JPS6032240B2 - Vehicle presence counting device - Google Patents

Description

[Detailed Description of the Invention] The present invention aims to provide a device for measuring the number of existing vehicles that can automatically measure the density and number of existing vehicles at a certain point in time of vehicles passing through an arbitrary section such as a road or tunnel. It is something.

Conventionally, it is the first method to measure how many vehicles are present at a given moment in a tunnel section or a road section without intersections.
The integral method shown in the figure was a typical example.

In FIG. 1, 1 indicates a tunnel, etc., the length of the section is L, and the arrow indicates the direction of travel of the vehicle. 2 and 3
are vehicle detectors at the entrance and exit of a section L such as a tunnel, which count the number of passing vehicles when they pass through that position.

4 is an integrator that counts the number of sections existing based on the information on the number of passing vehicles, and the entrance sensor information is used for addition and the exit sensor information is used for subtraction.

The principle of this method is shown in equation 1. QT=J3(qi-
q.

)dt+k. ...1 In this formula, QT is the number of vehicles existing in the section at the moment of time T, qi is the count information of the entrance vehicle sensor, and q. is the exit vehicle sensor count information, k. indicates the initial number of devices existing at the time of starting measurement. The biggest drawback of this method is qi and q.

A small counting error of k. The problem is that this results in a large error in the QT value.
In general, vehicle detectors at entrances and exits have an unavoidable error of less than a few percent due to the trajectory of the vehicle and the special shape of the vehicle. However, as long as we use an integration method such as Equation 1, the initial value k will have an error of less than a few percent. The actual situation was that the error would accumulate and cause a large error if used for a long time, making it impractical. The present invention eliminates these drawbacks and will be described below with reference to the embodiment shown in FIG.

In Figure 2, 5 indicates a tunnel, etc., and its section length is L.
, the direction of travel of the vehicle is indicated by an arrow. Although this figure shows only one-way roads, a two-way road can also be constructed in exactly the same way. Reference numerals 6 and 7 are entrance and exit vehicle detectors, respectively, which have the same functions as the conventional example.

Reference numeral 8 denotes a speedometer for measuring the average speed of passing vehicles, and although it is shown near the middle of the section, it may also be installed near the entrance or exit.

Reference numeral 9 denotes a number-of-vehicles determination unit, which determines whether the traffic flow within the section is normal or abnormal based on the information of 6, 7, 8, and the section length L, and measures the traffic density and the number of vehicles present.

The measurement principle of this method is shown in Equations 2 and 3.

QT=ノさ(qi-q.)dt+light-,...
■kT-. ...Tei Seri Sankan-L --- (31) or kT-, niQT-, ...(32) In this formula, QT, qi, q. is the same as shown in Equation 1, but the content of kT-, is important. kT-, has two types of calculation formulas as shown in (31) and (32), and the initial value is calculated using formula (31) while the traffic flow is determined to be normal, and when the traffic flow is abnormal. If it is determined, an initial value is set using equation (32).

q(T-1) in equation (31) is the previously measured q and q. v(T-1) means the average speed measured last time. Therefore, q(T-1)/v(
T-1) is the traffic density measured last time. L is the section length shown in FIG. QT-, in equation (32) is the number of vehicles existing in the section measured last time, and this value is used as the initial value after the transition from normal to abnormal state. Furthermore, when the state changes from abnormal to normal, the equation (31) is used again. The determination of normal and abnormal state is qi, q. and v information. For the value of T, one unit is an arbitrary time width of 5 minutes to 6 days. Therefore, when the passing traffic flow is normal, the number of existing vehicles is calculated from the measurement of traffic density, so it is possible to determine the number of vehicles without accumulating errors.

From the time an abnormality is discovered in the traffic flow, the previous number of existing vehicles is used as the initial value for integration, so there is no cumulative error over a long period of time as in the past, and sufficient accuracy can be obtained for practical use. Furthermore, if the abnormal condition is restored to normal, the device automatically shifts to traffic density measurement, so continuity can be maintained.
As described above, it is possible to measure the density and the number of existing devices without cumulative error even in a relatively long section with the minimum equipment configuration, which is advantageous from the viewpoint of cost and maintenance management.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram of a conventional vehicle existing number measuring device, and FIG. 2 is a principle diagram of a vehicle existing number measuring device according to an embodiment of the present invention. 5...Tunnel, 6...Entrance vehicle sensor, 7...Exit vehicle sensor, 8...Speed meter, 9... Existence number determination unit. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. An entrance vehicle sensor that detects the number of passing vehicles at the entrance of a measurement section such as a road, an exit vehicle sensor that detects the number of passing vehicles at the exit of the measurement section of the road, etc.; a speedometer located within the measurement section to detect the speed of passing vehicles;
A traffic flow determining means for determining whether the traffic flow is normal or abnormal based on the correlation between the detected values of the entrance vehicle sensor, the exit vehicle sensor, and the speedometer; In some cases, the number of existing vehicles is determined by the following formula using the value obtained by multiplying the previously measured traffic density by the above-mentioned measurement section, and when an abnormality is determined, the number of existing vehicles in the section previously measured is used as the initial value, respectively. A device to measure the number of vehicles present. Q_T=∫^T_o(q_i-q_o)dt+k_T_
-_1 However, q_i is the count value of the entrance vehicle sensor, q_
o is the count value of the exit vehicle sensor, t is the time, k_T_-_
1 is the initial value.