JPH06162387A - Traffic volume measuring instrument - Google Patents

Abstract

PURPOSE:To provide the traffic volume measuring instrument which can accurately measure the average speed of a vehicle despite of an inexpensive constitution. CONSTITUTION:This instrument is provided with existence detecting sensors S1 to S9 which are installed at plural measurement points and measure the time required for passage of each vehicle, a speed measuring sensor S10 which is installed at a measurement point 5 and measures the running speed of each vehicle, an average speed calculating part 1 which calculates the average speed of the vehicle at each measurement point at intervals of a measurement unit time basing on a preliminarily determined average vehicle length L and outputs of existence detecting sensors S1 to S9, and a correction part 1 which corrects the value of the average vehicle length L at every correction interval time basing on the output of the speed measuring sensor S10 and the output of the existence detecting sensor S5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to traffic for measuring the traffic volume per measurement unit time, the time occupation rate of a vehicle occupying a road, the average speed of the vehicle, etc., based on the output of a presence detection type sensor. The present invention relates to a traffic volume measuring device, and more particularly, to a traffic volume measuring device capable of correcting an average vehicle length of a vehicle as necessary and measuring a vehicle average velocity more accurately without using many speed measurement type sensors.

[0002]

2. Description of the Related Art In order to measure the traffic volume of a vehicle traveling on a road, a presence detecting sensor has been conventionally used. FIG. 5 shows a vehicle detection area d by the presence detection type sensor 21.
The relationship between [m] and the vehicle 22 traveling on the road is illustrated. The vehicle 22 is traveling from the left to the right in FIG. 5, and the detection signal rises when the leading portion of the vehicle reaches the detection area, and falls when the vehicle finishes passing through the detection area.

With respect to such a detection signal, when the number of detection signals is counted over the measurement unit time, the number of running vehicles is grasped, and the time occupancy is grasped on the basis of the total ON time t of the detection signals. On the other hand, the speed V of each vehicle is
The predetermined average vehicle length L [m] and the detection area d
Based on [m] and the detection ON time t [ms], it is calculated as in (Equation 1). V = 3600 × (L + d) /
t [Km / h] (Equation 1) Further, the average speed V _H of the vehicle per measurement unit time is V _H = 3600 × (L + d) × N / (t ₁ + t ₂ + t ₃ + ... + t _N ). [Km / h] ... (Equation 2) is calculated. Here, N is the traffic volume per measurement unit time, and t _i [mS] is the detection ON time for the i-th vehicle.

[0004]

However, in the case of the conventional traffic volume measuring device, since the average vehicle length L [m] of the vehicle is a fixed value, the ratio of large vehicles at the actual measurement target point is planned. If the ratio is different from the ratio, there is a problem that it causes a measurement error of the calculated average speed. here,
For example, the average vehicle length L considering the ratio of large vehicles for each day of the week
Can be made variable, but in this case as well, the average vehicle length remains a fixed value, which is insufficient as a countermeasure.

On the other hand, in addition to the presence detection type sensor, a speed measurement type sensor can be installed at each place.
This is not appropriate as it will increase the equipment cost.
The present invention has been made in view of this problem, and an object of the present invention is to provide a traffic volume measuring device that is capable of more accurately measuring the average speed of a vehicle while having an inexpensive configuration. .

[0006]

In order to achieve the above object, a traffic volume measuring device according to the present invention is installed at a plurality of measurement points and measures the time required for each vehicle to pass through each point. Based on a presence detection sensor, a speed measurement sensor installed in at least one of the above measurement points to measure the traveling speed of each vehicle, a predetermined average vehicle length and each output of the presence detection sensor Then, based on the average speed calculation means for calculating the vehicle average speed at each measurement point for each measurement unit time, the output of the speed measurement type sensor, and the output of the presence detection type sensor at that point, correction is made. It is characteristically provided with a correction means for correcting the value of the average vehicle length for each interval time.

[0007]

The presence detection type sensor is installed at a plurality of measurement points, and measures the time t _{j (i)} required for each vehicle to pass at each point i. The speed measurement type sensor is installed in at least one place j among the above measurement points and measures the traveling speed of each vehicle.

The average speed calculation means is a predetermined average vehicle.
Based on the length L and each output of the presence detection type sensor,
Vehicle average speed V at each measurement point for each measurement unit time_{H (i)}
To calculate. The calculation method is arbitrary, but for example, during measurement
T within_{j (i)}Sum of T _(i)And the number of passing vehicles N_(i)
Based on and, the vehicle average speed V at the measurement point i_{H (i)}Calculate
You can put it out.

The correction means operates every correction interval time to correct the value of the average vehicle length L. The specific correction method is not particularly limited, but for example, the average speed VS of the vehicle is obtained based on the output of the speed measurement sensor, and the average speed VS and the point that is the calculation result of the average speed calculation means. The average vehicle length L may be corrected by comparing the vehicle average speed V _{H (j)} at _j .

As described above, according to the present invention, the average vehicle length L is corrected every correction interval time, and therefore the calculated vehicle average speed V _{H (i)} has high accuracy. That is, even if the ratio between the large-sized vehicle and the small-sized vehicle changes, the value of the average vehicle length L changes in accordance with the change, so that a more accurate vehicle average speed V _{H (i)} is calculated at each measurement point. be able to.

[0011]

The present invention will be described in more detail based on the following examples. FIG. 1 is a block diagram showing a traffic volume measuring apparatus according to an embodiment of the present invention. This device includes presence detection type sensors S _{1 to} S installed at points 1 to 9.
₉ , an average speed for calculating the vehicle average speed V _{H (i)} at each point i by the output of each of the speed measurement type sensor S ₁₀ installed at the point 5 and the sensors S _{1 to} S _{10 and} the calculation described later. The calculation unit 1 and the like are included. As a traffic measurement device,
Besides, there are a part for calculating the traffic volume and the time occupancy rate, and a part for displaying the traffic condition. However, since these are the same as the conventional device, the description thereof is omitted.

FIG. 2 shows the installation locations of the respective sensors S _{1 to} S _10. The installation intervals of the presence detection type sensors S _{1 to} S ₉ are L [m], and the measurement section is 8 × L. [M] is shown. And the point 5 is this measurement section 8
Since it is a representative point (for example, a measurement intermediate point) of × L, the speed measurement sensor S ₁₀ is arranged. If there is an existing one, use it.

In FIG. 1, the presence detection signal is a signal that maintains the H level from when the vehicle reaches the detection area of the sensor until when the vehicle finishes passing through the detection area (see FIG. 5).
Also, the speed detection signal is turned on in proportion to the speed of the traveling vehicle.
It is a signal that changes in time or a signal that includes speed information from the double sensor. Next, regarding the traffic volume measuring device configured as shown in FIG. 1, the average vehicle length L of the traveling vehicle is
Will be described and a procedure for calculating the average speed V _{H (i)} of the vehicle will be described (see FIG. 3, etc.).

The average speed calculation unit 1 detects the presence detection sensor S _i (i = 1) at every sampling time (for example, 20 mS).
~ 9) Output the presence detection signal and detect ON
The time t _{j (i)} (see FIG. 5) and the like are measured, and the total number T _(i) of passing vehicles N _(i) and detection ON time t _{j (i)} is calculated for each point i. Further, at the point 5, the traveling speed of each vehicle is calculated based on the output of the speed measurement sensor S ₁₀ .

Then, when the measurement unit time (for example, 5 minutes) is reached, the average speed calculator 1 determines each point i (i is 1 to 9).
Each point i based on the total sum N _(i) of the traveling vehicles in T and the total sum T _{(i )} = t _{1 (i)} + t _{2 (i)} + ... + t _{j (i)} + ... The average speed _{VH (i)} is calculated for each (see steps ST1 to ST4 in FIG. 3). That is, the average velocity V _{H (i)} at the point _i is V _{H (i)} = (L + d) × N _(i) × 3600 / T _(i) (Equation 3), and based on (Equation 3) Then, the average velocity V _{H (i)} at the points 1 to 9 is calculated. In addition, d is a detection area [m]
And L is the average vehicle length [m], but the initial value L ₀ is used for the average vehicle length L in the first calculation.

Next, the average speed calculation unit 1 uses the vehicle average speed VS ₍₅₎ at the point 5 calculated based on the output of the speed measurement type sensor S ₁₀ to calculate the average vehicle length according to (Equation 4). The value L + d in the + detection region is corrected (step ST5). L + d = VS ₍₅₎ × T ₍₅₎ / (N ₍₅₎ × 3600) (Equation 4) Note that T ₍₅₎ is the sum of the detection ON time t _{j (5)} at the point 5 and T _{( 5)} = t _{1 (5)} + t _{2 (5)} + …… + t _{j (5)} + ……
Given in.

In this way, the value of the average vehicle length L is corrected based on the data in the current measurement unit time, so that in the next measurement unit time, the step ST1 is performed based on the corrected average vehicle length L. The calculation of step ST4 is performed, and then the value of the average vehicle length L is corrected again by the process of step ST5. In the description of FIG. 3, the average vehicle length L is corrected for each measurement unit time, but the present invention is not limited to this. For example, an integer multiple of the measurement unit time may be used as the correction interval. good.

FIG. 4 shows a case where the average vehicle length L is corrected every five measurement unit times, and the initial correction interval time TH1 (T1 to T5) is based on the initial value L ₀ . The average speed VH1 is calculated based on the average vehicle speed VH1 in the second correction interval time TH2 (T6 to T10) based on the average vehicle length L corrected by (Equation 4).
To calculate. The same applies to the subsequent steps.

[0019]

As described above, in the traffic volume measuring device according to the present invention, the vehicle is obtained by arranging the speed measurement type sensor at a representative point in the traffic volume measurement section and obtaining the output from the presence detection type sensor. The average vehicle length at that time is calculated by matching the average speed and the vehicle average speed obtained based on the output of the speed measurement sensor for each correction interval time. Then, from the next measurement, the vehicle average speed at each measurement point is calculated based on the average vehicle length,
It is possible to obtain a highly accurate vehicle average speed that follows the ratio of large vehicles. In addition, the device can be constructed at low cost because only one speed measurement type sensor is required.

[Brief description of drawings]

FIG. 1 is a block diagram of a traffic volume measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the locations of the presence detection type sensor and the speed measurement type sensor.

3 is a flow chart for explaining the operation of the apparatus of FIG.

FIG. 4 is a view for explaining another operation of the apparatus of FIG.

FIG. 5 is a diagram illustrating a relationship among a presence detection sensor, a passing vehicle, and a detection signal.

[Explanation of symbols]

1 Average speed calculation unit (average speed calculation means,
Correction means) S _{1 to} S ₉ presence detection type sensor S ₁₀ speed measurement type sensor

Claims (1)

[Claims] 1. A presence detection sensor installed at a plurality of measurement points for measuring the time required for each vehicle to pass through each point; and each vehicle installed at at least one of the measurement points. An average speed that calculates the vehicle average speed at each measurement point for each measurement unit time based on the speed measurement sensor that measures the traveling speed of the vehicle, and the predetermined average vehicle length and each output of the presence detection sensor. And a correction unit that corrects the value of the average vehicle length for each correction interval time based on the output of the speed measurement sensor and the output of the presence detection sensor at that point. Traffic measurement device.