JP2003085687A - Device for estimating time required for traveling between intersections - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately find the time required for traveling between intersections while taking such cases as waiting for traffic light and queuing into consideration by adopting a method of simulation. SOLUTION: Optical beacons B1 and B2 are respectively installed at a spot near the outflow part of an upstream intersection X1 and the spot near the outflow part of a downstream intersection X2, information of the passing time of vehicles passing through the optical beacons B1 and B2 is gathered and history information of a traffic light color of the downstream intersection is stored. On the basis of the time for which the passing time (a) of the vehicle from a stop line of the downstream intersection to the outflow part of the downstream intersection is subtracted from the passing time between both the spots of the vehicle specified as an identical vehicle, and by taking the history of the traffic light color of the downstream intersection and the number of the vehicles waiting for the traffic light before the downstream intersection into consideration, the traveling required time T from the spot near the outflow part of the upstream intersection to the stop line of the downstream intersection in the case of assuming that there is no need for waiting the signal traffic light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for estimating the required travel time between intersections. The travel time required between the intersections thus obtained is used for the control for optimizing the traffic signal parameters by predicting the traffic flow reaching from the upstream intersection to the downstream intersection.

[0002]

2. Description of the Related Art Vehicle detectors such as optical beacons are sometimes installed at intersections. This vehicle detector not only senses a passing vehicle, but also has a bidirectional communication function for exchanging information including vehicle identification information with an in-vehicle communication device mounted on the vehicle. With this two-way communication function,
Since the vehicle traveling between two intersections can be identified, the required traveling time between the intersections of the vehicles can be determined.

[0003]

However, since the vehicle detector is usually installed near the outflow portion of the intersection, the travel time required from the outflow portion of the upstream intersection to the outflow portion of the downstream intersection is Although it can be determined, it is not possible to directly determine the travel time T from the outflow portion of the upstream intersection to the stop line of the downstream intersection, which is the data actually required for controlling the traffic signal parameters.

This is because the vehicle may wait for a signal at a stop line at a downstream intersection, and this signal waiting time needs to be taken into consideration. Further, when the traffic volume is large, the number of people waiting in line for waiting for a signal also increases, so it is necessary to consider this line waiting time. Therefore, the present invention aims to realize an inter-intersection travel time estimation device capable of accurately obtaining the inter-intersection travel time in consideration of the case of waiting for a signal or waiting in line by adopting a simulation method. To aim.

[0005]

According to the present invention, there is provided an apparatus for estimating travel time between intersections, comprising a vehicle detector installed at a point near an outflow section of an upstream intersection and a vehicle detector installed at a point near an outflow section of a downstream intersection. Transit time collection means for collecting information on the transit time of the vehicle that has passed through the detector; signal light color history storage means for storing history information on the signal light color of the downstream intersection;
Vehicle identifying means for identifying the identity of vehicles passing through each of the points, and the outflow portion of the downstream intersection from the stop line of the downstream intersection from the passage time between the two points of the vehicles identified as the same vehicle by the vehicle identifying means. From the point near the outflow section of the upstream intersection, based on the time taken by subtracting the passage time a of the vehicle up to, and by considering the history of the signal light color at the downstream intersection and the number of signal waiting vehicles before the downstream intersection. A travel-required time estimating means for estimating a travel-required time T until reaching the stop line at the downstream intersection when there is no waiting.

The vehicle detector may be any one capable of detecting an individual vehicle such as an optical beacon, an ultrasonic vehicle detector, and a roadside camera. The vehicle identification means may be any one that identifies a vehicle by communicating with an in-vehicle device by a bidirectional optical beacon or the like, or one that reads a vehicle number plate like a camera. The passing time a of the vehicle from the stop line at the downstream intersection to the outflow portion at the downstream intersection is
It is a very small value compared with the transit time between intersections. Therefore, it may be set to approximately 0 (claim 4).

The above-mentioned "considering the history of signal light colors at downstream intersections and the number of signal waiting vehicles before the downstream intersection" specifically means the number of signal waiting vehicles at the downstream intersection when the signal light color at the downstream intersection is red. The number of vehicles waiting for a signal at a downstream intersection is decreased one by one when the number of vehicles at each downstream intersection is increased and the signal light color at the downstream intersection is blue (claim 2). Further, even when the signal light color of the downstream intersection is blue, when the number of signal waiting vehicles at the downstream intersection is not 0, the number of signal waiting vehicles at the downstream intersection may be increased every time the vehicle enters the downstream intersection ( Claim 3).

According to the configuration of the travel time estimation device between intersections, there is no signal waiting from the point near the outflow portion of the upstream intersection based on the passage time of the same vehicle from the upstream intersection to the stop line of the downstream intersection. In this case, the travel time T required to reach the stop line at the downstream intersection is estimated. In this case, the history of signal light colors at the downstream intersection and the number of signal waiting vehicles before the downstream intersection will be considered. That is, when the traffic light color of the downstream intersection is red, the vehicle cannot pass through the downstream intersection, and the number of vehicles waiting for the signal is increased each time the vehicle enters the downstream intersection. When the signal light color of the downstream intersection is blue, if there is a signal waiting for the downstream intersection, the number of vehicles is decreased by one every predetermined time. Even if the signal light color of the downstream intersection is blue, if there is a signal waiting vehicle number at the downstream intersection, the signal waiting vehicle number at the downstream intersection is increased each time the vehicle enters the downstream intersection.

By adopting the above simulation method, even at an intersection having a signal, the time required for traveling from the point near the outflow portion of the upstream intersection to the stop line of the downstream intersection when there is no signal waiting. It is possible to accurately estimate T. Further, even when there is a large amount of traffic and there is a signal queue, it is possible to accurately estimate the travel time T required to reach the stop line at the downstream intersection when there is no signal waiting.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a left-hand road map for use in explaining the present invention. An optical beacon B1 is installed near the outflow part of the upstream intersection X1,
An optical beacon B2 is installed near the outflow portion of the downstream intersection X2. Optical beacons are installed at many intersections, but since it is assumed here that the travel time between the intersections X1 and X2 is determined, the optical beacons B1 and B2 installed at the intersections X1 and X2 are assumed. Only illustrated.

FIG. 2 is a schematic functional block diagram of the apparatus for estimating the required traveling time between intersections. The optical beacon installed at each intersection is connected to the subordinate computer 11 in the relevant jurisdiction. The subordinate computer 11 receives a vehicle detection signal from the optical beacon each time the vehicle passes. Further, it receives from the optical beacon the data of the identification number of the passing vehicle (limited to the vehicle equipped with the in-vehicle communication device). In addition, a traffic signal within the relevant jurisdiction is connected to the lower computer 12. The lower computer 12 stores history data of signal color changes of traffic signals.

The above two lower computers 11, 12
Are connected to a central signal control computer 10.
The central signal control computer 10 is a low-order computer 1
Based on the passing vehicle data obtained from Nos. 1 and 12 and the signal history data, the time required for the vehicle to travel from the outlet of the upstream intersection X1 to the stop line of the downstream intersection X2 when there is no signal waiting Estimate T. The lower computers 11 and 12 and the central signal control computer 10 are composed of a central processing unit (CPU), a storage device (memory),
Since this is a well-known device equipped with an input / output device, detailed description of the configuration is omitted here. The procedure for estimating the required traveling time T of the vehicle described below is executed by a computer program stored in the memory.

The process of estimating the required traveling time T of the vehicle will be described below with reference to flowcharts (FIGS. 3 to 5).
This process is a process performed off-line based on the data of passing vehicles (passing time data and data of the identification number of the vehicle equipped with the in-vehicle communication device) accumulated in the past. The time variable in the process is represented by t. Referring to FIG. 3, first, ΔT is set to 0 (step S1). The required traveling time T of the vehicle is expressed as T = T1 + ΔT (step S2).
T1 is a fixed value and ΔT is a variable value. "Number of signals waiting"
Is set to 0 (step S3). The initial evaluation value is set to 0 (step S4).

Next, referring to FIG. 4, the signal color of the downstream intersection X2 at time t is determined (step S5). If it is a green signal, it is determined whether or not the "number of signals waiting" is 0 (step S6). If it is 0, it is determined whether or not there is a vehicle that has passed the upstream optical beacon B1 at time t-T (step S7). . If there is a vehicle passing the downstream optical beacon B2 near time t + a, a vehicle passing the upstream optical beacon B1 at the time t-T or a leading vehicle departing from the signal waiting at the time t. It is checked whether there is any (step S8). Here, the symbol a indicates that the vehicle is the downstream intersection X2.
It represents the time from exiting the stop line to passing through the downstream optical beacon B2, and is considered as a constant for convenience. Whether or not they are the same vehicle is determined by whether or not the identification numbers received from the vehicle-mounted communication device are the same. Therefore, even if the same vehicle is not equipped with the in-vehicle communication device, it cannot be judged on the ground side. However, if the identification numbers are different, they are not treated as the same vehicle. That is, the same vehicle as used herein is determined between vehicles that are equipped with an in-vehicle communication device and have uplinked to an optical beacon. The meaning of “near” at time t + a is determined by whether or not the downstream optical beacon B2 has been passed within a certain time before and after the time t + a. If the "constant time" is too small, the probability of finding the same vehicle is reduced, and if it is too large, the search takes time. Therefore, it is necessary to set an appropriate value through simulation or the like.

If there is the same vehicle, the time when the vehicle actually passed the downstream optical beacon B2 is referred to and
The difference from time t + a is obtained (step S9). And
The square of this difference is added to the evaluation value (step S1
0). The above is the process of evaluating the traveling time T from the upstream optical beacon B1 to the stop line of the intersection of the vehicle that has passed the upstream optical beacon B1 and passed the downstream optical beacon B2 without waiting for a signal at the intersection.

In step S5, the signal color of the downstream intersection X2 at time t is determined, and if it is a red signal, it is determined whether or not there is a vehicle that has passed the upstream optical beacon B1 at time t-T (step S11). . If there is, the number of signal waiting units is incremented by 1 (step S12). As long as there are red traffic lights, the number of traffic lights waiting will increase. When the signal turns green, YES is determined in step S5, and the process proceeds to step S6. If YES in step S6, the processes in step S7 and subsequent steps described above are performed. If NO in step S6, the processes in step S13 and subsequent steps, which will be described later, are performed.

Even if the signal color of the downstream intersection X2 is a green signal, if there is a vehicle waiting at the traffic light, the vehicle coming from behind may not always pass nonstop. In this case, it is determined in step S6 that there are signal waiting units,
It is determined whether or not there is a vehicle that has passed the upstream optical beacon B1 at time t-T (step S13). If any,
The number of signal waiting units is incremented by 1 (step S14). And
It is determined whether the time t is the timing when the leading vehicle departs (step S15). When there is a leading vehicle before, this timing is determined by whether or not a predetermined time has elapsed since the preceding leading vehicle left. The “predetermined time” means a time when vehicles waiting for a traffic light leave the green light one by one, and is a constant here.

If it is the timing when the leading vehicle departs,
Subtract one from the number of signals waiting (step S16), and proceed to step S8. Since the processing from step S8 to step S10 is as described above, the description will be omitted.
As described above, a vehicle that has passed the upstream optical beacon B1 and passed the downstream optical beacon B2 without waiting for a signal at an intersection, and the downstream optical beacon B after waiting for a signal at an intersection
It was possible to evaluate the travel time T of the vehicle that passed 2 from the upstream optical beacon B1 to the stop line at the intersection.

In FIG. 5, it is determined whether or not the time variable t has been processed at all times (step S1).
7). If all the time zones have not been processed, t is set to t + 1 (step S18), the process returns to the entrance of step S5, and the process is repeated. Next, it is determined whether or not the entire range of ΔT has been processed (step S19). If processing has not been completed for all ranges, change ΔT (step S2
0), return to the entrance of step S2, and repeat the process.
In this way, the evaluation value is obtained each time ΔT is changed. That is, the evaluation value as a function of ΔT is obtained.

In step S21, ΔT that minimizes the evaluation value is selected and T = T1 + ΔT is obtained. This T is the maximum likelihood value (a plausible value) that represents the time it takes for the vehicle to travel to the stop line at the intersection after passing the upstream light beacon B1. Although the embodiment of the invention has been described above, the embodiment of the invention is not limited to the above embodiment. For example, the travel time T from the point near the outflow portion of the upstream intersection X1 to the stop line of the downstream intersection X2 when there is no signal waiting described with reference to FIGS. 3 to 5 is set to T1 + ΔT. The method of obtaining the update amount ΔT that minimizes the difference from the transit time to the downstream optical beacon is only one solution for obtaining the travel required time T with a small error, and other methods besides this solution are also available. It is also possible to adopt the maximum likelihood estimation method. Besides, various changes can be made within the scope of the present invention.

[0021]

As described above, the apparatus for estimating the required travel time between intersections according to the present invention is suitable for the control for optimizing the traffic signal parameters by predicting the traffic flow reaching from the upstream intersection to the downstream intersection. It is possible to provide data on the travel time T.

[Brief description of drawings]

FIG. 1 is a left-hand road map for use in explaining the present invention.

FIG. 2 is a schematic functional block diagram of an intersection required travel time estimation device.

FIG. 3 is a flowchart for explaining a process of estimating a travel required time T of the vehicle.

FIG. 4 is a flowchart for explaining a process of estimating a vehicle travel time T (continuation of FIG. 3).

FIG. 5 is a flow chart for explaining a process of estimating a required travel time T of the vehicle (continuation of FIG. 4).

[Explanation of symbols]

10 Central signal control computer 11,12 Lower computer B1 optical beacon B2 optical beacon X1 upstream intersection X2 downstream intersection

Claims (4)

[Claims] 1. A vehicle detector installed at a point near an outflow section of an upstream intersection and at a point near an outflow section of a downstream intersection, and a transit time at which information on a transit time of a vehicle passing through the vehicle detector is collected. Collection means, signal light color history storage means for storing history information of signal light colors at downstream intersections, vehicle identification means for identifying the identity of vehicles that have passed through the points, and vehicle identification means for identifying the same vehicle Based on the time obtained by subtracting the passage time a of the vehicle from the stop line of the downstream intersection to the outflow portion of the downstream intersection from the passage time between the two points of the vehicle, and before the history of the signal light color of the downstream intersection and before the downstream intersection. By considering the number of signals waiting in
Inter-intersection travel, comprising travel time estimation means for estimating a travel time T from a point near the outflow portion of the upstream crossing to a stop line of the downstream crossing when there is no signal waiting Time estimation device. 2. When the traffic light at the downstream intersection is red, the number of vehicles waiting for traffic at the downstream intersection increases each time a vehicle enters the downstream intersection, and when the traffic light at the downstream intersection is blue, the number of vehicles waiting for traffic at the downstream intersection. The inter-intersection travel time estimation device according to claim 1, wherein the number of vehicles decreases one by one every predetermined time. 3. Even if the signal light color of the downstream intersection is blue, when the number of signal waiting vehicles at the downstream intersection is not 0, the number of signal waiting vehicles at the downstream intersection increases every time a vehicle enters the downstream intersection. The travel time estimation device between intersections according to claim 2. 4. The travel time estimation device between intersections according to claim 1, wherein the passage time a is regarded as 0.