advance.

[0057] (iv) When the number or congestion level of other vehicles in lane 3 is less than the reference value, a threshold α with a value larger than that when the number or congestion level of other vehicles in lane 3 is equal to or higher than the reference value can be set. For example, when the number of vehicles traveling in a specified area is less than the reference value, or when the congestion level is less than the reference value, compared with when it is equal to or higher than the reference value, the autonomous driving vehicle 10 can travel at a higher speed. Therefore, when the number or congestion level of other vehicles in lane 3 is less than the reference value, compared with when it is equal to or higher than the reference value, it is necessary to notify the first information to the autonomous driving vehicle 10 and the second information to the pedestrian 4 in advance.

[0058] (v) When the number of pedestrians 4 detected from the image of the roadside device 20 is equal to or greater than the reference value, a threshold value α greater than the value set when the number of pedestrians 4 detected from the image of the roadside device 20 is less than the reference value can be set. When the number of pedestrians 4 is equal to or greater than the reference value, the risk of pedestrians 4 suddenly entering the lane 3 increases. Therefore, it is necessary to notify the first information to the autonomous driving vehicle 10 in advance and notify the second information to the pedestrians 4.

[0059] (vi) When the number of obstacles around the roadside device 20 is equal to or greater than the reference value, a threshold value α greater than the value set when the number of obstacles around the roadside device 20 is less than the reference value can be set. An obstacle refers to, for example, a tree, a utility pole, or a building structure. When the number of obstacles around the roadside device 20 is equal to or greater than the reference value, the visibility deteriorates. Therefore, it is necessary to notify the first information to the autonomous driving vehicle 10 in advance and notify the second information to the pedestrians 4.

[0060] According to this structure, in an environment with relatively poor visibility such as at night or in rainy weather, by making the threshold value α greater than the value in normal times (during the day or on a sunny day), when the autonomous driving vehicle 10 is located at a position farther from the roadside device 20, notifications to the autonomous driving vehicle 10 and / or the pedestrians 4 are made, thereby improving traffic safety.

[0061] The control unit 24 may also set two or more threshold values α. For example, the control unit 24 may set a first threshold value α1 and a second threshold value α2 that is greater than the first threshold value α1. When the time distance Td is less than the first threshold value α1, a corresponding message that prompts a higher level of urgency than when the time distance Td is equal to or greater than the first threshold value α1 and less than the second threshold value α2 is notified to the autonomous driving vehicle 10 as the first information via the notification unit 21, and / or the message is notified to the pedestrians 4 as the second information.

[0062] The meaning of "and / or" is explained. That is, when the time distance Td is less than the first threshold value α1, the control unit 24 performs any one of the following (i), (ii), and (iii) via the notification unit 21: (i) notifying a corresponding message that prompts a higher level of urgency to the autonomous driving vehicle 10 as the first information; (ii) notifying the message to the pedestrians 4 as the second information; and (iii) notifying the message to the autonomous driving vehicle 10 as the first information and notifying the message to the pedestrians 4 as the second information.

[0063] The control unit 24 may also, when the time distance Td is equal to or greater than the first threshold α1 and less than the second threshold α2, notify the corresponding messages that prompt a low level of urgency (weak warning), such as "There is a pedestrian" or "Please cross while paying attention to the autonomous driving vehicle", etc., as the first information and the second information, to the autonomous driving vehicle 10 and the pedestrian 4. On the other hand, the control unit 24 may also, when the time distance Td is less than the first threshold α1, notify the corresponding messages that prompt a higher level of urgency (strong warning), such as "Watch out for pedestrians rushing out" or "No crossing allowed", etc., as the first information and the second information, to the autonomous driving vehicle 10 and the pedestrian 4. According to this notification, the autonomous driving vehicle 10 and the pedestrian 4 can respond according to the situation based on the level of urgency.

[0064] The output unit 212 includes, for example, a signal lamp 212C that notifies the pedestrian of the approach of the autonomous driving vehicle 10 by flashing light. The control unit 24 may also, when the time distance Td is less than the first threshold α1, cause the signal lamp 212C to flash at a high speed, and when the time distance Td is equal to or greater than the first threshold α1 and less than the second threshold α2, cause the signal lamp 212C to flash at a lower speed. However, other methods such as changing the color of the light may also be used as the method of flashing the signal lamp according to the level of urgency.

[0065] The probability of the autonomous driving vehicle 10 avoiding a traffic accident by decelerating or stopping when receiving a notification such as "Watch out for pedestrians rushing out" from the roadside device 20 is increased. In addition, the driver assistance personnel riding in the autonomous driving vehicle 10 may also receive a notification such as "Watch out for pedestrians rushing out" output by sound, text, or image from the speaker or display included in the output unit 15 of the autonomous driving vehicle 10, and manually decelerate or stop the autonomous driving vehicle 10.

[0066] As described above, when the roadside device 20 according to the present embodiment detects a pedestrian 4 facing the lane 3 from the image of the imaging unit 22, it obtains the time distance Td from the autonomous driving vehicle 10 approaching the roadside device 20 to the roadside device 20, and when the obtained time distance Td is less than the threshold α determined according to the external environment, notifies the autonomous driving vehicle 10 of the first information indicating the presence of the pedestrian 4 via the notification unit 21, and / or notifies the pedestrian 4 of the second information indicating the restriction related to crossing the lane 3.

[0067] According to this structure, when the time distance Td from the autonomous vehicle 10 to the roadside device 20 is less than the threshold value α, notification to the autonomous vehicle 10 and / or the pedestrian 4 is performed. Thus, for example, even when the pedestrian 4 enters the blind spot of the autonomous vehicle 10 and visibility is poor, through the notification of the first information and / or the second information from the roadside device 20, the autonomous vehicle 10 can recognize the situation that the pedestrian 4 wants to cross the lane 3, and the pedestrian 4 can recognize the situation that the autonomous vehicle 10 is approaching. Therefore, in terms of improving the probability of preventing traffic accidents, the technology of notifying the pedestrian 4 and the vehicle 10 of caution information has been improved.

[0068] The present disclosure has been described based on the respective drawings and embodiments, but it should be noted that those skilled in the art can also make various modifications and changes based on the present disclosure. Therefore, it should be noted that these modifications and changes are included in the scope of the present disclosure. For example, the functions and the like included in each structural part or each step can be reconfigured in a logically non-contradictory manner, and a plurality of structural parts or steps can be combined into one or divided. For example, in the above-described embodiment, there may also be an embodiment in which the structure and operation of the roadside device 20 are distributed among a plurality of roadside devices capable of communicating with each other.

[0069] In addition, for example, there may also be an embodiment in which a general-purpose computer functions as the roadside device 20 according to the above-described embodiment. Specifically, a program describing the processing contents for realizing the respective functions of the roadside device 20 according to the above-described embodiment is stored in the memory of the general-purpose computer, and the processor reads and executes this program. Therefore, the present disclosure can also be realized as a program executable by a processor or a non-transitory computer-readable medium storing this program.

Claims

1. A roadside device, comprising a photographing unit, a notification unit and a control unit, wherein: The control unit acquires a time distance from the autonomous driving vehicle approaching the roadside device to the roadside device when a pedestrian heading toward the lane is detected from the image captured by the imaging unit, When the acquired time distance is less than a threshold value determined according to the external environment, the first information indicating the presence of the pedestrian is notified to the autonomous driving vehicle via the notification unit, and / or the second information indicating restrictions related to crossing the lane is notified to the pedestrian.

2. The roadside device according to claim 1, wherein: The external environment is weather, illumination, time period, the number of other vehicles in the lane or the degree of congestion, the number of pedestrians detected from the image of the roadside device, and the number of obstacles around the roadside device.

3. The roadside device according to claim 2, wherein: When the weather is rainy, cloudy or foggy, the control unit sets a threshold value larger than that when the weather is sunny. The control unit sets a threshold value greater than a value when the illuminance is greater than a reference value when the illuminance is less than a reference value. The control unit sets the threshold value to a larger value than that in the daytime when the time period is nighttime, The control unit sets a threshold value greater than a value when the number of other vehicles on the lane or the congestion level is greater than a reference value when the number of other vehicles on the lane or the congestion level is less than a reference value. When the number of pedestrians detected from the image of the roadside device is greater than a reference value, the control unit sets a threshold value that is greater than a value when the number of pedestrians detected from the image of the roadside device is less than the reference value. The control unit sets a threshold value having a larger value when the number of obstacles around the roadside device is equal to or larger than a reference value than when the number of obstacles around the roadside device is less than the reference value.

4. The roadside device according to claim 1, wherein: The control unit sets a first threshold and a second threshold which is a value greater than the first threshold, and when the time distance is less than the first threshold, the control unit notifies the autonomous driving vehicle as the first information via the notification unit, prompting the pedestrian to take a corresponding message which is more urgent than when the time distance is greater than the first threshold and less than the second threshold, and / or notifies the pedestrian as the second information.

5. A notification method is a notification method performed by a roadside device, wherein: This includes the following processing, namely: When a pedestrian heading toward the lane is detected from the captured image, obtaining a time distance from the autonomous driving vehicle approaching the roadside device to the roadside device; as well as When the obtained time distance is less than a threshold value determined according to the external environment, the first information indicating the presence of the pedestrian is notified to the autonomous driving vehicle, and / or the second information indicating restrictions related to crossing the lane is notified to the pedestrian.

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