Road surface evaluation device

Abstract

To recognize a road surface situation before skid occurs on a snowy road and the like.SOLUTION: A road surface evaluation device 10 comprises: an information acquisition unit 111 that acquires travel information including positional information indicating a travel position of each of a plurality of vehicles traveling on a road, and acceleration information indicating an acceleration of each of the plurality of vehicles; a storage unit 120 that stores first road surface information indicating a surface roughness of a road during a first predetermined period; a calculation unit 112 that generates second road surface information indicating a surface roughness of a road in a second predetermined period subsequent to the first predetermined period based on travel information of the plurality of vehicles acquired by the information acquisition unit 111 in the second predetermined period; a determination unit 113 that determines whether a road has a specific road surface property based on the second road surface information generated by the calculation unit 112, and that determines whether or not a snow accumulation has occurred on the road based on a difference between the first road surface information and the second road surface information if the determination unit determines that the road has the specific road surface property; and an output unit 114 that outputs snow accumulation information including a determination result from the determination unit 113.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a road surface evaluation device for evaluating the condition of a road surface. [Background technology]

[0002] A known example of this type of device is one that monitors road surface conditions in a target area based on information indicating whether or not drive wheel slip has occurred, obtained from multiple vehicles traveling on roads in the target area (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4737853 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the device described in Patent Document 1 monitors the road surface condition based on the presence or absence of slippage, it is difficult to monitor the road surface condition before slippage occurs on snowy roads or the like. [Means for solving the problem]

[0005] A road surface evaluation device according to one embodiment of the present invention includes a driving information acquisition unit that acquires driving information including position information indicating the driving position and acceleration information indicating the acceleration of each of a plurality of vehicles traveling on a road; a memory unit that stores first road surface information indicating the roughness of the road surface during a first predetermined period; a generation unit that generates second road surface information indicating the roughness of the road surface during a second predetermined period based on the driving information of the plurality of vehicles acquired by the driving information acquisition unit during a second predetermined period after the first predetermined period; a road surface determination unit that determines whether or not the road has specific road surface characteristics based on the second road surface information generated by the generation unit; a snow accumulation determination unit that determines whether or not snow has accumulated on the road based on the difference between the first road surface information and the second road surface information when the road surface determination unit determines that the road has specific road surface characteristics; and an output unit that outputs snow accumulation information including the determination result of the snow accumulation determination unit. Effect of the Invention

[0006] According to the present invention, road surface conditions can be recognized before slippage occurs on snowy roads or the like. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of the configuration of a road surface evaluation system including a road surface evaluation device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a configuration of a main part of the in-vehicle device. [Diagram 3] FIG. 2 is a block diagram showing the configuration of a main part of a driving information storage device. [Figure 4] 1 is a block diagram showing a configuration of a main part of a road surface evaluation device according to an embodiment of the present invention. [Diagram 5] FIG. 2 is a diagram showing an example of a map of roads on which a vehicle travels. [Figure 6] FIG. 4 is a diagram showing an example of travel information. [Figure 7] FIG. 4 is a diagram showing an example of combined travel information. [Figure 8A] FIG. 4 is a diagram for explaining a method of deriving the correlation between a road surface roughness value and a lateral acceleration. [Figure 8B] FIG. 4 is a diagram for explaining a method of deriving the correlation between a road surface roughness value and a lateral acceleration. [Figure 9] FIG. 4 is a diagram showing an example of road surface profile information. [Figure 10] 5 is a flowchart showing an example of processing executed by a calculation unit in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 10. A road surface evaluation device according to an embodiment of the present invention is a device for evaluating a road surface profile of a road on which a vehicle travels. Fig. 1 is a diagram showing an example of the configuration of a road surface evaluation system including a road surface evaluation device according to this embodiment. As shown in Fig. 1, the road surface evaluation system 1 includes a road surface evaluation device 10, an in-vehicle terminal 30, and a travel information storage device (hereinafter simply referred to as a storage device) 40. The road surface evaluation device 10 and the storage device 40 are configured, for example, by a server device. The in-vehicle terminal 30 is configured to be able to communicate with the road surface evaluation device 10 and the storage device 40 via a communication network 2.

[0009] The communication network 2 includes not only public wireless communication networks such as the Internet and mobile phone networks, but also closed communication networks established for each designated management area, such as wireless LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), etc.

[0010] The in-vehicle terminal 30 is mounted on a vehicle 20. The vehicles 20 include a plurality of vehicles 20-1, 20-2, . . . , 20-n. The vehicles 20 may be manually driven vehicles or automatically driven vehicles. The vehicles 20 may include vehicles of different models and grades.

[0011] 2 is a block diagram showing the main configuration of the in-vehicle terminal 30 according to this embodiment. The in-vehicle terminal 30 includes an electronic control unit (ECU) 31, a positioning sensor 32, an acceleration sensor 33, a steering angle sensor 34, a vehicle speed sensor 35, and a TCU (Telematic Control Unit) 36.

[0012] The positioning sensor 32 is, for example, a GPS sensor that receives a positioning signal transmitted from a GPS satellite and detects the absolute position (latitude, longitude, etc.) of the vehicle 20. The positioning sensor 32 includes not only a GPS sensor but also a sensor that performs positioning using radio waves transmitted from satellites of various countries called GNSS satellites, including quasi-zenith orbit satellites.

[0013] The acceleration sensor 33 detects acceleration in the left-right direction, i.e., lateral acceleration, of the vehicle 20. The acceleration sensor 33 may be configured to detect acceleration in the front-rear direction and acceleration in the up-down direction as well as the lateral acceleration of the vehicle 20. The steering angle sensor 34 detects the steering angle of a steering wheel (not shown) of the vehicle 20. The vehicle speed sensor 35 detects the vehicle speed of the vehicle 20.

[0014] 2, the ECU 31 includes a computer having a calculation unit 310 such as a CPU, a storage unit 320 such as a ROM, a RAM, and other peripheral circuits (not shown) such as an I / O interface. The calculation unit 310 functions as a sensor value acquisition unit 311 and a communication control unit 312 by executing a program stored in advance in the storage unit 320.

[0015] The sensor value acquisition unit 311 acquires the detection values ​​of the sensors 33-35 and the absolute position of the vehicle 20 detected by the positioning sensor 32 at a predetermined period. The communication control unit 312 transmits the information acquired by the sensor value acquisition unit 311 (hereinafter referred to as traveling information) together with a vehicle ID capable of identifying the vehicle 20 to the communication network 2 via the TCU 36 at a predetermined period.

[0016] 3 is a block diagram showing the main configuration of the storage device 40 according to this embodiment. The storage device 40 includes a computer having a calculation unit 41 such as a CPU, a storage unit 42 such as a ROM and a RAM, a communication unit 43, and other peripheral circuits (not shown) such as an I / O interface. The calculation unit 41 functions as an information receiving unit 411 by executing a program stored in the storage unit 42. The communication unit 43 is a communication interface that connects the storage device 40 to the communication network 2.

[0017] The information receiving unit 411 receives, via the communication unit 43, travel information transmitted from the in-vehicle terminal 30 of each vehicle 20 traveling on a road. The travel information includes position information indicating the position of the vehicle 20, travel time information indicating the time when the vehicle 20 traveled through that position, and acceleration information indicating the acceleration of the vehicle 20. The acceleration information includes information on the lateral acceleration of the vehicle 20 detected by the acceleration sensor 33. The travel information also includes travel speed information indicating the travel speed of the vehicle 20. The travel speed information indicates the sensor value of the vehicle speed sensor 35, i.e., the measured value of the travel speed of the vehicle 20. The travel information also includes steering angle information indicating the steering angle of the steering wheel of the vehicle 20. The steering angle information indicates the sensor value of the steering angle sensor 34, i.e., the measured value of the steering angle of the vehicle 20. The vehicle ID accompanying the travel information makes it possible to identify the vehicle 20 that is the source of the travel information.

[0018] The information receiving unit 411 stores the travel information received from the multiple vehicles 20 (vehicle-mounted terminals 30) in chronological order in the storage unit 120. Hereinafter, the travel information stored in chronological order in the storage unit 120 will be referred to as time-series travel information.

[0019] 4 is a block diagram showing the main configuration of the road surface evaluation device 10 according to this embodiment. The road surface evaluation device 10 detects the uneven shape of the road surface, i.e., the roughness of the road surface (hereinafter also referred to as the road surface profile), based on the travel information of a plurality of vehicles 20 stored in a storage device 40, specifically, the acceleration information. This detected road surface profile information is output to a terminal owned by a road management company or the like, and is used as reference data when the road management company or the like considers the necessity of repairs, etc. In other words, the acceleration information is used to evaluate the road surface profile.

[0020] The road surface evaluation device 10 includes a computer having a calculation unit 110 such as a CPU, a storage unit 120 such as a ROM, a RAM, a communication unit 13, and other peripheral circuits (not shown) such as an I / O interface. The storage unit 120 stores map information including a road map and various information processed by the calculation unit 110. The communication unit 13 is a communication interface that connects the road surface evaluation device 10 to a communication network 2.

[0021] The calculation unit 110 executes a program stored in the storage unit 120 to function as an information acquisition unit 111 , a calculation unit 112 , a determination unit 113 , and an output unit 114 .

[0022] The information acquisition unit 111 acquires from the storage device 40 via the communication unit 13 the travel information of the vehicles 20 corresponding to the period (hereinafter referred to as the evaluation period) and road (hereinafter referred to as the evaluation road) to be evaluated for road surface roughness. The evaluation period and the evaluation road are specified by an output instruction for a road surface profile, which will be described later. FIG. 5 is a diagram showing an example of a map of the road on which the vehicle 20 travels. In FIG. 5, the section (latitude Y to Z of National Route X) designated as the evaluation road is shaded with diagonal lines. In FIG. 5, the upward direction corresponds to the north direction, and the rightward direction corresponds to the east direction. When the evaluation road has multiple lanes on one side, the lane to be evaluated for road surface roughness may be specified by the user. In addition, the information acquisition unit 111 acquires map information including information on the evaluation road from the storage unit 120.

[0023] The calculation unit 112 calculates a road surface roughness value indicating the amount of unevenness (depth or height) of the road surface of the evaluation target road, that is, the road surface roughness, based on the travel information of the multiple vehicles 20 corresponding to the evaluation target road and the evaluation target period acquired by the information acquisition unit 111. More specifically, the calculation unit 112 calculates the road surface roughness value based on the evaluation target period and the lateral acceleration of the multiple vehicles 20 corresponding to the evaluation target road. The road surface roughness value may be expressed, for example, by IRI (International Roughness Index), which is an international index, or may be expressed by a value correlated with IRI. Hereinafter, the road surface roughness value may be simply expressed as a roughness value.

[0024] Fig. 6 is a diagram showing an example of time-series travel information acquired by the road surface evaluation device 10 from the in-vehicle terminal 30 of the vehicle 20 traveling on the evaluation target road (latitude Y to Z of national highway X) in Fig. 5. The horizontal axis in the diagram represents the position (latitude) of the vehicle 20 in the traveling direction along the travel lane, and the vertical axis represents the lateral acceleration of the vehicle 20. Characteristics D1, D2, ..., Dn represent the time-series travel information of the vehicles 20-1, 20-2, ..., 20-n, respectively.

[0025] Fig. 7 is a diagram showing an example of composite travel information generated based on travel information acquired from the in-vehicle terminals 30 of multiple vehicles 20 traveling on the road in Fig. 5. The composite travel information is information obtained by combining acceleration information of each vehicle 20 based on position information of each vehicle 20. The composite travel information shown in Fig. 7 is obtained by overlapping the vertical axis (lateral acceleration) values ​​of each vehicle 20 shown in Fig. 6 based on the horizontal axis (latitude). The calculation unit 112 calculates the road surface roughness value of the road on which each vehicle 20 is traveling based on the composite travel information obtained in this manner.

[0026] In general, the greater the amount of unevenness on the road surface, the greater the lateral acceleration of the vehicle 20, and there is a predetermined correlation between the road surface roughness value and the lateral acceleration. The calculation unit 112 uses information indicating this correlation (hereinafter referred to as correlation data) to calculate the road surface roughness value corresponding to the vehicle position on the road from the lateral acceleration.

[0027] First, the calculation unit 112 performs machine learning using previously measured road surface roughness values ​​and lateral acceleration as teacher data, and calculates the correlation between the road surface roughness value and the lateral acceleration. FIG. 8A and FIG. 8B are diagrams for explaining teacher data of road surface roughness values ​​and lateral acceleration, respectively. The vehicle V1 shown in FIG. 8A is a dedicated vehicle equipped with a measuring device MA for measuring road surface roughness. The measuring device MA measures the road surface roughness value of the road RD when the vehicle V1 is traveling on a predetermined road (measurement course, etc.) RD. The characteristic P1 in FIG. 8A indicates the road surface roughness value measured at this time, that is, the road surface roughness value used as teacher data.

[0028] Fig. 8B shows a state in which vehicle 20 in Fig. 1 travels on the same road RD as in Fig. 8A. A characteristic P2 in Fig. 8B shows the lateral acceleration detected by acceleration sensor 33 provided on vehicle 20 while vehicle 20 is traveling on a predetermined road RD, that is, the lateral acceleration used as teacher data.

[0029] The teacher data of the road surface roughness value and the lateral acceleration may be stored in the memory unit 120 of the road surface evaluation device 10, or may be stored in an external storage device. The calculation unit 112 performs machine learning using the teacher data of the road surface roughness value and the lateral acceleration read from the memory unit 120 or the external storage device, and calculates the correlation between the road surface roughness value and the lateral acceleration. Note that the machine learning may be performed by adding the traveling speed, the longitudinal acceleration, and the steering angle as the teacher data.

[0030] The calculation unit 112 calculates a road surface roughness value of the road to be evaluated based on the correlation between the calculated road surface roughness value and the lateral acceleration and the combined driving information corresponding to the road to be evaluated. The calculation unit 112 further generates information (hereinafter referred to as road surface profile information or road surface information) that associates the calculated road surface roughness value of the road to be evaluated with the road information acquired by the information acquisition unit 111, and stores the generated road surface profile information in the storage unit 120.

[0031] The determination unit 113 determines whether or not snow has accumulated on the road to be evaluated, based on the road surface profile information of the road to be evaluated read from the storage unit 120. The determination unit 113 will be described in detail later.

[0032] The output unit 114 outputs the road surface profile information. When the output unit 114 receives an output instruction of the road surface profile from a terminal of a road management company or the like via the communication network 2, the output unit 114 outputs the road surface profile information to the terminal that sent the output instruction or the terminal of a predetermined output destination. More specifically, when the output unit 114 receives the output instruction, the information acquisition unit 111 acquires the travel information of the multiple vehicles 20 corresponding to the evaluation target period and the evaluation target road designated in the output instruction from the storage device 40 via the communication unit 13. Then, the calculation unit 112 calculates the road surface roughness value of the evaluation target road based on the travel information acquired by the information acquisition unit 111, and stores the road surface profile information including the road surface roughness value in the storage unit 120. Then, the determination unit 113 determines whether or not snow has accumulated on the evaluation target road based on the road surface profile information stored in the storage unit 120. The output unit 114 outputs to the destination terminal, together with the road surface profile information stored in the memory unit 120, information including the judgment result of whether or not there is snow, which was judged by the judgment unit 113 based on the road surface profile information (hereinafter referred to as snow accumulation information).

[0033] The output instruction of the road surface profile includes section information capable of identifying the road to be evaluated. The section information includes information indicating the name of the road to be evaluated and the range of the section, for example, "Road: National Highway No. X, Section: Latitude Y to Z". If the road has multiple lanes on one side, such as two lanes on one side, the section information may include information on the lanes to be evaluated, such as "Road: National Highway No. X, Lane: Right End, Section: Latitude Y to Z". Information other than latitude may be used to specify the road to be evaluated. For example, longitude may be used instead of latitude, or longitude may be used in addition to latitude. Furthermore, the distance from the start point of the section may be used. The output instruction of the road surface profile further includes period information specifying the period to be evaluated. The period information includes information indicating the period to be evaluated, for example, "one month from X month Y day". The output instruction of the road surface profile may include information specifying whether or not to output snowfall information, or information instructing the output of only snowfall information.

[0034] An instruction to output the road surface profile may be input to the road surface evaluation device 10 via an operation unit (not shown) that the road surface evaluation device 10 has. The road surface profile information and snow accumulation information are information that can be displayed on a display device such as a display, and a user (e.g., a road management company) can check the road surface profile and the presence or absence of snow accumulation by displaying the road surface profile information, etc. on a display of the user's terminal. The output unit 114 may output the road surface profile information, etc. to the storage unit 120. For example, the road surface profile information, etc. may be output so as to be mapped to map information stored in the storage unit 120.

[0035] Incidentally, wheel slippage on snowy roads is likely to occur when snow accumulated on the road melts or freezes, lowering the coefficient of friction of the road surface (snow surface). Therefore, in order to prevent wheel slippage, it is necessary for users such as road management companies to be notified of the occurrence of snow accumulation before the snow on the road surface melts or freezes. However, since unevenness on the road surface can occur due to depressions and the like in addition to snow accumulation, there are cases where the occurrence of snow accumulation cannot be accurately detected only from the road surface profile information. To address such problems, the determination unit 113 determines the presence or absence of snow accumulation as follows.

[0036] FIG. 9 is a diagram showing an example of road surface profile information generated based on travel information acquired from a plurality of vehicles 20 that traveled on the evaluation target road (latitudes Y to Z of national highway X) during the evaluation target period. The horizontal axis represents the position (latitude) of the vehicle 20 in the traveling direction along the travel lane, and the vertical axis represents the road surface roughness value. Characteristic P11 in the figure represents the road surface profile information of the evaluation target road calculated based on the composite travel information obtained by combining the travel information of the plurality of vehicles 20. Note that, for the sake of simplicity of the drawing, FIG. 9 only shows the road surface profile information of the section SC where snow accumulation has occurred on the evaluation target road.

[0037] As shown in the characteristic P11, the road surface roughness value of the section SC where snow has accumulated has many peaks that are equal to or greater than the predetermined roughness value Th. In this way, in the section where snow has accumulated, the condition of the road surface deteriorates throughout the section. More specifically, many large steps that cause a lateral acceleration of a predetermined amount or more to the vehicle occur throughout the section. Therefore, the determination unit 113 determines whether or not there is a section (hereinafter referred to as a specific section) on the road to be evaluated that has the road surface characteristics (hereinafter referred to as a specific road surface characteristics) as shown in the characteristic P11 on the road to be evaluated, specifically, whether or not there is a section in which the number of times (hereinafter referred to as the number of peaks) in which the road surface roughness value exceeds the predetermined roughness value Th is equal to or greater than a predetermined number, based on the road surface profile information of the road surface to be evaluated. Note that in a section where many peaks appear, the average value of the road surface roughness value increases. Therefore, the determination unit 113 may detect a section where the average value of the road surface roughness value is equal to or greater than a predetermined value as a specific section. Moreover, while snow accumulates over a wide area, road collapses usually occur in spots. Therefore, it is assumed that road surface irregularities due to road depressions will not be detected over a section of a predetermined distance or more. Therefore, the determination unit 113 may detect a section of a predetermined distance or more having specific road surface characteristics as a specific section. When a specific section exists on the road to be evaluated, the determination unit 113 determines that snowfall may have occurred on the road to be evaluated, more specifically, in the specific section on the road to be evaluated.

[0038] Furthermore, in order to be able to more reliably determine whether the unevenness of the road surface indicated by the characteristic P11 is due to snowfall, the determination unit 113 compares the road surface profile information (characteristic P11) based on the driving information acquired during a predetermined period T, which is the evaluation target period, with the road surface profile information for a predetermined period T0 that is earlier than the predetermined period T, to determine whether the unevenness of the road surface is due to snowfall. The predetermined past period T0 is a past period in which no snowfall was detected on the road to be evaluated, such as a period in summer.

[0039] The determination unit 113 determines whether the difference between the road surface profile information based on the travel information acquired in the predetermined period T and the road surface profile information based on the travel information acquired in the past predetermined period T0 is equal to or greater than a predetermined threshold. More specifically, the determination unit 113 first calculates the difference in road surface roughness between corresponding positions based on the road surface profile information based on the travel information acquired in the predetermined period T and the road surface profile information in the past predetermined period T0. At this time, the determination unit 113 may calculate the difference in road surface roughness value for a specific section, instead of calculating the difference in road surface roughness value for the entire road to be evaluated. Note that, when the road surface profile information for the past predetermined period T0 is included in advance in the map information or the like stored in the storage unit 120, the determination unit 113 reads out and acquires the road surface profile information for the past predetermined period T0 from the storage unit 120. When the road surface profile information for the past predetermined period T0 is not stored in the memory unit 120, the determination unit 113 may obtain driving information corresponding to the past predetermined period T0 from the storage device 40 via the communication unit 13, and generate and obtain the road surface profile information for the past predetermined period T0 based on the obtained driving information. Next, when the total value of the calculated absolute values ​​of the differences is equal to or greater than a predetermined value, the determination unit 113 determines that the difference is equal to or greater than a predetermined threshold, and when the total value is less than the predetermined value, the determination unit 113 determines that the difference is less than the predetermined threshold. Note that the method of determining whether the difference is equal to or greater than the predetermined threshold is not limited to this. When the difference is equal to or greater than the predetermined threshold, the determination unit 113 determines that snow has accumulated on the road to be evaluated.

[0040] 10 is a flowchart showing an example of processing executed in the calculation unit 110 (CPU) of the road surface evaluation device 10 according to a predetermined program. The processing shown in this flowchart is repeated at a predetermined cycle while the road surface evaluation device 10 is running. First, in step S11, it is determined whether or not an instruction to output a road surface profile has been input (received).

[0041] If the result in step S11 is negative, the process is terminated. If the result in step S11 is positive, in step S12, road information included in the map information stored in the storage unit 120 is acquired. In step S13, travel information of the vehicle 20 is acquired from the storage unit 40 via the communication unit 13. More specifically, based on the section information and period information included in the output instruction of the road surface profile and the road information acquired in step S12, travel information corresponding to the evaluation target road specified by the section information and corresponding to the evaluation target period specified by the period information is read from the storage unit 120. At this time, if there are multiple vehicles 20 that have traveled on the evaluation target road, travel information corresponding to each of the multiple vehicles 20 is acquired. In addition, when the section information included in the output instruction of the road surface profile includes information on the lane to be evaluated, travel information including position information corresponding to the lane is read from the storage unit 120.

[0042] In step S14, composite travel information is generated based on the travel information read from the storage unit 120 in step S13, and a road surface roughness is estimated based on the composite travel information. More specifically, a road surface roughness value is calculated based on the composite travel information.

[0043] In step S15, information is generated in which the road surface roughness value calculated in step S14 is associated with the road information acquired in step S12, i.e., road surface profile information. In step S16, it is determined whether or not a specific section exists on the road to be evaluated based on the road surface profile information generated in step S15. If the result in step S16 is negative, the process proceeds to step S21. If the result in step S16 is positive, it is determined in step S17 whether or not the length of the specific section is equal to or greater than a predetermined distance. If the result in step S17 is negative, the process proceeds to step S21. If the result in step S17 is positive, in step S18, the road surface profile information for the evaluation period generated in step S15 is compared with road surface profile information for a predetermined period of time prior to the evaluation period. Specifically, the difference between the road surface profile information for the evaluation period and the road surface profile information for the predetermined period of time in the past is calculated. In step S19, it is determined whether or not the difference calculated in step S18 is equal to or greater than a predetermined threshold value. If the result of step S19 is affirmative, then in step S20 it is determined that snow has accumulated on the road to be evaluated, and the process proceeds to step S22. On the other hand, if the result of step S19 is negative, then in step S21 it is determined that snow has not accumulated on the road to be evaluated, and the process proceeds to step S22. In step S22, the road surface profile information generated in step S15 and snow accumulation information including the results of the determinations in steps S20 and S21 are output. This allows the road surface profile information and snow accumulation information to be displayed on a display device such as a display, and the user can check the unevenness of the road surface and the presence or absence of snow accumulation. In order to make it easier for the user to visually recognize the snow accumulation information, the snow accumulation information may be mapped and output on map information including the road to be evaluated as shown in FIG. 5. More specifically, the snow accumulation information may be mapped and output on map information so that the section where it is determined that snow accumulation has occurred is displayed in a predetermined color. In addition, instead of outputting the road surface profile information and the snow accumulation information separately, the snow accumulation information may be included in the road surface profile information and output. For example, the road surface profile information may include snow accumulation information such that the road surface roughness value corresponding to a section determined to have snow accumulation is displayed in a color different from the road surface roughness values ​​corresponding to other sections.

[0044] According to the embodiment of the present invention, the following advantageous effects can be obtained. (1) The road surface evaluation device 10 includes an information acquisition unit 111 that acquires driving information (first driving information) including position information indicating the driving position and acceleration information indicating the acceleration of each of a plurality of vehicles 20 traveling on a road (road to be evaluated); a memory unit 120 that stores first road surface information which is road surface profile information indicating the roughness of the road surface in a first predetermined period; a calculation unit 112 as a generation unit that generates second road surface information which is road surface profile information indicating the roughness of the road surface in a second predetermined period based on the driving information of the plurality of vehicles 20 acquired by the information acquisition unit 111 in a second predetermined period after the first predetermined period; a judgment unit 113 that determines whether the road has specific road surface characteristics based on the second road surface information generated by the calculation unit 112, and if it is determined that the road has specific road surface characteristics, further determines whether snow has accumulated on the road based on the difference between the first road surface information and the second road surface information; and an output unit 114 that outputs snow accumulation information including the judgment result of the judgment unit 113. This allows for an accurate determination of whether snow has accumulated on the road being evaluated, and allows the user to quickly become aware of information about snow accumulation. As a result, it becomes possible to quickly take measures such as removing snow. Furthermore, the above configuration allows the user to instruct measures such as dispatching snowplows to appropriate roads, thereby preventing unnecessary dispatches of snowplows and improving the fuel efficiency of the vehicle. As a result, carbon dioxide emissions are reduced, and climate change can be mitigated.

[0045] (2) The first predetermined period is a period during which no snowfall is detected on the road, making it possible to more accurately determine whether or not a particular road surface condition of the road is caused by accumulated snow.

[0046] (3) The determination unit 113 determines whether or not a specific section having specific road surface properties and a predetermined distance or more exists on the road based on the second road surface information. When the determination unit 113 determines that a specific section exists on the road, the determination unit 113 determines whether or not a difference between the first road surface information and the second road surface information is equal to or greater than a predetermined threshold, and when the difference is equal to or greater than the predetermined threshold, determines that snow has accumulated in the specific section on the road. This makes it possible to more accurately determine whether or not snow has accumulated on the road to be evaluated.

[0047] (4) The specific road surface condition is a road surface condition in which the average roughness of the road surface is equal to or greater than a predetermined value. In a section where snow has accumulated, ruts and snow blocks are generated by vehicle traffic, etc., and the road surface generally deteriorates. Therefore, by using the average roughness of the road surface to determine the presence or absence of snow accumulation, the accuracy of the determination can be improved.

[0048] (5) A specific road surface condition is a road surface condition in which the number of times (peak count) that the roughness of the road surface exceeds a predetermined value is equal to or greater than a predetermined number. In a section where snow has accumulated, ruts and snow blocks are generated by vehicle traffic, and many relatively large steps occur. Therefore, by using the peak count to determine the presence or absence of snow accumulation, the accuracy of the determination can be improved.

[0049] The above embodiment can be modified in various ways. The following describes modified examples. In the above embodiment, when the determination unit 113 as a road surface determination unit determines that the road to be evaluated has a specific road surface property, the determination unit 113 as a snow accumulation determination unit determines whether snow accumulation has occurred on the road to be evaluated based on the difference between the first road surface information and the second road surface information. However, the determination unit 113 may detect an intersection included in the road to be evaluated based on the map information stored in the storage unit 120 as an intersection detection unit. Then, when the intersection is detected, the determination unit 113 may determine whether snow accumulation has occurred on the road to be evaluated based on the difference between the first road surface information and the second road surface information corresponding to the position of the intersection, that is, based on the change in the roughness of the road surface at the intersection. At an intersection, not only straight-moving vehicles but also right- and left-turning vehicles are present, so that when snow accumulates, snow blocks and ruts with complex shapes and directions are likely to occur due to these vehicles. Therefore, by determining the presence or absence of snow accumulation based on the change in the roughness of the road surface at the intersection as described above, the accuracy of the determination can be further improved.

[0050] In the above embodiment, the information acquisition unit 111 as a travel information acquisition unit acquires travel information of each of the multiple vehicles 20 traveling on the road to be evaluated, and the calculation unit 112 as a generation unit generates road surface profile information (second road surface information) indicating the roughness of the road surface in the second predetermined period based on the travel information of the multiple vehicles 20 acquired by the information acquisition unit 111 in a second predetermined period after the first predetermined period. However, the travel information acquisition unit may further acquire travel information (second travel information) of each of the multiple vehicles 20 traveling in a predetermined section up to the road to be evaluated. Then, the generation unit may generate third road surface information, which is road surface profile information indicating the roughness of the road surface in the predetermined section in the second predetermined period, based on the second travel information. At this time, the determination unit 113 further determines whether snow has accumulated on the road based on the roughness of the road surface in the predetermined section based on the third road surface information. More specifically, the determination unit 113 determines that snow has accumulated on the road when the difference between the first road surface information and the second road surface information is equal to or greater than a predetermined threshold (first predetermined threshold) and the roughness of the road surface in the predetermined section based on the third road surface information is equal to or greater than a predetermined threshold (second predetermined threshold). In the section leading to the road to be evaluated, particularly in the parking lot of a store which is the starting point of travel, there are a plurality of vehicles with different travel directions and travel positions, such as an entering vehicle traveling while searching for a parking space and an exiting vehicle traveling while searching for an exit. In addition, the travel positions of these vehicles may change depending on the availability of the parking lot, etc. Therefore, when snow accumulates, snow blocks and ruts with complex shapes and directions are likely to occur. Therefore, by determining the presence or absence of snow based on the roughness of the road surface in the section leading to the road as described above, the accuracy of the determination can be further improved. As described above, since the driving positions of each vehicle are different in the parking lot, the judgment unit 113 judges whether or not snow has accumulated based on the total value of the roughness value (absolute value) of the road surface in the specified section calculated based on the third road surface information, without comparing the third road surface information with past road surface information.

[0051] Also, in the above embodiment, the storage device 40 stores the travel information of the multiple vehicles 20, and the information acquisition unit 111 as a travel information acquisition unit acquires the travel information of the multiple vehicles 20 corresponding to the evaluation target period and the evaluation target road from the storage device 40 via the communication unit 13. However, the travel information of the multiple vehicles 20 may be stored in the storage unit 120 of the road surface evaluation device 10. In that case, the information acquisition unit 111 reads out and acquires the travel information of the multiple vehicles 20 corresponding to the evaluation target period and the evaluation target road from the storage unit 120.

[0052] Furthermore, in the above embodiment, the information acquisition unit 111 as a map information acquisition unit acquires map information including information on roads on which the vehicle 20 travels from the storage unit 120. However, the map information acquisition unit may acquire map information including information on roads on which the vehicle 20 travels from an external server device or the like.

[0053] The above description is merely an example, and the present invention is not limited to the above-mentioned embodiment and modifications, as long as the features of the present invention are not impaired. One or more of the above-mentioned embodiment and modifications can be arbitrarily combined, and modifications can also be combined with each other. [Explanation of symbols]

[0054] 10 Road surface evaluation device, 20, 20-1 to 20-n Vehicle, 30 Vehicle-mounted terminal, 40 Travel information storage device, 110 Calculation unit, 111 Information acquisition unit, 112 Calculation unit, 113 Determination unit, 114 Output unit, 120 Storage unit

Claims

1. a travel information acquisition unit that acquires travel information including position information indicating a travel position and acceleration information indicating an acceleration of each of a plurality of vehicles traveling on a road; a storage unit configured to store first road surface information indicating a roughness of a road surface of the road during a first predetermined period; a generating unit that generates second road surface information indicating roughness of the road surface during a second predetermined period after the first predetermined period based on the travel information of the plurality of vehicles acquired by the travel information acquiring unit during the second predetermined period; a road surface determination unit that determines whether the road has a specific road surface property based on the second road surface information generated by the generation unit; a snow accumulation determination unit that, when the road surface determination unit determines that the road has the specific road surface property, determines whether or not snow has accumulated on the road based on a difference between the first road surface information and the second road surface information; and and an output unit that outputs snow accumulation information including a result of the determination by the snow accumulation determination unit.

2. The road surface evaluation device according to claim 1, A road surface evaluation device, characterized in that the first predetermined period is a period during which no snowfall is detected on the road.

3. The road surface evaluation device according to claim 1, the road surface determination unit determines whether or not a specific section having the specific road surface property and having a predetermined distance or more exists on the road based on the second road surface information; The snow accumulation determination unit, when the road surface determination unit determines that the specific section exists on the road, determines whether the difference between the first road surface information and the second road surface information is greater than or equal to a predetermined threshold, and when the difference is greater than or equal to the predetermined threshold, determines that snow accumulation has occurred in the specific section on the road.

4. 3. The road surface evaluation device according to claim 2, A road surface evaluation device, characterized in that the specific road surface condition is a road surface condition in which an average value of roughness of the road surface is equal to or greater than a predetermined value.

5. 3. The road surface evaluation device according to claim 2, The determination unit is The road surface evaluation device is characterized in that the specific road surface condition is a road surface condition in which the number of times that the roughness of the road surface exceeds a predetermined value is equal to or greater than a predetermined number.

6. The road surface evaluation device according to claim 1, An intersection detection unit detects an intersection included in the road, the first road surface information and the second road surface information are information in which information indicating a position on the road is associated with a roughness value indicating the roughness of the road surface at the position, The road surface evaluation device is characterized in that, when an intersection is detected by the intersection detection unit, the judgment unit determines whether or not snow has accumulated on the road based on the difference between the first road surface information and the second road surface information corresponding to the position of the intersection.

7. 4. The road surface evaluation device according to claim 3, The travel information is first travel information, The travel information acquisition unit further acquires second travel information including the position information and the acceleration information of each of the plurality of vehicles traveling in a predetermined section up to the road, the generating unit generates third road surface information indicating a roughness of the road surface in the specified section during the second specified period based on the second traveling information, The road surface evaluation device is characterized in that the judgment unit further judges whether or not snow has accumulated on the road based on the roughness of the road surface in the specified section based on the third road surface information.

8. The road surface evaluation device according to claim 7, the predetermined threshold is a first predetermined threshold, A road surface evaluation device characterized by determining that snow accumulation has occurred on the road when the difference between the first road surface information and the second road surface information is greater than or equal to the first predetermined threshold and the roughness of the road surface in the specified section based on the third road surface information is greater than or equal to a second predetermined threshold.

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