JP2021039632A - Vehicle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle detector capable of effectively using a reflected wave when a vehicle is not detected. SOLUTION: A vehicle detector 1 is installed above a road R, and has an ultrasonic head portion 10 that transmits ultrasonic waves toward a road surface R of a facing road and receives reflected waves of ultrasonic waves, and ultrasonic waves. Information based on the distance from the head unit 10 to the road surface R is set, the reflection arrival time is acquired, and the vehicle sensing unit 21 that detects the vehicle V traveling on the road surface R based on the acquired reflection arrival time is provided. ing. Then, the vehicle sensing unit 21 determines that the vehicle V has been detected when the reflection arrival time is less than the threshold value th1, and the road surface state of the road surface R when the reflection arrival time is equal to or more than the threshold value th1 and less than the threshold value th2. It is determined that a change in is detected. [Selection diagram] Fig. 2

Description

The present invention relates to a vehicle detector that detects a traveling vehicle on a road.

Conventionally, a vehicle detector that detects the presence or absence of a vehicle using ultrasonic waves has been known in order to check the traffic volume on the road. In such a vehicle detector, for example, a head for transmitting and receiving ultrasonic waves is attached so as to face the road surface from the sky above the road, ultrasonic waves are transmitted from the head toward the road surface in a substantially vertical direction, and the reflected wave is received. The vehicle is detected based on the time until the vehicle is used (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2002-251695

The purpose of the vehicle detector of Patent Document 1 is to detect a vehicle, but on the other hand, when the vehicle is not detected, the reflected wave reflected on the road surface or the like is detected. However, at present, the reflected wave reflected on the road surface or the like is not particularly utilized. That is, at present, it cannot be said that the received reflected wave is effectively utilized during the period when the vehicle is detected, but is not effectively utilized during the period when the vehicle is not detected.

Therefore, an object of the present invention is to provide a vehicle detector capable of effectively utilizing reflected waves when the vehicle is not detected.

The invention made to solve the above problems includes an ultrasonic head unit that is installed over a road, transmits ultrasonic waves toward the facing road, and receives reflected waves of the ultrasonic waves, and the ultrasonic waves. An acquisition unit that acquires information on the time from when the head unit transmits the ultrasonic waves until the reflected wave is received, and a vehicle traveling on the road based on the information on the time acquired by the acquisition unit. A sensing unit for sensing is provided, and the sensing unit is set with distance information from the ultrasonic head unit to the road, and the information regarding the time is used as a reference for determining that the vehicle has been detected. If it is less than the first threshold value, which is a value related to, it is determined that the vehicle has been detected, and the information related to the time is equal to or more than the first threshold value, and the ultrasonic head portion calculated based on the distance information has. The vehicle detector is characterized in that if it is less than the time to receive the reflected wave reflected on the road after transmitting the ultrasonic wave, it is determined that a change in the road surface condition of the road has been detected.

Further, the sensing unit has a value equal to or more than the first threshold value and less than the time required for the ultrasonic head unit calculated based on the distance information to receive the reflected wave reflected on the road after transmitting the ultrasonic wave. When the second threshold value is set and the information regarding the time is equal to or greater than the first threshold value and less than the second threshold value, it is determined that a change in the road surface condition of the road has been detected. Can be a feature.

Further, a temperature detecting unit for detecting the ambient temperature of the ultrasonic head unit is further provided, and the sensing unit corrects the first threshold value and the second threshold value based on the ambient temperature detected by the temperature detecting unit. , Can be characterized.

Further, the sensing unit may output warning information when it is determined that the change in the road surface condition of the road has been detected.

In addition, an ultrasonic head unit that is installed above the road and transmits ultrasonic waves toward the road facing the road and receives the reflected waves of the ultrasonic waves, and the ultrasonic head unit transmit the ultrasonic waves. An acquisition unit that acquires information on the distance to the object that reflected the ultrasonic waves based on the time from to receiving the reflected wave, and on the road based on the information on the distance acquired by the acquisition unit. A sensing unit for detecting a traveling vehicle is provided, and the sensing unit is for determining that distance information from the ultrasonic head unit to the road is set and the information regarding the distance has detected the vehicle. When it is less than the first threshold value which is a value related to the reference distance, it is determined that the vehicle has been detected, and when the information related to the distance is equal to or more than the first threshold value and less than the distance based on the distance information. Can be a vehicle detector characterized in that it is determined that a change in the road surface condition of the road has been detected.

According to the present invention, changes in road surface conditions such as flooding and snow cover can be detected. Therefore, the reflected wave when the vehicle is not detected can be effectively used.

It is a figure which shows the installation example of the vehicle detector which concerns on 1st Embodiment of this invention. It is a functional block diagram of the controller shown in FIG. It is explanatory drawing when the vehicle is not detected. It is explanatory drawing when the vehicle is detected. It is explanatory drawing which showed that the threshold value fluctuates with temperature. It is explanatory drawing when the submergence is detected. It is a flowchart of the operation of the detection of a vehicle and the detection of flooding, etc. by the vehicle detector shown in FIG. It is a schematic block diagram of the alarm system which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram of the alarm system which concerns on other embodiment of this invention.

FIG. 1 is a diagram showing an installation example of the vehicle detector 1 according to the present embodiment. As shown in this figure, the vehicle detector 1 is attached to a controller 20 attached to a pole 151 erected on the side of the road surface R of the road on which the vehicle travels, and an arm 152 extending from the pole 151 to the sky above the road. It is composed of the ultrasonic head portion 10 and the ultrasonic head portion 10.

As is well known, the ultrasonic head unit 10 has a transmitter that transmits ultrasonic waves of a predetermined frequency toward the road surface R, and a receiver that receives the reflected wave of the ultrasonic waves and converts them into an electric signal. I have.

As shown in FIG. 2, the controller 20 includes a vehicle sensing unit 21, a communication processing unit 22, and a temperature sensor 23.

The vehicle sensing unit 21 outputs a transmission signal transmitted as ultrasonic waves from the transmitter of the ultrasonic head unit 10 at regular intervals. Further, the vehicle sensing unit 21 receives an electric signal indicating the reflected wave received by the receiver of the ultrasonic head unit 10, and determines the time from the output of the transmission signal to the reception of the electric signal of the reflected wave (reflection arrival time). Time. That is, the vehicle sensing unit 21 functions as an acquisition unit that acquires information regarding the time from when the ultrasonic head unit 10 transmits ultrasonic waves to when the reflected wave is received.

Further, the vehicle detection unit 21 detects the vehicle based on the measured reflection arrival time and a predetermined threshold value for vehicle detection (first threshold value), and outputs vehicle detection information. Further, when the vehicle is not detected, the vehicle sensing unit 21 detects the change in the road surface condition of the road based on the time measured and the predetermined threshold value (second threshold value) for detecting the change in the road surface condition, and the vehicle surface condition is detected. When a change in is detected, an alarm (alarm information) is output.

Here, the road surface condition in the present embodiment means a condition in which the running of the vehicle V is affected by deposits on the road surface R such as flooding, snow cover, and earth and sand.

Further, the vehicle sensing unit 21 is set with distance information from the road surface R to the ultrasonic head unit 10, that is, the height H0 of the ultrasonic head unit 10 (see FIG. 3).

The communication processing unit 22 transmits the vehicle detection information detected by the vehicle detection unit 21 to the truck server 30. The vehicle detection information is not limited to the information indicating that the vehicle has been detected, and may include the number of detected vehicles (number of passages, number of counts) within a predetermined time, the duration of detection, and the like.

The temperature sensor 23 detects the air temperature in the vicinity of the installation position of the vehicle detector 1 on the road surface R. The temperature sensor 23 may be installed in or near the ultrasonic head portion 10 instead of the controller 20. That is, it suffices if the air temperature in the atmosphere transmitted by the ultrasonic waves transmitted by the ultrasonic head unit 10 can be detected or estimated. That is, the temperature sensor 23 functions as a temperature detection unit that detects the ambient temperature of the ultrasonic head unit 10.

The tracan server 30 is a server device installed in, for example, a road administrator's office. The tracan server 30 collects vehicle detection information transmitted from the controller 20. The collected information is used for traffic volume surveys and traffic light control.

The automatic notification device 40 is, for example, a notification device installed on the side of a road or the like to notify the flooding of a road or the like. The automatic notification device 40 reports flooding or the like based on an alarm transmitted from the controller 20.

Next, the operation of the controller 20 having the above-described configuration will be described with reference to FIGS. 3 to 6. FIG. 3 is a diagram showing the relationship between the ultrasonic head unit 10 and the road surface R when the upper stage does not detect the vehicle, that is, the lower stage shows the waveform of the ultrasonic wave transmitted from the ultrasonic head unit 10 and the road R. It is a figure which showed the example of the waveform of the reflected wave reflected on the road surface of.

As shown in the upper part of FIG. 3, the ultrasonic wave transmitted from the ultrasonic head unit 10 is reflected by the road surface R, and the reflected wave is received by the ultrasonic head unit 10. At this time, as shown in the lower part of FIG. 3, the signal waveform transmitted from the ultrasonic head unit 10 is received as a reflected waveform reflected by the road surface R. Here, the reflection arrival time in the case of FIG. 3 is set to t0. That is, t0 is the reflection arrival time when reflected by the road surface R. In the lower part of FIG. 3, the difference between the transmitted waveform and the reflected wave waveform is due to consideration of attenuation and the like.

Next, the case where the vehicle V is detected is shown in FIG. FIG. 4 is a diagram showing the case where the vehicle V is detected in the upper row, and a diagram showing an example of the waveform of the ultrasonic wave transmitted from the ultrasonic head unit 10 and the waveform of the reflected wave reflected by the vehicle V in the lower row.

As shown in the upper part of FIG. 4, the ultrasonic wave transmitted from the ultrasonic head unit 10 is reflected by the vehicle V, and the reflected wave is received by the ultrasonic head unit 10. At this time, as shown in the lower part of FIG. 4, the signal waveform transmitted from the ultrasonic head unit 10 is received as a reflected waveform reflected by the vehicle V. Here, the reflection arrival time in the case of FIG. 4 is t1. That is, t1 is the reflection arrival time when reflected by the vehicle V. Since the reflection surface of the vehicle V is located at a position higher than the road surface R (a position close to the ultrasonic head portion 10), the distance through which the ultrasonic waves propagate is shortened, and the reflection arrival time t1 is shorter than the reflection arrival time t0.

In the present embodiment, the threshold value th1 is set for the reflection arrival time in order to detect the vehicle V. This threshold value th1 is set to the time when the vehicle V is reflected at a height at which it can be sensed. An example of the threshold value th1 can be the time when the reflection is performed at a height of 50 cm from the road surface R.

It is also known that the speed of sound changes with temperature. Therefore, in the present embodiment, the threshold value th1 is corrected by the air temperature detected by the temperature sensor 23 (see FIG. 5). It is known that the speed of sound C is calculated by the following equation (1), where te is the temperature (air temperature).
C = 331.5 + 0.6te [m / s] ... (1)

For example, when the air temperature is 15 ° C. and 30 ° C., the speed of sound is 340.5 m / s and 349.5 m / s, respectively, according to the equation (1). Further, it is known that the distance H from the ultrasonic head portion 10 to the reflection surface is calculated by the following equation (2), where t is the reflection arrival time.
H = (C × t) / 2 [m] ... (2)

For example, when the ultrasonic head portion 10 is installed at a height of 5 m (H0 = 5 m) from the road surface R, the vehicle detection is performed at a height of 50 cm (0.5 m) from the road surface R. At this time, according to the equation (2), the threshold value th1 when the air temperature is 15 ° C. is about 26.4 ms, and the threshold value th1 when the air temperature is 30 ° C. is about 25.8 ms.

This temperature correction may be performed by setting a calculation formula or the like in the vehicle sensing unit 21 in advance, or a table showing the relationship between the height of the ultrasonic head unit 10, the height to be detected by the vehicle, the air temperature, and the threshold value th1. It may be set in advance in the vehicle sensing unit 21.

Next, the detection of changes in the road surface condition such as flooding and snow cover will be described with reference to FIG. FIG. 6 shows an example of a case where the road surface (road) R is submerged in the upper row, and an example of the waveform of the ultrasonic wave transmitted from the ultrasonic head portion 10 and the waveform of the reflected wave reflected on the submerged surface in the lower row. It is a figure.

As shown in the upper part of FIG. 6, the ultrasonic wave transmitted from the ultrasonic head unit 10 is reflected by the submerged surface W, and the reflected wave is received by the ultrasonic head unit 10. In FIG. 6, since the water is flooded, the flooded surface W is higher than the road surface R. Therefore, the height H1 from the submerged surface W to the ultrasonic head portion 10 is smaller than H0, which is the height from the road surface R to the ultrasonic head portion 10. In the state as shown in the upper part of FIG. 6, as shown in the lower part of FIG. 6, the signal waveform transmitted from the ultrasonic head unit 10 is received as a reflected waveform. Here, since the submerged surface W is located higher than the road surface R, the distance through which the ultrasonic waves propagate is shortened, and the reflection arrival time is shorter than the time t0 shown in FIG.

Therefore, in the present embodiment, for the reflection arrival time, in addition to the threshold value th1, a value larger than the threshold value th1 is set, that is, the threshold value th2, which is the time when the vehicle V is reflected at a height lower than the height at which the vehicle V can be perceived. ..

It is preferable that the threshold value th2 is set to a time corresponding to a certain height at which it is necessary to issue an alarm (alarm) because there is an obstacle in traveling on the road due to flooding, snow cover, or the like. For example, if the threshold value th1 is the time corresponding to the position 50 cm from the road surface R, the threshold value th2 can be the time corresponding to the position about 20 cm from the road surface R. The threshold value th2 is also corrected by the temperature (air temperature). Since this threshold value th2 detects flooding, snow cover, etc. as described above, it is needless to say that the threshold value th2 is set to a time corresponding to a position higher than the road surface R.

When the vehicle V is detected, a value less than the threshold value th1 is usually detected directly. On the other hand, in flooding and snow cover, the water surface and the like gradually rise, so that the reflection arrival time is detected once at a value equal to or higher than the threshold value th1. Therefore, when a value having a reflection arrival time of the threshold value th1 or more is detected, it is possible to determine whether or not the reflection is submerged by comparing with the threshold value th2.

Next, the operation of detecting the vehicle V and detecting flooding in the vehicle detector 1 described above will be described with reference to the flowchart of FIG. 7. The flowchart shown in FIG. 7 mainly operates in the vehicle sensing unit 21.

First, the height H0 of the ultrasonic head unit 10 is set in the vehicle sensing unit 21 (step S11). Next, the reflection arrival time is measured (step S12). That is, the time until the vehicle sensing unit 21 outputs the transmission signal and receives the electric signal of the reflected wave is clocked.

Next, the threshold value th1 and the threshold value th2 are corrected based on the air temperature detected by the temperature sensor 23 (step S13). It should be noted that step S13 may be appropriately performed according to the detected air temperature, not after step S12. That is, the vehicle sensing unit 21 corrects the threshold value th1 (first threshold value) and the threshold value th2 (second threshold value) based on the air temperature (ambient temperature) detected by the temperature sensor 23 (temperature detection unit).

Next, it is determined whether or not the reflection arrival time measured in step S12 is less than the threshold value th1 (step S14). If it is less than the threshold value th1 (step S14: Yes), the vehicle detection information is output as vehicle detection (step S15). When the number of detected vehicles and the duration of detection within a predetermined time are included in the vehicle detection information, the number of detections is counted up for each determination in step S14. That is, the vehicle sensing unit 21 detects the vehicle when the reflection arrival time (information about the time) is less than the threshold value th1 (the first threshold value which is a value related to the reference time for determining that the vehicle has been detected). It is judged that it has been done.

Next, it is determined whether or not the sensing operation is completed (step S16), if it is not completed (step S16: No), the process returns to step S12, and if it is completed (step S16: Yes), the flowchart is terminated.

On the other hand, as a result of the determination in step S14, if the threshold value is th1 or more (step S14: No), it is determined whether or not the threshold value is less than th2 (step S17). If it is less than the threshold value th2 (step S17: Yes), an alarm is output as detection of a change in the road surface condition such as flooding (step S18). If the threshold value is th2 or more (step S17: No), the process proceeds to step S16 without doing anything, assuming that the change is not such that the road surface condition is detected or an alarm is output. That is, in the vehicle sensing unit 21, the reflection arrival time (information about time) is equal to or more than the threshold value th1 (first threshold value), equal to or more than the threshold value th1 (first threshold value), and less than the time based on the height H0 (distance information). If it is less than the threshold value th2 (second threshold value), it is determined that a change in the road surface condition of the road has been detected.

According to the present embodiment, the vehicle detector 1 is installed in the sky above the road, and has an ultrasonic head portion 10 that transmits ultrasonic waves toward the road surface R of the road facing the road and receives the reflected waves of the ultrasonic waves. It includes a vehicle sensing unit 21 that acquires a reflection arrival time and detects a vehicle V traveling on the road surface R based on the acquired reflection arrival time. Then, the vehicle sensing unit 21 determines that the vehicle V has been detected when the distance information from the ultrasonic head unit 10 to the road surface R is set and the reflection arrival time is less than the threshold value th1, and the reflection arrival time is determined. When the threshold value is th1 or more and less than the threshold value th2, it is determined that the change in the road surface state of the road surface R has been detected.

When the vehicle detector 1 is configured as described above, it is possible to detect changes in the road surface condition of the road surface R such as flooding and snow cover. Therefore, the reflected wave when the vehicle V is not detected can also be effectively used. Further, since the change in the road surface condition such as flooding can be detected only by the vehicle detector 1, it is not necessary to separately provide a device or the like for detecting flooding or the like. Further, by setting the threshold value th2, it is possible to determine the change in the road surface state without erroneously determining the road surface R even if the calculation accuracy of the reflection arrival time is low.

Further, the vehicle detector 1 further includes a temperature sensor 23 that detects the ambient air temperature of the ultrasonic head unit 10, and the vehicle detector 21 further includes a threshold th1 and a threshold th2 based on the ambient temperature detected by the temperature sensor 23. I am correcting. By doing so, it is possible to use a threshold value corrected for the speed of sound that changes with temperature. Therefore, it is possible to accurately determine changes in the vehicle and road surface conditions.

Further, since the vehicle sensing unit 21 outputs an alarm when it determines that it has detected a change in the road surface condition of the road, it is possible to take measures such as closing the road when the vehicle becomes unsuitable for traffic.

In the above-described embodiment, only one second threshold value is set, but a plurality of second threshold values may be set. By setting a plurality, the degree of urgency can be determined step by step. The alarm at that time identifies, for example, which threshold value has been exceeded if the second threshold value is set at a time corresponding to three heights of 20 cm, 30 cm, and 40 cm from the road surface R. Information should also be included. Further, if the second threshold value is not set and the time is equal to or more than the first threshold value and less than the time when the ultrasonic wave is reflected by the road surface R, an alarm may be output. That is, the reflection arrival time (information about time) is equal to or greater than the threshold value th1 (first threshold value), and the ultrasonic head unit 10 calculated based on the height H0 (distance information) transmits ultrasonic waves before the road. If it is less than the time to receive the reflected wave reflected by the above, it may be determined that the change in the road surface condition of the road has been detected.

Further, in the above-described embodiment, the threshold value is set in time with respect to the reflection arrival time, but the reflection arrival time may be converted into a distance and the threshold value may be set in distance.

(Second Embodiment)
Next, the alarm system according to the second embodiment of the present invention will be described with reference to FIGS. 8 to 9. The same parts as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The present embodiment is an alarm system 100 including the vehicle detector 1 described in the first embodiment. As shown in FIG. 8, the warning system 100 includes a vehicle detector 1, a monitoring device 30A, and a road information control device 50.

The vehicle detector 1 transmits an alarm (alarm information) to the monitoring device 30A in the present embodiment in addition to the vehicle detection information described in the first embodiment. It is preferable that a plurality of vehicle detectors 1 are provided as shown in FIG. Of course, the plurality of vehicle detectors 1 shown in FIG. 8 are installed on different roads and points.

The monitoring device 30A collects the received alarm information and transmits the collected alarm information to the road information control device 50 in addition to the function of the tracan server 30 described in the first embodiment. That is, the monitoring device 30A functions as a collecting device that collects alarm information (alarm information) transmitted from the plurality of vehicle detectors 1.

In the present embodiment, the vehicle detector 1 and the monitoring device 30A are connected by a communication line such as a dedicated line N1 or a public line N2. Both the dedicated line N1 and the public line N2 may be wireless communication or wired communication.

The monitoring device 30A has the function of the tracan server 30, and collects alarm information using the existing communication line as in the first embodiment. However, the monitoring device 30A is referred to as the tracan server 30. May be prepared separately. In that case, the above-mentioned dedicated line N1 or public line N2 may be used as a new communication line.

The road information control device 50 provides information to the information board 60, the disaster prevention radio 70, and the like based on the alarm information transmitted from the monitoring device 30A. That is, the road information control device 50 functions as a providing device that provides information based on the alarm information (alarm information) collected by the monitoring device 30A (collecting device).

Specifically, the road information control device 50 acquires a hazard map in advance, predicts a road that cannot be passed based on the hazard map and alarm information, and outputs the prediction result to the information board 60, the disaster prevention radio 70, or the like. Send. For example, regarding the installation position of the vehicle detector 1 to which the alarm information is output, the road where the same flooding is predicted at the position around the position by referring to the flood hazard map, the road where the alarm information is received, or the road Information indicating that the road is impassable or caution is transmitted to the information board 60 installed on the route to the road where the flood is predicted and the disaster prevention radio 70 in the area to which the road belongs.

Further, the alarm information may include a value obtained by converting the reflection arrival time or the reflection arrival time into a distance. By doing so, it is possible to obtain the actual depth of flooding together with the alarm information. For example, it is possible to determine that passage is impassable when the depth is deep and caution is given when the depth is shallow.

Further, by accumulating the alarm information in the road information control device 50, it is possible to detect a point that is easily flooded other than the point indicated as an underpass in the hazard map or the like.

The information board 60 is a display board installed for the purpose of providing information on traffic jams, traffic accidents, weather, etc. on the road, and is also called a road information board, a road information bulletin board, or a road information display device. The road information control device 50 and the information board 60 are connected by a predetermined communication line.

The disaster prevention radio 70 is a master station provided in an administrative agency, a slave station equipped with a loudspeaker provided at a predetermined point in the area under the jurisdiction of the administrative agency, and a door-to-door receiver installed in a facility such as a residence. It is a well-known wireless system that is composed of and outputs information from the master station according to the area such as emergency information such as disaster warnings and warnings by the loudspeaker station and the door-to-door receiver as voice information or text information. is there.

The monitoring device 30A and the road information control device 50 may be installed in the same facility. Further, the road information control device 50 provides information not only to the information board 60 and the disaster prevention radio 70, but also to a traffic control center (police) or a road manager, or a vehicle (driver) through VICS (registered trademark). You may go to.

FIG. 9 shows another embodiment of the alarm system. In FIG. 9, the vehicle detector 1 transmits alarm information and the like to the management device 30B.

The management device 30B is installed, for example, at a road manager's office or the like. The management device 30B collects alarm information and the like from the vehicle detector 1 and presents them to the road manager and the like. The road manager changes the display of the information board 60 and reports to related organizations based on the alarm information collected by the management device 30B. That is, in the example of FIG. 9, the collecting device and the providing device are integrated.

Although only one management device 30B is shown in FIG. 9, there may be a plurality of management devices 30B. That is, the vehicle detector 1 may transmit alarm information to a plurality of management devices 30B. In this case, the plurality of management devices 30B may be, for example, one is a national institution and the other is a local government.

Further, the management device 30B may have the function of the Tracan server 30, or may be a device for collecting alarm information. Therefore, the management device 30B and the vehicle detector 1 may also be an existing line or a new line.

According to the present embodiment, the alarm system 100 is installed on the road and is capable of outputting alarm information regarding changes in the road surface. A vehicle detector 1 and a monitor that collects alarm information transmitted from a plurality of vehicle detectors 1. It includes a device 30A and a road information control device 50 that provides information based on the alarm information collected by the monitoring device 30A. By doing so, it is possible not only to directly notify the alarm information but also to provide it as wide area information in combination with other information such as a hazard map. Therefore, it is possible to provide information based on the warning information by using the warning information indicating the change in the road surface condition such as flooding and snow cover.

Further, the road information control device 50 may provide information based on the alarm information to the information board 60 and the disaster prevention radio 70. By doing so, it is possible to reliably provide information to the organizations that need to be provided, such as the driver of the vehicle traveling on the road, the local government to which the road belongs, the residents, and the like.

The present invention is not limited to the above embodiment. That is, those skilled in the art can carry out various modifications according to conventionally known knowledge within a range that does not deviate from the gist of the present invention. As long as the vehicle detector and the alarm system of the present invention are still provided by such a modification, the modification is, of course, included in the category of the present invention.

1 Vehicle detector 10 Ultrasonic head unit 20 Controller 21 Vehicle detector unit (road information setting unit, acquisition unit, sensing unit)
23 Temperature sensor (Temperature detector)
30A monitoring device (collecting device)
30B management device (collection device, providing device)
50 Road information control device (providing device)
60 Information board (predetermined equipment)
70 Disaster prevention radio (predetermined equipment)
100 alarm system

Claims (5)

An ultrasonic head unit that is installed over a road and transmits ultrasonic waves toward the facing road and receives reflected waves of the ultrasonic waves.
An acquisition unit that acquires information on the time from when the ultrasonic head unit transmits the ultrasonic wave to when the reflected wave is received.
A sensing unit that detects a vehicle traveling on the road based on the information about the time acquired by the acquiring unit is provided.
The sensing unit
Distance information from the ultrasonic head unit to the road is set, and
If the information regarding the time is less than the first threshold value, which is a value related to the time as a reference for determining that the vehicle has been detected, it is determined that the vehicle has been detected.
The information about the time is equal to or more than the first threshold value and less than the time for the ultrasonic head unit calculated based on the distance information to receive the reflected wave reflected on the road after transmitting the ultrasonic wave. If, it is determined that a change in the road surface condition of the road has been detected.
A vehicle detector characterized by that. The sensing unit is a value equal to or more than the first threshold value and less than the time required for the ultrasonic head unit calculated based on the distance information to receive the reflected wave reflected on the road after transmitting the ultrasonic wave. A second threshold is set,
When the information regarding the time is equal to or greater than the first threshold value and less than the second threshold value, it is determined that a change in the road surface condition of the road has been detected.
The vehicle detector according to claim 1. A temperature detection unit for detecting the ambient temperature of the ultrasonic head unit is further provided.
The sensing unit corrects the first threshold value and the second threshold value based on the ambient temperature detected by the temperature detecting unit.
The vehicle detector according to claim 2. The vehicle detector according to any one of claims 1 to 3, wherein the sensing unit outputs warning information when it determines that it has detected a change in the road surface condition of the road. An ultrasonic head unit that is installed over a road and transmits ultrasonic waves toward the facing road and receives reflected waves of the ultrasonic waves.
An acquisition unit that acquires information on the distance to an object that reflects the ultrasonic waves based on the time from when the ultrasonic head unit transmits the ultrasonic waves to when the reflected waves are received.
A sensing unit that detects a vehicle traveling on the road based on the information regarding the distance acquired by the acquiring unit is provided.
The sensing unit
Distance information from the ultrasonic head unit to the road is set, and
If the information regarding the distance is less than the first threshold value, which is a value related to the reference distance for determining that the vehicle has been detected, it is determined that the vehicle has been detected.
When the information regarding the distance is equal to or greater than the first threshold value and less than the distance based on the distance information, it is determined that a change in the road surface condition of the road has been detected.
A vehicle detector characterized by that.

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