JPS6325400B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in road traffic control devices.

One method for accurately controlling traffic flow on wide-area road networks is a route guidance system that communicates between the ground and vehicles and guides vehicles along the optimal route to their destination. . This is roughly as follows.

A plurality of major points are determined in advance within the road network within the control target range. At each of these points,
Assign a unique point code. Roadside processing equipment is installed at each point, all of which can exchange data with a central unit at the control center. On the other hand, a vehicle to be controlled is equipped with an on-vehicle device that can communicate with the road processing device.

When such a vehicle passes a certain point, the on-vehicle device transmits the point code of the vehicle's destination to the roadside processing device, and in response, the onboard device sends the point code of the destination of the vehicle from the roadside processing device to the destination ( Generally, it receives route guidance information along the shortest time route). This route guidance information is, for example, a route instruction such as whether to go straight through the intersection at the point, or whether to turn left or right. Since such route instructions are given each time the vehicle passes through each point, if the driver drives the vehicle in accordance with the directions, the vehicle can travel along the route in the shortest time to the destination.

In such a route guidance system, the shortest time route is determined as follows. First, the central device collects the travel time (hereinafter referred to as travel time) for each of all road sections (between two predetermined major points) in the road network.
For this purpose, for example, the travel time measurement method already proposed by the applicant (Japanese Patent Laid-Open No. 55-135998
No. 58-40797) can be used.

Specifically, when the vehicle passes a first point on the road, the ground device at that point transmits a point code uniquely assigned to that point and a trigger signal, and the vehicle receives the trigger signal. The point code is written in a register mounted on the vehicle, and a counter is activated by the trigger signal to start counting reference pulses, and when the vehicle passes a second point, the point code stored in the register is code and the current contents of the counter.
The ground device at the second point calculates the time required for the vehicle to travel between the points (travel time) from the received point code and the contents of the counter. The travel time data for each section collected in this way is sent to the center for use. Additionally, the central unit utilizes the collected travel times to determine each shortest time path from one point to every other point. For this purpose, it is possible to use, for example, an apparatus for calculating the shortest time route, which has also been proposed by the applicant (see Japanese Patent Application Laid-Open No. 54-121042 (Japanese Patent Publication No. 58-40796)).

This device includes a point module provided corresponding to each point of a road network, and a trip control device for controlling the module, and each point module has a register for storing a point code; An arc module is provided corresponding to an arc terminating at the point, and the arc module has a register that stores a starting point code of the arc, and a register that stores the starting point code and the starting point code. It has a determining device for detecting and a register in which the arc cost is set, and based on the output of the determining device, the contents of each arc cost register are counted down with a predetermined synchronization pulse, and the point where the contents first reach 0 is determined. The code of the module is configured to be given to each point module as a new starting point. Here, the above-mentioned road section is associated with the arc, and the above-mentioned travel time data is given as the arc cost. As a result, for example, considering a road network with n points, a total of (n-1) shortest time routes are determined. Such shortest time routes are determined for all points within the road network. Therefore, in the case of the above example, the n×(n-1) shortest time route is determined.

Please note that traffic conditions within the road network change from moment to moment.
The travel time for each road section changes accordingly.
Therefore, the shortest route from one point to another is not always the same. Therefore, the shortest route information is also updated, for example, every 15 minutes, 30 minutes, or 60 minutes, depending on newly collected travel times.

The information on the shortest route from a certain point to all other points thus determined is sent from the central device to the road processing device at the certain point and stored in its memory. In this way, the reason for pre-calculating the shortest route as mentioned above for all points and having it in the road processing device at the corresponding point is that the on-vehicle device and the road processing device are generally used when a vehicle passes a point. This is because the time during which communication is possible with the vehicle is relatively short, and route information can be given to the vehicle during that short time.

Now, when a vehicle approaches a certain point and gives the point code of that destination to the road processing device, the road processing device uses that destination point code as an index to search its own memory and travel from that point to the destination. The shortest time path can be found. By knowing this shortest route, it is possible to instruct the vehicle on the course it should take at the intersection at that point.

As is clear from the above, in the above system, the central device calculates the shortest route for all combinations with a certain point in the road network as the starting point and another point as the destination. However, as the scale of the road network increases, the time required to calculate the shortest route increases, which consumes most of the operating time of the central unit, making it difficult to perform control that responds quickly to changes in traffic conditions. It was hot.

An object of the present invention is to provide a road traffic control device that can reduce the burden on a central device and can immediately respond to changes in traffic conditions.

The present invention is characterized by road equipment that is installed at predetermined points on a road network and that gives a point code uniquely assigned to the point to vehicles passing through those points; On the other hand,
a central device that transmits connection relationship data of each point constituting a road network and travel time data of each road section in the road network; and an on-vehicle device mounted on the vehicle; a first register for registering a point code of a vehicle's destination; a second register for storing a point code given from the roadside equipment; a memory for storing data transmitted from the central device; from the point stored in the second register based on the first
a device for calculating the shortest route to the point stored in the second register; and a device for displaying route instructions at the point stored in the second register based on the calculation results of the calculation device.

This will be explained in detail below using figures.

FIG. 1 schematically shows the overall configuration of an embodiment of the present invention. In the figure, 1 is a road;
Reference numeral 2 indicates a vehicle traveling there, 3 indicates a roadside device installed at point A, and 4 indicates a central device at a control center.
The vehicle 2 and the central device 4 are provided with antennas 5 and 6, respectively, for mutual communication.

As will be described in detail later, the functions that the on-road device 3 should have are determined depending on how the functions are shared with the central device 4. In this embodiment, at least a vehicle 2 passing through point A
It has the function of transmitting a point code uniquely assigned to that point. Note that, if only the function of providing the point code of the point in question to the vehicle 2 is concerned, no special device is required at the point in question. For example, a well-known barcode can be used. That is, a barcode corresponding to the code of the point may be displayed on the road surface.

The central device 4 transmits at least two pieces of data to the vehicle 2 via the antenna 6. One of the two pieces of data is connection relationship data of points that make up the road network, and the other is travel time data for each road section. The former data consists of a point code for each point and point codes for the end points of all road sections starting from the point.

In addition, the latter data is from the previously mentioned JP-A-55-
The central device 4 collects the travel time of each road section measured by a method such as No. 135998 (Japanese Patent Publication No. 58-40797), and transmits it to the vehicle 2. The above Japanese Patent Publication No. 55-135998 (Special Publication No. 58-40797)
Although the travel time measurement method described in No. 1) directly measures the time required to travel between two points, the travel time data described above can also be obtained by other methods.

For example, the occupancy time used to determine an index such as the degree of congestion or congestion of a certain road section is obtained, and the travel time of the road section is estimated from that value. This occupancy time is measured as follows. Vehicle detectors are installed near the end of the road section. This vehicle detector is a well-known device that uses electromagnetic waves or ultrasonic waves.
Sampling detection of vehicles passing through a detection point is performed at a certain period (for example, 20 to 50 milliseconds), and when a vehicle is detected, a pulse with a certain time width is generated.
This pulse is counted every predetermined measurement time. The total pulse width time of pulses existing within each measurement time, that is, the product of the pulse count value within the measurement time and the pulse width time is the occupied time. The degree of congestion is estimated using the occupancy time determined in this manner or the ratio of the occupancy time to the above-mentioned measured time. Then, the travel time is determined by determining how long the travel time would be if the road section was congested to this extent.

The two data described above are essential data when searching for the shortest route from one point to another. However, in an actual road network, traffic restrictions may be imposed on a certain road section due to accidents, construction, demonstrations, or other reasons. In such a case, when calculating the shortest time route, it is necessary to exclude that road section from the road sections to be searched in order to make a detour. Therefore, in addition to the above two data, the data sent from the central device 4 to the vehicle 2 includes:
It is even more desirable to include traffic regulation data.
Such traffic regulation data can be registered in the central device 4 by a report from an accident witness to the control center or a notification from the police or the like.

Next, the vehicle 2 receives the point code from the roadside device 3 and data from the central device 4 as described above.
The in-vehicle device on the side will be explained.

FIG. 2 shows the configuration of an on-vehicle device according to an embodiment of the present invention. In the figure, 5 is an antenna attached to the vehicle 2 shown in FIG.
Reference numeral 7 indicates a receiver, and reference numeral 8 indicates a buffer memory, which stores data received from the central unit 4 by the receiver 7. 9 is an input device for the driver to register a destination point code in advance; 10 is a destination point code register that stores the point code input from the input device 9; Reference numeral 11 denotes a point code detector, which receives a signal from the on-road device 3 when passing a point, and detects the point code of the point from the received signal. It should be noted that, as mentioned above, when the point code is given as a barcode, it goes without saying that the point code detector 11 has the function of reading such a barcode. Reference numeral 12 denotes a detection point code register in which a point code detected by the point code detector 11 is stored, and its contents are rewritten each time a new point is passed.

13 shows a shortest time route calculation device, and for this purpose, the above-mentioned Japanese Patent Application No. 53-27772
40796) can be used. Then, this calculation device 13 uses various data regarding the road network stored in the buffer memory 8 to
The shortest time route from the point of the code stored in the register 12 (that is, it indicates the current position of the vehicle 2 and serves as the starting point when determining the shortest time route) to the destination point stored in the register 10 It is used to calculate. Reference numeral 14 denotes an output buffer memory that stores the calculation results of the shortest route calculation device 13.

15 is a decoder which converts the point code stored in the register 12 into the name of a selected point, such as an intersection, or converts the point code stored in the register 12 into the name of an intersection, etc. The purpose is to find the shape of the road. Reference numeral 16 denotes a display image creation device that creates a display screen by combining the various information converted by the decoder 15 and the contents stored in the output buffer memory. 17 is a display device.

An example of the display on the display device 17 is shown in FIG. As shown in the figure, the display screen consists of a portion 18 that displays the location name, portions 19 to 25 that display the road shape of the location, and an indicator light 26 that indicates that the user has arrived at the destination. The location name display section 18 displays the location name obtained by decoding the code stored in the register 12 by the decoder 15.
Further, the road shape display sections 19 to 25 are normally invisible, and only those based on the data read from the buffer memory 8 are visibly displayed.

For example, if the next point to approach (the name of the point is displayed on the display section 18) is a crossroads, the display sections 20, 22, and 24 are visibly displayed. Among those displayed items, those designated by the contents of the output buffer memory 14 may be displayed in a different color or have a higher brightness than others, or may be visually distinguished from other items displayed. Displayed by. In the illustrated example, the point A that the driver is about to approach is a crossroads, and indicates that the driver should turn right at the point A.

Next, the operation of the above-mentioned device will be explained. First, prior to departure, the driver registers the point code of the destination point in the register 10 using the input device 9.

Further, when the on-vehicle device starts driving, the receiver 7 receives the at least two pieces of data transmitted from the central device 4 and stores it in the buffer memory 8.

When vehicle 2 starts traveling and approaches point A,
The point code detector 11 receives the point code transmitted from the on-road device 3 and stores it in the register 12. The calculation device 13 reads road network data from the buffer memory 8 and determines the shortest route from the point stored in the register 12 to the point stored in the register 10. The result is stored in the output buffer memory 14. The display image creation device 16 synthesizes a display screen using the output from the decoder 15 and the information read from the output buffer memory 14, and displays it on the display device 17.

When the vehicle 2 continues to drive according to the route instructions created based on the route guidance information received at point A and approaches the next point (hereinafter referred to as point B, not shown), the on-vehicle device repeats the same operations as described above to create route instructions at point B.
However, in this case, while the vehicle 2 is traveling between points A and B, the contents of the buffer memory 8 may be updated. Therefore, the calculation of the shortest time route performed after receiving the point code from the roadside device at point B will be based on different traffic situation data than at point A, and the result will also be different. May. However, it can be said that the shortest route determined at point B was determined based on more recent traffic situation data.

As described above, according to the present invention, the shortest time route calculation process is executed not in the central unit as in the past, but in each individual vehicle, so that the burden on the central unit is significantly reduced. As a result, control that can immediately respond to changes in traffic conditions becomes possible, regardless of the size of the road network or the number of vehicles to be controlled.

Furthermore, by transmitting connection relationship data of points on the road network to the vehicle, route guidance on any road network can be received using the same in-vehicle device. For route guidance systems on two adjacent road networks, problems caused by interference can be prevented by making the transmission frequencies from the central device different and allowing the vehicles to switch and synchronize accordingly.

Furthermore, if the roadside equipment used to give point codes to vehicles is installed well before the intersection selected as the point, there will be enough time for the on-vehicle device to calculate the shortest route. can be taken. This makes it possible to create more detailed route guidance information than the conventional method and provide it to the driver.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is a diagram showing an example of the configuration of an in-vehicle device, and FIG. 3 is a diagram showing an example of a display on a display device. Explanation of main symbols, 3; Roadside device, 4; Central device, 7; Receiver, 8; Buffer memory, 9; Input device, 10; Destination point code register, 11; Point code detector, 12; Detection point code register , 13; shortest time path calculation device; 14; output buffer memory; 15; decoder; 16; display image creation device; 17; display device.

Claims (1)

[Claims] 1. Roadside equipment installed at predetermined points on a road network and providing point codes uniquely assigned to those points to vehicles passing through those points;
The vehicle includes a central device that transmits connection relationship data of each point constituting a road network and travel time data of each road section to the vehicle, and an on-vehicle device mounted on the vehicle, and the on-vehicle device includes: a first register for registering a point code of a vehicle's destination; a second register for storing a point code given from the roadside equipment; a memory for storing data transmitted from the central device; a device for calculating the shortest time route from a point stored in the second register to a point stored in the first register based on the calculation result of the calculation device; A road traffic control device comprising: a device for instructing a course that the vehicle passing through a point should take;