JP7653683B2 - curb - Google Patents

Description

The present invention relates to curbs that are installed along paths on which vehicles, etc. travel.

Systems for ensuring road traffic safety using radar systems such as millimeter waves have been developed. For example, Patent Document 1 discloses a radar system that measures the distance between vehicles and the relative speed between vehicles by providing a corner reflector on the rear of a vehicle to reflect radar waves irradiated from a rear vehicle in the direction of incidence.
In addition, if a reflector is provided on a road structure, etc., it is possible to appropriately grasp the position of a vehicle traveling on a road relative to the roadway by irradiating the reflector with a radar wave and detecting the reflected wave. If the position of a vehicle relative to the roadway can be grasped, the safety of an automatic driving system, etc. during driving will be improved.
Furthermore, if radar systems become widespread, it will be possible to share data and grasp traffic volume, which can be used to ensure safe driving.

It is known that the propagation of radar waves is attenuated depending on the rainfall intensity and the size of the raindrops. For example, Patent Document 2 discloses a rainfall observation device that calculates the rainfall intensity in a propagation path from the deviation in the level of a signal arriving through the propagation path and the length of the propagation path. Therefore, the amount of rainfall can be estimated from the attenuation of the reflection intensity of a radar wave irradiated on a reflector installed on a road structure or the like. By observing the amount of rainfall using a radar system, highly accurate rainfall data can be obtained, and damage caused by heavy rain disasters can be reduced.
However, providing new structures on roads specifically for radar systems, or attaching components such as corner reflectors to existing road structures, may cause obstruction to traffic.

JP 2000-103283 A JP 2004-354080 A

The objective of this invention is to propose a curb that can increase the reflection strength of radar waves irradiated onto road facilities, etc., without constructing a new dedicated structure used only for reflecting radar waves or installing a protruding reflector on an existing structure.

The curbstone of the present invention, which solves the above-mentioned problems, is installed in a row along the roadway, and a corner cube-shaped reflection enhancing portion for increasing the reflection strength of radar waves is formed in a rectangular recess that opens facing the roadway.
Such a curbstone can be used in safe driving systems and rainfall measurement systems that use radar waves, because the reflection strength of the corner cube-shaped reflection enhancing parts with right angles is increased. Because the reflection enhancing parts are formed directly on the curbstone itself, there is no need to install a new structure dedicated to the sole purpose of reflecting radar waves, or to install a reflector protruding from an existing structure, and therefore there is no impact on vehicle traffic.
In addition, by utilizing the curbstone, the amount of rainfall can be estimated based on the attenuation of the reflection intensity of the radar wave incident on the reflection enhancing portion. According to this rainfall amount estimation method, the amount of rainfall can be estimated using the curbstone installed on the road, so that it is possible to appropriately grasp the rainfall conditions at the curbstone installation location, and by utilizing this, damage caused by rainfall can be minimized.
The reflection-enhancing portion is formed in a rectangular recess that opens toward the roadway, and since the reflection - enhancing portion is formed in a shape similar to that of a three-sided corner reflector, high reflection strength can be ensured.
If the reflection enhancing portion is a reflector embedded in a hole formed by drilling a side surface facing the roadway, a higher reflection intensity can be ensured.

The curbstone of the present invention makes it possible to increase the reflection strength of radar waves irradiated onto road facilities without constructing new structures dedicated solely to reflecting radar waves or protruding reflectors from existing structures, making it possible to utilize road facilities in traffic safety systems.

FIG. 2 is a perspective view of a curb according to the present embodiment. FIG. 13 is a perspective view showing an example of a curb installation situation. FIG. 11 is a perspective view of a curb according to another embodiment. FIG. 11 is a perspective view of a curb according to another embodiment. FIG. 13 is a plan view showing an outline of the positional relationship between a curb and a radar device in a simulation. FIG. 13 is a schematic diagram showing the relationship between road width and device height in a simulation.

In this embodiment, a curbstone 1 installed along a roadway for vehicles or the like will be described. Fig. 1 shows the curbstone 1 of this embodiment. As shown in Fig. 1, the curbstone 1 of this embodiment is a concrete block member, and is made of a columnar member having a length L = 60 cm, a height H = 15 cm, and a base width B = 15 cm. A reflection enhancing portion 3 is formed on a side surface 2 of the curbstone 1 facing the roadway, in order to enhance the reflection strength of radar waves.
The reflection enhancing portion 3 is formed in a recess 4 that is rectangular in front view and opens toward the travel path. In this embodiment, three recesses 4, 4, 4 are formed at intervals in the longitudinal direction of the curb 1. The recess 4 is formed in a cube shape with a depth d, height h, and width w of 5 cm. That is, the corners between the bottom surface and the four side walls of the recess 4 are right angles, and the corners between the side walls are also right angles. As a result, a corner cube-shaped reflection enhancing portion 3 with three faces that meet at right angles is formed at each of the four corners of the bottom surface of the recess 4. The reflection enhancing portion 3 repeats reflection within the three faces and accurately bounces back the radar wave in the incident direction, even if the radar wave is incident on any of the three faces. Therefore, the reflection enhancing portion 3 can obtain a high reflection strength similar to that of a three-sided corner reflector.
The recess 4 may be formed by providing a protrusion (box cutout) on a formwork when manufacturing the curbstone 1, or by carving into the side of the curbstone 1 which is formed in a rectangular column shape.

Fig. 2 shows an example of the installation state of the curbstones 1. As shown in Fig. 2, the curbstones 1 are installed in a row along the roadway 5, so that a vehicle C equipped with a driving safety system can properly grasp the position of the vehicle C relative to the roadway 5 by detecting the reflected wave of the radar wave R irradiated to the reflection enhancing portion 3 of the curbstone 1 while traveling on the roadway 5, thereby ensuring safe travel.
The curb 1 can also be used to observe the amount of rainfall. That is, the amount of rainfall can be estimated from the attenuation of the reflection intensity of radar waves R that are emitted from a permanent radar device or the like (not shown) installed along the road and enter the reflection enhancing portion 3 of the curb 1. Therefore, if the curb 1 is installed in a row along the road 5, a large amount of high-resolution rainfall data can be obtained, which can be used to reduce damage caused by heavy rain disasters.

According to the curb 1 of this embodiment, the reflection strength of the radar wave R is increased by the corner cube-shaped reflection enhancing portion 3 having right angles, so it can be used in a safe driving system or a rainfall measurement system that uses the radar wave R. Since the reflection enhancing portion 3 is formed directly on the curb 1 itself, there is no need to install a dedicated structure used only for reflecting the radar wave R or to install a reflector protruding from an existing structure. Therefore, there is no impact on the passage of the vehicle C.
In addition, since the amount of rainfall can be estimated using the curbstone 1 installed on the road, it is possible to properly grasp the rainfall conditions at the location where the curbstone 1 is installed, and by utilizing this, damage caused by rainfall can be minimized. Moreover, since the outer shape of the curbstone 1 of this embodiment is not significantly different from that of an existing curbstone, the curbstone 1 can be installed in place of the existing curbstone. In other words, if the curbstone 1 is installed in place of the existing curbstone, a large number of curbs 1 can be distributed and installed in the area where it is desired to grasp the rainfall conditions without having to secure new installation space.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and each of the above-described components can be appropriately modified without departing from the spirit of the present invention.
For example, there is no limitation on the number and arrangement of the reflection enhancing portions 3 formed on the curb 1. For example, they may be formed at only one location in the center of the curb 1, or at both ends of the curb 1.
3, the reflection enhancing portion 3 may be formed by cutting out the end of the curbstone 1. That is, the reflection enhancing portion 3 may be formed at the bottom of a cut 8 (recess 4) formed at the corner between the side surfaces of the end of the curbstone 1. In this case, the cuts 8 of adjacent curbs 1 are combined to form a recess 4 that is rectangular when viewed from the front.
In the above embodiment, the reflection enhancing portion 3 is formed by forming a cubic recess 4 in the curb 1, but the reflection enhancing portion 3 may be a reflector 7 embedded in a hole 6 formed by drilling a side surface 2 of the curb 1 facing the running path 5, as shown in Fig. 4. The recess 4 is not limited to a cubic shape, and may be, for example, a rectangular parallelepiped shape or a triangular pyramid shape.
In addition, in the above embodiment, a case was described in which the reflection-enhancing portion 3 is formed by a recess 4 formed on the side surface 2 of the curb 1, but the reflection-enhancing portion 3 may also be formed by forming a protrusion on the side surface 2.

The following shows the results of a simulation in which the reflection intensity of the reflection enhancing portion 3 of the curb 1 was confirmed.
(1) Reflection Intensity When the Shape of the Recess is Changed In the simulation, the ratio (ratio of the number of reflected rays) of the reflection intensity of the reflection enhancing portion 3 to the reflection intensity of a curbstone (comparative example) without the reflection enhancing portion 3 (recess 4) was calculated. Figure 5 shows an overview of the calculation conditions in the simulation.
As shown in Figure 5, in both the example and the comparative example, 10 curbs were placed side by side in an area of 5.8 m, and radar waves R were irradiated onto the curbs from the opposite side of a 10 m wide road to calculate the reflection intensity. The radar waves R irradiated onto the curbs were a millimeter wave radar, and were irradiated from a radar device installed at a height of 5 m.
In this simulation, as an example, the ratio of the number of reflection rays was calculated for each of the cases where one reflection reinforcing section 3 (recess 4) was formed on the curb 1, two reflection reinforcing sections 3 (recess 4) were formed, and three reflection reinforcing sections 3 (recess 4) were formed. The reflection intensity was also calculated for each of the cases where the depth d, height h, and width w of the recess 4 were changed to 2.5 cm, 5 cm, and 10 cm, respectively. Table 1 shows the calculation results for the case where there is one reflection reinforcing section 3, Table 2 shows the calculation results for the case where there are two reflection reinforcing sections 3, and Table 3 shows the calculation results for the case where there are three reflection reinforcing sections 3.

As shown in Tables 1 to 3, it was confirmed that by forming a recess 4 (reflection enhancing portion 3) in the curb 1, the ratio of the number of reflected rays becomes larger and the reflection intensity increases compared to a curb that does not have a reflection enhancing portion 3.
Furthermore, when comparing the difference in the reflected ray number ratio due to the difference in the number of recesses 4 for the "basic shape" in which the depth d, height h and width w of the recesses 4 are all 5 cm, the reflected ray number ratio was 7.89 when there was one recess 4, whereas it was 14.01 when there were two recesses 4 and 20.38 when there were three recesses 4. Therefore, it was confirmed that the reflection intensity was increased by increasing the number of recesses 4 (reflection-enhancing portions 3).
In addition, when any one of the depth d, height h and width w of the recess 4 was 2.5 cm and the others were 5 cm, the ratio of the number of reflected rays was lower than that of the basic shape in which the depth d, height h and width w of the recess 4 were all 5 cm.
Furthermore, while the reflection intensity decreased when the depth of the recess 4 was increased to 10 cm, even when the width or height was increased to 10 cm, there was no significant change from the basic shape (all 5 cm).
From the results shown in Tables 1 to 3, it was confirmed that in this simulation, if the depth of the recess 4 is 5 cm or less, the ratio of the number of reflected rays becomes more than twice as high, and the reflection intensity increases significantly, compared to the curbstone 1 that does not have the reflection enhancing section 3. It was also confirmed that if the entrance (width and height) of the recess 4 is 5 cm or more, the ratio of the number of reflected rays becomes more than twice as high, and the reflection intensity increases significantly, compared to the curbstone 1 that does not have the reflection enhancing section 3.

(2) Reflection Intensity When Road Width and Device Height Are Changed Next, we calculated the reflection intensity when changing the height position (device height) of the radar device that irradiates the curb 1 with the millimeter wave radar and the road width. Figure 6 shows the positional relationship between the road width and the device height in this simulation.
In this simulation, the height of the radar device was changed to 1.25 m, 2.5 m, and 5 m. Also, calculations were performed for cases where the road width was changed to 5 m, 10 m, and 20 m.
Table 4 shows the simulation results when the road width is 5m and the device height is 1.25m, Table 5 shows the simulation results when the road width is 5m and the device height is 2.5m, and Table 6 shows the simulation results when the road width is 5m and the device height is 5m.
Table 7 shows the simulation results when the road width is 10 m and the device height is 1.25 m, Table 8 shows the simulation results when the road width is 10 m and the device height is 2.5 m, and Table 9 shows the simulation results when the road width is 10 m and the device height is 5 m.
Table 10 shows the simulation results when the road width is 20 m and the device height is 1.25 m, Table 11 shows the simulation results when the road width is 20 m and the device height is 2.5 m, and Table 12 shows the simulation results when the road width is 20 m and the device height is 5 m.

As shown in Tables 4 to 12, it was confirmed that the curbstone 1 of this embodiment increases the reflection intensity regardless of the road width and the height of the radar device. In particular, when the depth d of the recess 4 is 5 cm, the height h is 5 cm, and the width w is 10 cm, the reflection intensity is more than doubled in all cases. Also, when the depth d of the recess 4 is 5 cm, the height h is 5 cm, and the width w is 5 cm, the reflection intensity is more than doubled in all cases except when the road width is 5 m and the device height is 5 m.

REFERENCE SIGNS LIST 1 Curb 2 Side 3 Reflection enhancing portion 4 Recess 5 Road 6 Hole 7 Reflector 8 Notch C Vehicle R Radar wave

Claims (2)

A curb stone is provided on the side of the roadway in a direction of travel,
A curb characterized in that a corner cube-shaped reflection enhancing portion for enhancing the reflection strength of radar waves is formed in a rectangular parallelepiped recess that opens toward a travel path. 2. The curbstone according to claim 1 , wherein the recess is a hole formed by drilling a side surface facing the roadway.

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