JPH10340391A - Traveling vehicle identification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To identify the large size and small size of two vehicles parallelly traveling on two lanes by calculating the parallel traveling vehicle length of both measurement stops by a signal width and a car speed when a parallel traveling state is detected. SOLUTION: A prescribed distance between the measurement spots P1 and P2 is defined as L, the time equivalent to the time difference of the vehicle passing of both photoelectric sensors is defined as W0 , the signal widths of the vehicle passing time are defined as W1 and W2 and the estimated vehicle length (1), car speeds V1 and V2 and average car speed of the traveling vehicle are calculated from an expression (1)=L.2/W0 /(1/W1 +W2 ). An upper limit car speed Vu at a second measurement spot based on the average car speed in considering it as single acceleration traveling in judging acceleration to be W1 -W2 >=δ (δ is a positive constant) and the upper limit car speed VD at a first measurement spot based on the average car speed in considering it as single deceleration traveling in judging deceleration to be W2 -W1 >=δ are calculated. In the case of W1 -W2 >=δ, V2 >VU, W2 -W1 =δ and V1 >VD, the passing of both measurement spots in the parallel traveling state of the vehicles on the two lanes is detected, the parallel traveling car length at both measurement spots is calculated and the large size and the small size of both vehicles are identified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling vehicle discriminating apparatus for discriminating a traveling vehicle on a two-lane road such as a motorway from a non-contact state and discriminating a traveling vehicle from a traveling vehicle.

[0002]

2. Description of the Related Art Conventionally, on a motorway or the like, it is necessary to collect real-time information on traffic conditions for traffic information services and traffic control to keep traffic flowing smoothly, or to collect measurement information for tunnel ventilation control. 2. Description of the Related Art Measuring the momentary traffic volume at a predetermined monitoring point on a road is performed.

[0003] The traffic volume is measured by classifying the traveling vehicles (mainly automobiles) into large and small vehicles according to their lengths, and obtaining the number of large and small vehicles traveling for one minute, for example, and the average vehicle speed. Will be

[0004] At that time, conventionally, the length of a traveling vehicle passing through the monitoring point is measured by non-contact measurement using a loop coil type or ultrasonic type device to discriminate large and small vehicles.

First, a loop coil type device embeds a loop coil in a road, detects a change in inductance of the loop coil when the vehicle passes, and determines the length of a traveling vehicle (passing vehicle) from the change in a non-contact manner. By measuring, the large and small traveling vehicles are identified.

An ultrasonic apparatus is formed by attaching an ultrasonic head (transceiver) to a large structure such as a tall support pole along a road or an arm extending in a direction crossing the road, and is formed above a traveling vehicle. A pulse is periodically emitted from the head to the road surface, the passage of the traveling vehicle is detected from the change in the reception time of the reflected wave, and the length of the traveling vehicle is measured in a non-contact manner. .

[0007] However, in the case of the conventional loop coil type or ultrasonic type device, non-contact measurement of the length of a traveling vehicle can be performed, but both are large-scale devices. Regulations and the like are required, and once installed, it is not possible to easily move or the like, and it is not possible to flexibly conduct a traffic survey or the like at an arbitrary monitoring point at an arbitrary time.

Accordingly, the present applicant has filed Japanese Patent Application No. 9-8612.
According to the application of No. 7, a photoelectric sensor is provided at two roadside points (first and second measurement points) separated by a predetermined distance longer than a predicted maximum vehicle length on a road, the light receiving signal of which changes in level due to shading based on vehicle passage, A measuring and calculating device for processing the light receiving signals of the two photoelectric sensors is provided. The measuring and calculating device monitors the level change of the light receiving signals of the two photoelectric sensors and detects a shift in the detection timing of the passage of the vehicle by the two photoelectric sensors and a change in the timing of the two photoelectric sensors. A means for detecting the signal width of the vehicle passing time of the light receiving signal, l 'the vehicle length of the traveling vehicle, L' the predetermined distance, and W the time corresponding to the time difference between the vehicle passages of the two photoelectric sensors (detection timing shift). ₀ ', the signal width of the vehicle passing time of Ryohikariden sensor W _1', and W ₂ ', already filed a traveling vehicle measuring apparatus provided with means for calculating the vehicle length of the traveling vehicle from the following equation number 2 ing.

[0009]

[Number 2] l '= L' · 2 / W 0 '/ (1 / W 1' + 1 / W 2 ')

[0010] The running vehicle measuring device of this patent application embeds a loop coil in a road like a conventional loop coil type device or supports it at a high place like a conventional ultrasonic type device. Without a predetermined distance L ', a photoelectric sensor is provided at a relatively low position where light is blocked when the vehicle passes two points along the road, and installation and removal can be easily performed.

Then, the predetermined distance L 'is set longer than the predicted maximum vehicle length of the traveling vehicle, and the single traveling vehicle passes through both photoelectric sensors one by one without passing over both photoelectric sensors. The light reception signals of the two photoelectric sensors are changed by the passage, the predetermined distance L 'and the average vehicle speed V' ｛= (V ₁ '+ V ₂ ') / 2, V ₁ ', V ₂ ' between the two photoelectric sensors of the traveling vehicle.
Is a time difference W ₀ ′ (= L) corresponding to a difference in detection timing depending on the instantaneous vehicle speed と き when passing through both photoelectric sensors.
'Sequentially levels vary), each signal width W ₁ of Ryohikariden sensor based on the level change' ₁ / V, W ₂ 'is vehicle length l' depending on the vehicle speed V ₁ 'V _2' W ₁ '= 1 /
V ₁ ′ and W ₂ ′ = 1 / V ₂ ′.

Therefore, based on the detection of the time W ₀ ′ and the signal widths W ₁ ′ and W ₂ ′, the vehicle length 1 ′ is calculated and obtained from the equation (2), and a simple configuration that can be easily installed and removed. The vehicle length 1 'of the traveling vehicle can be measured in a non-contact manner, and the vehicle length 1' can be used to determine the size of the traveling vehicle, small or large, and to measure another large or small traffic volume. Measurement of traffic volume and the like can be performed flexibly at any monitoring point.

[0013]

In the case of the above-mentioned apparatus, the following problems arise when attempting to collectively measure and identify vehicles traveling in both lanes on a two-lane road.

That is, a total of two lanes is provided between the two photoelectric sensors.
In a parallel running state in which two vehicles run side by side, the parallel running state cannot be distinguished from the single running state of one vehicle. Therefore, the parallel state of the two vehicles is detected to identify the large and small vehicle types. There is a problem that cannot be done.

When a total of two vehicles in two lanes pass between the two photoelectric sensors in a running state of catching up or overtaking, for example, in the case of catching up, one vehicle (a point in front of the two photoelectric sensors) is located at two points. Although two vehicles pass in a shifted state, two vehicles pass in parallel at the other point (point ahead).

At this time, the light receiving signal of the photoelectric sensor at one point is intermittently formed at intervals of a predetermined time difference or less and has a signal width of 2 for each vehicle. The signal width of each signal cannot be obtained.

In the case of overtaking, a state similar to the above-described case occurs in which the preceding point is one point and the preceding point is the other point.

Therefore, there is a problem that even during a running state of catching up or overtaking, this running state cannot be detected, and it is not possible to discriminate between large and small vehicle types of the two running vehicles.

According to the present invention, two-lane vehicles are collectively measured by non-contact measurement using a photoelectric sensor so that large and small vehicle types of two vehicles running in parallel with two lanes can be identified. That is the task. It is another object of the present invention to be able to identify large and small vehicle types of a total of two vehicles in two lanes in a running state of catching up or overtaking.

[0020]

According to a first aspect of the present invention, there is provided a traveling vehicle identification apparatus, comprising: a first vehicle in a traveling direction separated by a predetermined distance longer than a predicted maximum vehicle length of a two-lane road; 1, a photoelectric sensor provided at a second measurement point, the level of a light reception signal changes due to light blocking based on vehicle passage, and a measurement calculation device for processing the light reception signals of both photoelectric sensors. Means for monitoring and detecting a change in the level of the light reception signals of both photoelectric sensors, L being the predetermined distance, W _{0 being} the time corresponding to the time difference between the two photoelectric sensors passing through the vehicle, and the signal width of the vehicle passing time of both photoelectric sensors Where W ₁ and W ₂ are used to calculate the estimated vehicle length l of the traveling vehicle from the following equation (3), the estimated vehicle length l and both signal widths W ₁ and W 2
₂ means for calculating the vehicle speeds V ₁ and V ₂ at both measurement points and calculating the average of both vehicle speeds V ₁ and V ₂ as an average vehicle speed; and W ₁ −W ₂ ≧ δ (δ is a positive constant) acceleration calculating the upper limit vehicle speed V _U at the second measurement point based on the average vehicle speed when considered alone acceleration running during determination, when considered alone deceleration during determination W ₂ -W becomes ₁ ≧ [delta] deceleration comprising Means for calculating the upper limit vehicle speed V _D at the first measurement point based on the average vehicle speed of W ₁ -W ₂ ≧ δ and V ₂ > V _U or W ₂ -W ₁
Means for detecting that a vehicle having two lanes has passed through both measurement points in a parallel running state when ≧ δ and V ₁ > V _D , a signal width W ₁ , W ₂ and a vehicle speed V when the parallel running state is detected _1, V ₂ and by calculating the parallel running vehicle length at both measurement point, both the parallel running vehicle length and large, the two vehicles running parallel by comparison with the combination length of small standard vehicle length large, small Means for identifying the type of vehicle.

[0021]

## EQU3 ## 1 = L ・ 2 / W ₀ / (1 / W ₁ + 1 / W ₂ )

Then, the first and second measurement points P ₁ , P ₂
In a parallel running state where two vehicles in two lanes pass side by side,
Based on the vehicle speed and the difference in running state such as acceleration and deceleration, etc., there is a difference in the time when the two vehicles running in parallel pass through both photoelectric sensors, and the signal widths of the light receiving signals of both photoelectric sensors are different.

On the other hand, when one vehicle travels independently in one lane and passes the first and second measurement points, it passes through both photoelectric sensors in an acceleration or deceleration state. The signal width of the light receiving signal is different.

For this reason, in the present invention, first, it is considered that the light receiving signals of both photoelectric sensors have changed in level when one vehicle travels alone, and the signal widths W ₁ and W ₂ of the light receiving signals of both sensors are expressed as follows: by the time corresponding W ₀ to the deviation of the level change timing (time difference of the vehicle passing), and calculates the vehicle speed (average vehicle speed) in the same manner as the foregoing patent application.

Next, if the vehicle is traveling alone in an accelerated state, since W ₁ > W _{2 due} to acceleration, W ₁ −W ₂ ≧ δ
It was determined acceleration running state conditions, during acceleration determination, based on the average vehicle speed, one vehicle is calculated the speed of the second measurement point when traveling at maximum acceleration as upper speed V _U.

In the case of single traveling in a deceleration state, since W ₂ > W ₁ due to deceleration, it is determined that the vehicle is in a deceleration traveling condition on the condition of W ₂ −W ₁ ≧ δ. based on, one vehicle to calculate the vehicle speed at the first measurement point when traveling at maximum deceleration upper limit vehicle speed V _D.

If the vehicle is traveling alone, W ₁ −W ₂ ≧
It is impossible that V ₂ > V _U during the acceleration state of δ.
It is impossible that V ₁ > V _D during the deceleration state of ₂₋ W ₁ ≧ δ.

Therefore, if W ₁ −W ₂ ≧ δ and V ₂ > V _U or W ₂ −W ₁ ≧ δ and V ₁ > V _D , it is detected that the two-lane vehicles are running in parallel. .

Then, when the parallel running state is detected, the parallel running length at each of the first and second measurement points is compared with the combined length of the large and small reference vehicle lengths, and the two parallel running large and small vehicle lengths are compared. Identify small car models.

Therefore, the apparatus according to the first aspect of the present invention can detect the parallel running state of a vehicle having two lanes, which has been impossible in the related art, and can distinguish between the two large and small vehicles.

According to the second aspect of the present invention, the vehicle is provided at the first and second measurement points in the traveling direction separated by a predetermined distance longer than the predicted maximum vehicle length of the two-lane road, and the vehicle passes therethrough. A photoelectric sensor that changes the level of the received light signal due to shading based on the light-receiving signal, and a measurement and calculation device that processes the received light signals of both photoelectric sensors. The measurement and calculation device monitors the change in the level of the received light signal of both photoelectric sensors. Detecting means for detecting that a two-lane vehicle has passed both measurement points in a running state of catching up or overtaking when at least one of the light receiving signals of both photoelectric sensors is intermittent at a signal interval of a predetermined time difference or less. Means for detecting, at the time of this detection, the other light receiving signals of the two photoelectric sensors in accordance with the ratio of the two signal widths obtained by the intermittent operation of the one light receiving signal of the two photoelectric sensors. Means for calculating the length of each of the two lanes of the vehicle based on the two signal widths based on the passage of the two light-receiving signals through the same vehicle, and the predetermined distance and the time difference between the passage of the vehicles by both photoelectric sensors; Means for discriminating large and small vehicle types of two vehicles running in a running state of catching up or overtaking by comparing the vehicle length of the vehicle with a large or small reference vehicle length.

If the two-lane vehicle travels in a running state of catching up or overtaking, for example, in a running state of catching up, the two vehicles pass through the first measurement point in front of the vehicle and deviate from the first measurement point. The vehicle passes through the second measurement point in a parallel running state.

At this time, the light receiving signal of the photoelectric sensor at the first measurement point is intermittently arranged at short intervals, becomes a signal of two signal widths corresponding to the passage of each of the two vehicles, and becomes the signal of the second measurement point. The light receiving signal of the sensor becomes a signal of one signal width corresponding to the passage of two vehicles running in parallel.

If the vehicle is passing, the two vehicles pass in parallel with the first measurement point, pass through the second measurement point, and pass through the second measurement point. Is intermittent as the two vehicles pass.

Therefore, in the present invention, when one of the light receiving signals of the two photoelectric sensors is interrupted at short intervals, the running state of catch-up or overtaking is detected.

Then, when this running state is detected, the light receiving signal based on the detection of the parallel running state of the other photoelectric sensor is converted into two signal widths by the ratio of the two signal widths generated by the intermittent light receiving signal of one photoelectric sensor. To divide.

Further, one of the two signal widths having the same ratio of the light receiving signals of both photoelectric sensors is defined as a two signal width based on the passage of one vehicle, and the other two signal width is defined as a two signal width based on the passage of the other vehicle.
The vehicle length is calculated based on these two signal widths in the same manner as in the case of the single traveling state of the above-mentioned application.

Then, by comparing the calculated vehicle lengths with the large and small reference vehicle lengths, the large and small vehicle types of the two vehicles traveling in the overtaking / overtaking traveling state are identified.

Therefore, the apparatus according to the second aspect of the present invention detects a running state of catching up or overtaking a two-lane vehicle, which has been impossible in the past, and makes it possible to identify the two large and small vehicle types.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. First, FIG. 1 shows a block configuration of the apparatus. For example, photoelectric sensors 1a and 1b are installed at first and second measurement points separated by a predetermined distance in a vehicle traveling direction with a monitoring point of a motorway as an intermediate point.

In the case of the transmission type detection system, the two photoelectric sensors 1a and 1b are most simply provided with a light emitter 3 and a light receiver 4 on both sides (road side) of the road 2, as shown in FIG. Formed.

At this time, since the road 2 is composed of two lanes 2a and 2b going up or down, the photoelectric sensors 1a and 1b
Is composed of an infrared light sensor or the like having a long detection distance of about 10 m using an infrared LED or the like as a light source so as to cover the road-side distance in the transverse direction.

The predetermined distance between the first and second measurement points is set to be longer than the predicted maximum vehicle length of the traveling vehicle (predicted maximum vehicle length), for example, about 50 m.

As is clear from FIG. 2, the light emitters 3 and the light receivers 4 are located at relatively low positions so that the horizontal projection light from the light emitters 3 to the light receivers 4 is reliably blocked by the traveling vehicle 5. Supported by

Next, the light receiver 4 of the photoelectric sensors 1a and 1b
The received light signal changes into, for example, a low level and a high level by light input and light blocking, and is transmitted in real time to the input processing unit 7 of the measurement / operation device 6 having a computer configuration by wire or wirelessly.

The input processing unit 7 includes an amplifier, a filter, and the like, and transfers the received light signal from the photoelectric sensors 1a and 1b to the A / D conversion unit 8 after eliminating unnecessary noise and the like. The D conversion unit 8 samples the light receiving signals of the photoelectric sensors 1a and 1b at a predetermined sampling period of, for example, about 10 to 20 msec set in consideration of the measurement accuracy and the like, and performs A / D conversion.

The digital data of the light receiving signals of the photoelectric sensors 1a and 1b formed by the A / D conversion are sent to an arithmetic processing section 9 formed by a microcomputer, and the arithmetic processing section 9 performs processing based on the input digital data. The large and small vehicles that have passed through the first and second measurement points in the two lanes 2a and 2b are identified, and information on the number of vehicles and average speeds of large and small traveling vehicles, for example, every minute, according to this identification. Is formed as traffic volume measurement information, and this measurement information is supplied from the data output unit 10 to a subsequent display processing unit (not shown), an information storage unit (not shown), and the like, for example, a CRT display or a liquid crystal display. Display a trend graph and the like of the traffic volume for one minute on the monitor display device.

Next, the operation processing section 9 will be described.
First, the arithmetic processing section 9 performs software processing based on the execution of a program to determine the running state of single running, parallel running, overtaking / overtaking, and discriminate between two large and small vehicle types. To (ix).

(I) Means for monitoring and detecting a change in the level of the light receiving signal of the photoelectric sensors 1a and 1b.

(Ii) The predetermined distance between the measurement points P _{1 and} P ₂ is L, the time corresponding to the time difference between the _two photoelectric sensors 1a and 1b passing through the vehicle is W ₀ , and the vehicle passing time of the two photoelectric sensors 1a and 1b is Means for setting the signal width to W ₁ and W ₂ and calculating the estimated vehicle length l of the traveling vehicle from the following equation (4).

[0051]

## EQU4 ## 1 = L ・ 2 / W ₀ / (1 / W ₁ + 1 / W ₂ )

The (iii) The by the estimated vehicle length l and the signal width W _1, W ₂ calculates a vehicle speed V _1, V ₂ at the measurement point P _1, P _2, mean the average of both the vehicle speed V _1, V ₂ Means to calculate as vehicle speed.

(Iv) The second measurement point P ₂ based on the average vehicle speed when it is assumed that the vehicle is traveling alone (accelerated acceleration) when accelerating to satisfy W ₁ −W ₂ ≧ δ (δ is a positive constant). at cruising speed V _U calculates, W ₂ -W ₁ ≧ δ deceleration determination time to a single traveling of the deceleration state in which the (single deceleration) and the first measurement point P ₁ based on the average vehicle speed when considered in means for calculating the upper limit vehicle speed V _D.

(V) When W ₁ −W ₂ ≧ δ and V ₂ > V _U or W ₂ −W ₁ ≧ δ and V ₁ > V _D , a vehicle having two lanes is running side by side and both measurement points P ₁ means for detecting that has passed through the P _2.

(Vi) When the parallel running state is detected, the signal widths W ₁ and W
₂ and the vehicle speeds V ₁ and V ₂ , calculate the parallel running lengths at the measurement points P ₁ and P ₂ , and compare the two parallel running lengths with the large and small reference vehicle lengths to drive the two vehicles in parallel. Means to identify large and small vehicle types.

(Vii) When the light receiving signal of at least one of the two photoelectric sensors 1a and 1b is intermittent at a signal interval of a predetermined time difference or less, the vehicle having two lanes catches up and overtakes the two measuring points P _1. means for detecting that has passed through the P _2.

(Viii) At the time of detecting a running state of catch-up or overtaking, the other of the two photoelectric sensors 1a, 1b is determined according to the ratio of the two signal widths obtained by the intermittent operation of one of the light receiving signals of the two photoelectric sensors 1a, 1b. Of the light reception signal of 2
Means for dividing the signal width into two signal widths, and calculating the vehicle length of each of the two lanes of the vehicle based on the two signal widths based on the passage of the two light-receiving signals through the same vehicle, the predetermined distance L, and the time difference between the two photoelectric sensors 1a and 1b. .

(Ix) A means for comparing the calculated vehicle lengths of the two vehicles with the large and small reference vehicle lengths to determine the large and small vehicle types of the two vehicles traveling in the overtaking / overtaking running state.

Next, the processing of the arithmetic processing section 9 will be described. First, a description will be given of a process in the case where one vehicle travels alone on one of the two lanes 2a and 2b and passes through the photoelectric sensors 1a and 1b.

As shown in FIG. 3A, the photoelectric sensor 1
The interval between the first and second measurement points P ₁ and P ₂ where a and 1b are located, that is, the predetermined distance is L [m].

The vehicle length and the vehicle speed (instantaneous vehicle speed) of the traveling vehicle 5 at the measurement point P ₁ are set to l _1a [m] and V ₁ [km / h], and the vehicle at the measurement point P ₂ of the vehicle 5 is measured. The length and vehicle speed (instantaneous vehicle speed) are l _2a [m] and V ₂ [km / h], and the average vehicle speed between the measurement points P ₁ and P ₂ is V [km / h]. In addition,
h is the hour.

Further, as shown in FIGS. 3B and 3C, the traveling vehicle 5 reaches the measurement points P ₁ and P ₂ , and the photoelectric sensors 1 a and 1 b change from the light incident state to the light shielding state. The times (entrance times) are t _1a and t _2a , and the traveling vehicle 5 is at the measurement point P
_1, P ₂ passing through the finished photoelectric sensor 1a, 1b returns to the receiving light again time (out time) of t _1a ', t _2a' and.

At this time, the light receiving signal of the photoelectric sensor 1a has a signal width W of a light shielding period (t _1a ′ −t _1a ) during which the traveling vehicle 5 passes through the photoelectric sensor 1a, as shown in the waveform of FIG.
₁ [sec] goes to the high level.
The light receiving signal b has a light shielding period (t _2a ′ −t) in which the traveling vehicle 5 passes through the photoelectric sensor 1b as shown in the waveform of FIG.
The signal width W ₂ [sec] of _2a ) becomes a high level.

The traveling vehicle 5 has the photoelectric sensors 1a and 1b.
, Ie, the photoelectric sensor 1a,
1b is the time corresponding to the time difference when the traveling vehicle 5 passes through W.
When ₀ [sec], the time W ₀ becomes t _2a '-t _1a' or t _2a -t _1a.

The predetermined distance L is set in advance, and the time W ₀ and the signal widths W ₁ and W ₂ are determined from the digital data of the A / D converter 8 based on, for example, the falling time t of the light receiving signals of the photoelectric sensors 1a and 1b. _1a ', t _2a' difference _{(t 2a '-t 1a')} , the period _{(t 1a '-t 1a),} (t 2a' obtained by measuring the -t _2a).

On the other hand, the average vehicle speed V is obtained from the following equation (5). In addition, 3.6 in a formula is unit [m / sec] and unit [k
m / h] (= 3600/1000)
It is.

[0067]

V [km / h] = L3.6 / W ₀ = (V ₁ + V ₂ ) / 2

The vehicle speeds V ₁ and V ₂ are measured at the measurement points P ₁ and V ₁ .
Based on the vehicle lengths l _1a and l _2a detected at P ₂ ,
It is shown by two formulas.

[0069]

V ₁ [km / h] = l _1a · 3.6 / W ₁ V ₂ [km / h] = l _2a · 3.6 / W ₂

Then, based on the equations (5) and (6), the following equation (7) is obtained.

[0071]

[Equation 7] _{L · 3.6 · 2 / W 0} = V 1 + V 2 = l 1a · 3.
6 / W ₁ + l _2a・ 3.6 / W ₂

Further, the following equation (8) is obtained from the equation (7).

[0073]

## EQU8 ## L · 2W ₀ = l _1a / W ₁ + l _2a / W ₂

Assuming that l _1a = l _2a = l in the equation (8), the estimated vehicle length l of the traveling vehicle 5 is the same as the following equation (9) similar to the equation (4). It can be obtained from the equation.

[0075]

[Equation 9] _{l [m] = L · 2} / W 0 / (1 / W 1 + 1 / W 2)

When the vehicle length 1 is obtained from the calculation of the above equations (5) to (9), the vehicle length 1 is compared with the large and small reference vehicle lengths to identify large and small vehicle types.

More specifically, in consideration of the detection of a running state of catch-up or overtaking, which will be described later, the shortest and longest reference vehicle lengths Smin [m] and Smax [m] of a small vehicle and the shortest and longest vehicle lengths of a large vehicle The reference vehicle lengths Lmin [m] and Lmax [m] are set in advance. Note that Smin <Smax <Lmin <Lmax.

The signal width W ₁ ,
Considering sampling error of W _2, based on the average vehicle speed V and the sampling error constant [delta] [sec], calculates an error adjustment length Δl of the numerical formula 10 following [m].

[0079]

Δl [m] = (V / 3.6) · δ

In the case of single traveling, the estimated vehicle length l is compared with the reference vehicle length Lmin. If l ≧ (Lmin−Δl), it is determined that the vehicle is large. If l <(Lmin−Δl), Identify as small.

Next, a case where two vehicles run in a parallel running state will be described. In this case, as shown in FIG. 4 (a), two vehicles 5a, 5b running in parallel are driven by the photoelectric sensors 1a, 1b, each having a vehicle length l _1b [m] and l _2b [m]. Of the photoelectric sensor 1a,
The light receiving signal of 1b indicates the entry times of the vehicles 5a, 5b at t _1b , t
_2b and the departure times are t _1b ′ and t _2b ′,
As shown in (c), it becomes high level during the light shielding periods (t _1b ′ −t _1b ) and (t _2b ′ −t _2b ) of the signal widths W ₁ [sec] and W ₂ [sec].

Then, assuming that the change in the signal level has occurred in one vehicle running alone and the estimated vehicle length is l [m], based on the vehicle length l and the signal widths W ₁ and W ₂ , The vehicle speeds V ₁ , V ₂ and the average vehicle speed V at the measurement points P ₁ , P ₂ are obtained from the following equations (11) and (12) corresponding to the equations (6).

[0083]

V ₁ [km / h] = 1.3.6 / W ₁ V ₂ [km / h] = 1.3.6 / W ₂

[0084]

V [km / h] = {l 3.6 / W ₁ + l
3.6 / W ₂ ｝ / 2

On the other hand, the distance between the measurement points P ₁ and P _{2 of} the distance L is 1
When the two vehicles travel in the limit acceleration state and the limit deceleration state, the acceleration / deceleration characteristics indicating the relationship between the traveling distance and the vehicle speed are shown by solid lines Ac and Bk in FIG.

With the acceleration / deceleration characteristics shown in FIG. 5, the measurement points P ₁ , P
Assuming that the vehicle traveling between the _two vehicle speeds is Vx [km / h], the acceleration characteristic traveling distance L for this vehicle speed Vx
_U [m], the deceleration characteristic travel distance L _D [m] is given by the following equation 1.
3 and Equation 14 respectively.

In the equation, a is a constant corresponding to the expected maximum vehicle speed, b and c are constants indicating change characteristics (slope) of acceleration and deceleration, and Ln is an operator indicating natural logarithm.

[0088]

L _u [m] = − b · Ln (1−Vx / a)

[0089]

L _D [m] = c · Ln (1−Vx / a) + a

Further, when the vehicle travels alone in the marginal acceleration state, it is the fastest at the second measurement point P ₂ and the upper limit vehicle speed V _U [km
/ H] becomes, when individually running at the limit deceleration state, the fastest in the first measurement point P _1, the upper limit vehicle speed V _D [km / h]
become. Then, based on the numerical formula 13, obtaining the upper limit vehicle speed V _U from several 15 expression below.

[0091]

V _U [km / h] = a · [1-exp ｛− (L _U
+ L / 2) / b]

[0092] However, when become a ≦ V _U is, a
= V _U + β ₁ (where β ₁ is a positive constant for upper limit correction) to determine the upper limit vehicle speed V _U. Further, based on the number 14 expression, determined from the number 16 wherein the upper limit vehicle speed V _D Hatsugi.

[0093]

V _D [km / h] = a · [1-expａ (L _D
−a−L / 2) / c｝]

However, if a ≦ V _D , a
= V _D + β ₂ (where β ₂ is a positive constant for upper limit correction) to obtain the upper limit vehicle speed V _D.

By the way, considering the positive constant δ for absorbing the sampling error, the signal widths W ₁ and W ₂ are determined during the acceleration traveling.
₁₋ W ₂ ≧ δ, and W ₂ −W ₁ ≧ δ during deceleration traveling.

If the vehicle is traveling alone, W ₁ −W ₂ ≧
average vehicle speed V at the time of accelerated running of the [delta] becomes less than the upper limit speed V _U, the average vehicle speed V during deceleration traveling of W ₂ -W ₁ ≧ δ is equal to or less than the upper limit vehicle speed V _D.

Therefore, when W ₁ −W ₂ ≧ δ and V> V _U or W ₂ −W ₁ ≧ δ and V> V _D from the calculation, two vehicles in two lanes are running in parallel. Both measurement points P ₁ ,
And identified as having passed the P ₂ for detecting the state.

When this parallel running state is detected,
Signal width W _1, W ₂ and the vehicle speed V _1, by the V _2, the parallel running vehicle length l _1b at the measurement point _{P 1, P 2 (= V} 1 /3.6 · W
₁ b), to calculate the _{l 2b (= V 2 /3.6 ·} W 2 b).

Further, based on the parallel vehicle lengths l _1b and l _2b and the large and small reference vehicle lengths Lmin, Smax and Smin, parallel running is performed based on the following discriminating conditions (a), (b) and (c). The combination of the two vehicle types is determined and detected.

(A) l _1b {= (V ₁ /3.6)·W ₁ }
> (Lmin + Smin -Δl) and _{l 2b {= (V 2/} 3.
6) If W ₂ ｝> (Lmin + Smin-Δl), 2
Both units are large vehicles.

(B) l _1b {= (V ₁ /3.6)·W ₁ }
> (Smax + Smin -Δl) and _{l 2b {= (V 2/} 3.
6) · W ₂ ｝> (Smax + Smin−Δl), where l _1b , l _2b <(2Lmin−Δl)}, the large vehicle 1
And a small car.

(C) l ₁ ｛= (V ₁ /3.6) ・ W ₁ ｌ
≧ (Smax−Δl) and l ₂ ｛= (V ₂ /3.6)·W
₂ ｝ ≧ (Smax−Δl), where l ₁ , l ₂ <(Lmin
+ Smax-Δl)｝, both are small cars.

Next, a case in which a two-lane vehicle travels in a running state of catching up or overtaking will be described. First,
As if to catch up is shown in FIG. 6 (a), the first measurement point P ₁ the preceding vehicle 5a, and sequentially passes through the vehicle 5b row after faster than the vehicle 5b is spaced, then, prior of the trailing vehicle 5b catches up to the vehicle 5a, the second measurement point P ₂ both vehicles 5a, 5b passes in parallel running state.

At this time, the light receiving signal of the first photoelectric sensor 1a has a signal width W ₁₁ [se from the entry time t _11c to the exit time t _11c ′ of the preceding vehicle 5c as shown in FIG. 6B.
c], the signal width W ₁₂ [sec] from the entry time t _12c to the exit time t _12c ′ of the following vehicle 5d becomes a high level, and the light receiving signal of the second photoelectric sensor 1b is (c) in FIG. As shown in the figure, the entry time t _2c of the parallel running state of both vehicles 5a and 5b
Signal width of up to time t _2c 'out of the W ₂ [sec] is at a high level.

In the case of overtaking, there are the following two cases. In the first case, as shown in FIG.
The first measurement point P ₁ the preceding vehicle 5a, of the trailing vehicle 5b
There passed in parallel running state, then the vehicle 5c overtaking vehicle 5d, after the vehicle 5d passes through the second measurement point P _2, a case where the vehicle 5c passes through the same point P _2.

In this case, as shown in FIG. 7B, the light receiving signal of the first photoelectric sensor 1c has a signal width W ₁ [sec] from the entry time t _1d to the exit time t _1d ′ of a group of vehicles. The signal becomes high level, and the light receiving signal of the second photoelectric sensor 1b has a signal width W ₂₁ [sec] from the entry time t _21d to the exit time t _21d ′ of the vehicle 5d and the vehicle 5c as shown in FIG.
Signal width W from the entry time t _22d to the exit time t _22d ′
₂₂ [sec] becomes high level.

[0107] The second case, as shown in (a) of FIG. 8, the first measurement point P ₁ a preceding vehicle 5c, trailing vehicle 5d passes sequentially, then the vehicle 5d is a vehicle 5c overtaking, then the vehicle 5d passes through the second measurement point P _2, a case where the vehicle 5c passes through the same point P _2.

At this time, as shown in FIG. 8B, the light receiving signal of the first photoelectric sensor 1a has a signal width W ₁₁ [sec] from the entry time t _11e to the exit time t _11e ′ of the preceding vehicle 5c. The signal width W ₁₂ [sec] from the entry time t _12e to the exit time t _12e ′ of the following vehicle 5d becomes high level, and the light receiving signal of the second photoelectric sensor 1b is as shown in FIG. And the vehicle 5d
From the input time t _21e to the _output time t _21e ′ W ₂₁ [se
c], the signal width W ₂₂ [sec] from the entry time t _22e to the exit time t _22e ′ of the vehicle 5c becomes high level.

By the way, one vehicle travels between the two measuring points P ₁ and P _{2 at the} limit acceleration (maximum acceleration) and the limit deceleration (maximum deceleration).
When the vehicle travels in the acceleration / deceleration state, the vehicle speed characteristics with respect to the traveling distance are as shown by the solid lines Ac and Bk in FIG. 5 as described above.

Then, in order to determine a vehicle speed difference at which the vehicle can catch up or overtake, _one of the two vehicles (preceding vehicle) that has passed the measurement point P1 at the same vehicle speed decelerates at the marginal deceleration and the other vehicle (the following vehicle). ) Accelerated at the limit acceleration.

At this time, the deceleration characteristic travel distance L _D [m] between the measurement points P ₁ and P ₂ based on the solid line Bk in FIG.
Represented by the formula similar to the formula, when the vehicle speed Vx and the average vehicle speed V, obtained in decreasing the number 17 equations of the average vehicle speed V Hatsugi, midpoint measurement point _{P 1, P 2 (L D} = L / 2 ).

[0112]

Equation 17] V [km / h] = a '· [1-exp {L D -
a ′) / c ′｝] where a ′ and c ′ in the expression are constants corresponding to a and c in the expression (14).

When the vehicle is running at a reduced speed, L
If the vehicle speed is the maximum speed V _D1 [km / h] on the deceleration side at the first measurement point P ₁ before / 2 [m], this maximum vehicle speed V _D1 is expressed by the following equation (18). You.

[0114]

V _D1 [km / h] = a ′ · [1-exp '(L
_D− a′−L / 2) / c ′)｝]

When the vehicle is traveling at a reduced speed, L / L
If the vehicle speed is the lower limit vehicle speed V _D2 [km / h] at the second measurement point P ₂ two meters ahead, the lower limit vehicle speed V _D2
Is represented by the following equation (19).

[0116]

V _D2 [km / h] = a ′ · [1-exp ｛(L
_D− a ′ + L / 2) / c ′｝]

[0117] On the other hand, equal speed of the vehicle to accelerated running and the vehicle to catch up, the first measurement point P ₁ in the deceleration which is the starting point of overtake, acceleration side vehicle speed of a vehicle acceleration running at this measurement point P ₁ Is lower limit vehicle speed V _U1 [km / h], lower limit vehicle speed V _U1 is equal to upper limit vehicle speed V _D1 and is expressed by the following equation (20).

[0118]

[ _Equation 20] V _U1 [km / h] = V _D1

At this time, the acceleration travel distance L _U [m] based on the solid line Ac in FIG. 5 is expressed by the following equation (21). Note that Ln in the expression is an operator indicating a natural logarithm.

[0120]

L _u [m] = − b ′ · Ln (1−V _D1 / a ′)

Then, the distance L from the first measurement point P ₁
When [m] destination of the second measurement point upper limit vehicle speed V _U2 [km / h] of the speed of the vehicle acceleration side to accelerate the running at P _2, the upper speed V _U2, based on the numerical formula 21, It is expressed by the following equation (22).

[0122]

V _u2 [km / h] = a ′ · [1-exp'−
(Lu + L) / b ′｝] However, when a ′ ≦ V _U1 , a ′ = V _U1 +
β ′, (β ′ is an upper limit correction coefficient).

Next, the initial speed is V ₁ [km / h] and the final speed is V
Assuming that ₂ [km / h], the travel distance Lt [m] during t [sec] is generally obtained from the following equation (23).

[0124]

Lt [m] = (V ₁ /3.6)·t+(1/
2) · {(V ₂ /3.6−V ₁ /3.6)/t}·t ²

Also, t [sec] is obtained from the following equation (24).

[0126]

[Equation 24] t [sec] = Lt · 3.6 / ｛V ₁ + (1 /
2) ・ (V ₁ −V ₂ )｝

Then, the distance L between the measurement points P ₁ and P ₂
[M] is the difference between the time required for one vehicle to travel in the marginal acceleration state and the time required for the other vehicle to travel the same distance L [m] in the marginal deceleration state. If this time is the delay determination time Dty [sec], this delay determination time Dty
Is represented by the following equation (25).

[0128]

Dty [sec] = L · 3.6 · [1 / ｛V _D1
+ (V _D2 −V _D1 ) / 2｝ −1 / ｛V _U1 + (V _U2 −V _U1 )
/ 2｝]

In the case of catch-up in FIG. 6, the time difference between the falling of the signal widths W ₁₁ and W ₁₂ at the first measurement point P ₁ in FIG. _12c '
−t _11c ′ =) WΔc [sec] must be WΔc ≦ Dty.

In the case of overtaking in FIG. 7, the time difference between the falling of the signal widths W ₂₁ and W ₂₂ at the second measurement point P ₂ in FIG. 7C, that is, the passing time difference (t _22d '-T
_21d ′ =) WΔd [sec] must be WΔc ≦ Dty.

In the case of overtaking in FIG. 8, WΔc ≦ Dty in FIG. 8B and WΔd ≦ D in FIG.
ty and the signal widths W ₁₁ , W ₁₂ , W
_21, W ₂₂ is W _11> W ₁₂ and W ₂₁ <W ₂₂ or W ₁₁ <W ₁₂
And W ₂₁ > W ₂₂ .

Therefore, one of the light receiving signals of the photoelectric sensors 1a and 1b is WΔc ≦ Dty or WΔd ≦ Dt
When the vehicle is interrupted at a signal interval satisfying y, it is detected that the two vehicles 5c and 5d have passed the photoelectric sensors 1a and 1b in a running state of catching up or overtaking.

At this time, if only WΔc ≦ Dty is satisfied, it is determined that the vehicle is in the catch-up running state of FIG.
If only Dty is satisfied, it is determined that the vehicle is in the overtaking traveling state shown in FIG. 7, and WΔc ≦ Dty and WΔd ≦ Dty, and W ₁₁ > W ₁₂ and W ₂₁ <W ₂₂ or W ₁₁ <W ₁₂ and W ₂₁ >
If W ₂₂ identifies that the overtaking traveling state of FIG.

When the catch-up is determined in FIG. 6 where WΔc ≦ Dty, the signal width W ₂ of the light receiving signal of the photoelectric sensor 1b is determined according to the ratio of the two signal widths W ₁₁ and W ₁₂ of the light receiving signal of the photoelectric sensor 1a. The two signal widths W ₂₁ and W shown in the following two equations (26)
Divide into ₂₂ .

[0135]

W ₂₁ [sec] = W ₂ · {W ₁₁ / (W ₁₁ + W ₁₂ )} W ₂₂ [sec] = W ₂ · {W ₁₂ / (W ₁₁ + W ₁₂ )}

Further, the time (t _2c ′ −tm) from the intermediate time tm to t _2C ′ of the signal width WΔc is regarded as one vehicle, and the signal delay time W ₀ of the light receiving signals of the photoelectric sensors 1a and 1b when viewed as one vehicle. [Sec].

Then, the signal widths W ₁₁ and W ₁₂ , and W ₁₂ and W ₂₂ are substituted for W ₁ and W ₂ in the equation (9), respectively, and the time (t _2C '−tm) is substituted for W ₀ in the equation. And two vehicles 5 from the same formula
The estimated vehicle lengths lc [m] and ld [m] of a and 5d are obtained.

Next, when overtaking is determined in FIG. 7 where WΔd ≦ Dty, the signal width W ₁ of the light receiving signal of the photoelectric sensor 1a is determined according to the ratio of the two signal widths W ₂₁ and W ₂₂ of the light receiving signal of the photoelectric sensor 1b. The two signal widths W ₁₁ , W
Divide into _twelve .

[0139]

W ₁₁ [sec] = W ₁ · {W ₂₁ / (W ₂₁ + w ₂₂ )} W ₁₂ [sec] = W ₁ · {W ₂₂ / (W ₂₁ + w ₂₂ )}

Further, the time (tn-t _1d ′) from the time t _1d ′ to the intermediate time tn of the signal width WΔd is determined by the photoelectric sensor 1.
It is assumed that the signal delay time W ₀ [sec] of the light receiving signals a and 1b.

The estimated vehicle lengths lc [m] and ld of the two vehicles 5c and 5d are obtained from the equation (9) in the same manner as in the case of FIG.
[M] is obtained.

Next, when the overtaking is determined in FIG. 8, the two signal widths W ₁₁ and W ₂₂ and the two signal widths W ₁₂ and W ₂₁ are converted into the two signal widths W ₁ of the equation (9).
And W ₂ , and an intermediate time t between the signal widths WΔc and WΔd.
The time difference (tn−tm) between m and tn is calculated as the time W _{0 in} the equation (9).
From the same formula, the estimated vehicle length lc [m] of the vehicles 5c and 5d is given by
Find ld [m].

The estimated vehicle lengths lc and ld are set to l ₁ and l _{2, respectively.}
In each case, a combination of large and small vehicles 5c and 5d is specified based on the determination conditions (a), (b) and (c), and the type of the vehicle is identified.

[0144] Incidentally, the arithmetic processing unit 9 specifically operates as shown in the flowchart of FIG. 9, for example, a photoelectric sensor 1a, a light reception signal 1b collected in step Q _1, above the step Q ₂ to Q ₅ in the the manner determined vehicle running state, based on the determination, performs the vehicle type identification in each traveling state in step Q ₆ to Q _9.

The large and small reference vehicle lengths are 1 each.
Only one may be set, or three or more may be set for each. It is needless to say that the present invention can be applied to the measurement of traffic volume on various two-lane roads.

[0146]

The present invention has the following effects. First, in the case of claim 1, it is considered that the light receiving signals of the photoelectric sensors 1a and 1b have changed in level when one vehicle travels alone, and the signal widths W ₁ and W ₂ of the light receiving signals of the _two photoelectric sensors 1a and 1b are determined. The estimated vehicle length 1 is obtained from the time W ₀ corresponding to the difference in the level change timing (the time difference between the vehicle passages), and the vehicle speed (instantaneous vehicle speed) V when this vehicle passes through the measurement points P ₁ and P _{2. 1,} the calculated V _2, if alone traveling, W ₁ -W V _2> it is not obtained there become V _U during acceleration state of ₂ ≧ [delta], V ₁ during deceleration state of the W ₂ -W ₁ ≧ δ >
Since V _D cannot be obtained, W ₁ −W ₂ ≧ δ
If V ₂ > V _U or W ₂ −W ₁ ≧ δ and V ₁ > V _D , it is regarded that the vehicle is running in two lanes, and the parallel running state is detected.

When the parallel running state is detected, the length of the parallel running vehicle at each of the _first and _second measurement points P ₁ and P ₂ ,
By comparing with a small reference vehicle length, two large and small vehicles running in parallel are identified.

Therefore, it is possible to detect the parallel running state of a two-lane vehicle, which was impossible in the past, and to discriminate the two large and small vehicle types.

In the case of the second aspect, the two photoelectric sensors 1
When either one of the light receiving signals a and 1b is intermittent at short intervals, a running state of catch-up or overtaking is detected, and the light receiving signal based on the detection of the parallel running state of the other photoelectric sensor is detected by this detection. The signal is divided into two signal widths by the ratio of the two signal widths generated by the intermittent light receiving signals of the photoelectric sensor.

Then, one of the two signal widths based on the passage of one vehicle is defined as two signal widths based on the passage of one vehicle, and the other two signal widths are defined as two signal widths based on the passage of the other vehicle. The vehicle length is calculated based on the two signal widths in the same manner as in the single traveling state.

Then, by comparing the calculated vehicle lengths with the large and small reference vehicle lengths, the large and small vehicle types of the two vehicles traveling in the overtaking / overtaking traveling state were determined.
It is possible to detect a catching / overtaking traveling state of a two-lane vehicle, which has been impossible in the past, and identify the two large and small vehicle types.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of one embodiment of the present invention.

FIG. 2 is an explanatory view of the arrangement of the photoelectric sensor of FIG. 1;

FIGS. 3 (a), (b), and (c) are explanatory diagrams of traveling of the vehicle in the case of independent traveling, and waveform diagrams of light receiving signals at first and second measurement points.

4 (a), (b), and (c) are explanatory diagrams of vehicle running in the case of catch-up, and waveform diagrams of light receiving signals at first and second measurement points.

FIG. 5 is a diagram illustrating a relationship between a traveling distance and a vehicle speed during acceleration / deceleration traveling.

6 (a), (b), and (c) are explanatory diagrams of vehicle running when catching up, and a waveform diagram of a light receiving signal at first and second measurement points.

FIGS. 7A, 7B, and 7C are explanatory diagrams of vehicle running in a first case of overtaking, and waveform diagrams of light receiving signals at first and second measurement points.

FIGS. 8A, 8B, and 8C are explanatory diagrams of vehicle running in a second case of overtaking, and waveform diagrams of light receiving signals at first and second measurement points.

FIG. 9 is a flowchart for explaining the operation of the arithmetic processing unit in FIG. 1;

[Explanation of symbols]

1a, 1b photoelectric sensor 2 roadway 2a, 2b lane 6 measurement computation unit P _1, P ₂ first, second measurement point

Claims (2)

[Claims] 1. A traveling vehicle identification device which performs non-contact measurement of a traveling vehicle on a two-lane road by performing non-contact measurement, and discriminates between a large vehicle and a small vehicle in a traveling direction separated by a predetermined distance longer than a predicted maximum vehicle length of the road. A photoelectric sensor which is provided at a first measurement point and changes a level of a light reception signal due to shading based on vehicle passage; and a measurement calculation device which processes light reception signals of the both photoelectric sensors. the means for detecting and monitoring the level change of the received light signals of both photoelectric sensors, the predetermined distance L, wherein W ₀ a time corresponding to the time difference of the vehicle passing the two photoelectric sensors, vehicle passes the two photoelectric sensors Means for calculating the estimated vehicle length l of the traveling vehicle from the following equation ( ₁₎ , where the signal widths of time are W ₁ and W _2, and the two measurements are made based on the estimated vehicle length l and the signal widths W ₁ and W _2. Calculate vehicle speed V ₁ , V ₂ at point And the two vehicle speeds V ₁ ,
Means for calculating the average of the V ₂ as average vehicle _{speed, W 1 -W 2 ≧ δ (} δ is a positive constant) and the second measurement point based on the average vehicle speed when considered alone accelerated running at an acceleration determination made in The upper limit vehicle speed V _U at W ₂ -W ₁ ≧
The upper limit vehicle speed V at the first measurement point based on the average vehicle speed when the vehicle is considered to be solely decelerated when the deceleration is determined to be δ.
Means for calculating a _D, W ₁ -W ₂ ≧ _δ cutlet V _2> V _U or W wherein both measuring the two-lane vehicle is running parallel state when the ₂ -W ₁ ≧ [delta] cutlet V _1> V _D Means for detecting that the vehicle has passed a point, and calculating the parallel running length at the two measurement points based on the signal widths W ₁ and W ₂ and the vehicle speeds V ₁ and V ₂ when the parallel running state is detected, Means for identifying large and small vehicle types of two vehicles running in parallel by comparing the length of the two parallel running vehicles with a large and small reference vehicle length. 1 = L · 2 / W ₀ / (1 / W ₁ + 1 / W ₂ ) 2. A traveling vehicle identification device that performs non-contact measurement of traveling vehicles on a two-lane road by performing non-contact measurement, wherein the first and second traveling directions separated by a predetermined distance longer than the predicted maximum vehicle length of the road. 1, a photoelectric sensor provided at a second measurement point, the level of a received light signal being changed by shading or reflection based on vehicle passage, and a measurement operation device for processing the received light signals of both photoelectric sensors; Means for monitoring and detecting a change in the level of the light reception signals of the two photoelectric sensors; and when the light reception signals of at least one of the two photoelectric sensors are intermittent at a signal interval of a predetermined time difference or less.
Means for detecting that the vehicle in the lane has passed the two measurement points in a running state of catching / overtaking; and detecting the intermittent running of one of the photoelectric sensors when detecting the running state of catching / overtaking. Done 2
The other light receiving signals of the two photoelectric sensors are divided into two signal widths corresponding to the vehicle transit time according to the ratio of the signal widths. Means for calculating the vehicle length of each of the two lanes based on the time difference between the vehicles passing by the photoelectric sensor, and running in catch-up / overtaking conditions by comparing the vehicle lengths of the two vehicles with the large and small reference vehicle lengths Means for identifying large and small vehicle types of two vehicles.