JP2002157672A - Route selection system of traffic flow simulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a route selection system of traffic flow simulation which can shorten the route determination processing time and total computation time for individual vehicles even when a network is large in scale. SOLUTION: The necessary costs of the shortest routes from respective starting places and respective branch points to a destination are prepared and the route from a current place to the destination is sequentially selected and determined to shorten the route determination processing time for the individual vehicles. In route change processing, a traffic information notification means object for deciding whether or not route information needs to be changed is separated from a vehicle object and only when the traffic information greatly varies, cost updating is performed by a cost table object to eliminate unnecessary route information variation, thereby shortening the total computation time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traffic flow simulation which reproduces a route from a departure point to a destination by reflecting the route in the traffic flow, and in particular, communicates traffic information to individual vehicles in a large-scale network. The present invention relates to a route selection method in a traffic flow simulation that can change and determine a route of a traffic flow micro simulator having a communication means.

[0002]

2. Description of the Related Art In the current traffic network, the effect of introducing measures can be quantitatively evaluated when changing or newly constructing roads and traffic facilities for the purpose of eliminating traffic congestion and facilitating traffic, and supporting planning. There is a need for a traffic flow simulation using a traffic flow simulator that can be used. here,
The traffic flow simulation is a simulation in which traffic regulation, vehicle routes, and the like are reflected in the traffic flow to reproduce the influence on the entire traffic. Such a traffic flow simulation includes a traffic flow macro simulation that treats traffic as an approximation of a continuous fluid and a traffic flow micro simulation that simulates the behavior of each vehicle and reproduces the traffic flow by stacking. It is roughly divided into two.

[0003]

However, the above-described conventional traffic flow simulation has the following problems. In other words, the traffic flow macro simulation treats traffic as a continuous fluid approximation, so the amount of calculation can be reduced, so that it is easy to put it to practical use even for large-scale networks. In practice, there is a problem in the simulation accuracy. On the other hand, the traffic flow micro-simulation simulates the behavior of each vehicle, so there is an advantage in modeling that makes it easy to express routes and express traffic regulations.However, the computational complexity is large, so if the network becomes large-scale, There is a problem that it is difficult to change the route of each vehicle.

[0004]

In order to achieve the above object, the present invention provides a traffic flow simulator having communication means for communicating traffic information to individual vehicles. Only the required cost of the shortest route from each branch point to the destination is stored, and the route from the departure point to the destination is sequentially selected when the vehicle is generated and when the driver obtains the traffic information. It is characterized by making decisions. According to a second aspect of the present invention, in the first aspect of the present invention, a cost table object having a shortest route search process that requires a large amount of calculation and takes a long time among all the traffic flow simulators and determines whether or not the route information needs to be changed. The traffic information notification means object to be moved is divided into a vehicle object for moving the vehicle so that the calculation time period can be changed for each processing, and a cost update request is sent to the cost table object only when traffic information changes significantly. It is characterized by passing.
According to a third aspect of the present invention, in the first or second aspect of the present invention, the shortest path is searched by the entire network excluding the entered link for each entry direction at each branch point, and the selected path is selected. Is not present, the cost value is specially set to “−∞”. Further, the invention described in claim 4 is the invention according to claim 1.
Any one of the inventions described in any one of (1) to (3) above, wherein the invention is directed to a vehicle whose traffic information has been obtained.

Accordingly, an object of the present invention is to solve the above-described problems of the conventional traffic flow simulator, and to reduce the route determination processing time and the total calculation time for each vehicle even when the network is enlarged. An object of the present invention is to provide a route selection method in a traffic flow simulation that can be shortened.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described in detail with reference to FIG. Here, first, route information in the traffic flow simulator will be briefly described. The route information in this traffic flow simulator can be roughly classified into the following two patterns. (As an example,
Suppose you go on a trip. A person who decides a route based on traffic information such as a map, TV, or radio before starting a trip and does not change the route during the trip. A person who changes the route determined before the start of the trip based on the traffic information during the trip. Next, considering traffic measures to provide traffic information to existing drivers, the means of providing traffic information can be provided by information media such as televisions and radios. VICS, etc., each of which has a wide area but depends on the sender's schedule. Also, only partial drivers will have access to that information. In the case of, although information cannot be obtained unless the user reaches the point, the information is accurate in real time, and all drivers passing therethrough access the information. In the case of, the beacon type is similar to the above,
The wide area broadcast type can be used as accurate information in a wide area and in real time. And the like.

In the present invention, the route selection pattern of the vehicle is defined as the following “five categories” based on each of these traffic measures. Those who decide the route based on the map at the time of departure and do not change thereafter. The route is determined based on the traffic information obtained at the time of departure,
Those who do not change thereafter. Or a person who changes the route determined according to traffic conditions (observable in the field of view) while traveling. Or a person who changes the route determined by the information at a specific point (variable display board, beacon). Or a person who changes the route while traveling on the route determined by referring to traffic information periodically. The means for solving the above problems will be described below as embodiments.

FIG. 1 shows a schematic flow of route determination processing in a traffic flow simulation according to the present invention. FIG. 2 shows a related form of each object related to the route determination in the traffic flow simulation according to the present invention. First, the definition of each object shown in FIG. 2 will be briefly described. In the present invention, the related form of each object related to the route determination in the traffic flow simulation includes a node object 1, a link object 2, a vehicle object 3, a cost table object 4, and a traffic information notification means object 5. a) Node object 1 (end point) This is an object that defines a road end and a branch point in a road network on a computer. It has a node No, an inflow link No, and an outflow link No. b) Link object 2 (road) An object that defines a line connecting nodes. Link No., distance, regulated speed information, average speed information in link, toll, start node No., end node No.,
And a pair link No. Here, if there is an “up line” and a “down line” on the road, the links are set as different links, and the link numbers of each other are set as pair link numbers. c) Vehicle object 3 This is an object representing each vehicle traveling on the road network. It has a route selection process and route information. Depending on the attributes of each vehicle, whether traffic information is used or not, a route change is made only on a specific link, or there is no constraint information. d) Cost table object 4 This object manages and stores the "shortest cost" required from each node to the destination node of the travel destination. e) Traffic information notification means object 5 The traffic congestion status of each link is monitored at regular intervals, and if the average speed information within the link becomes a certain value or more and becomes lower than the regulation speed information, it is determined that there is an information change and the route information of the vehicle object is changed. Is an object that requests a change (reroute) of

Hereinafter, the processing will be described in order (S1 to S13) with reference to the flowchart of FIG. 1. Timing Processing Determination (S1) Initial data creation is from the start of the simulation to creation of the network and creation of the cost table, and all other cases are movements of the vehicle.

[0010] 2. Creation of network (S2) The process of building a road network on a computer. Data is created so that the network configuration is aimed at node objects and link objects. Here, FIG. 3 shows an example of a target network configuration. In the example of FIG. 3, the node A is a source node and the node E is a destination node.

3. Creation of Cost Table (S3) The creation of the cost table is performed using a cost table object. The contents will be described below.
Information without considering traffic information (CA) in the cost table
And information (CB) to be considered, and each is determined as follows. Information not considering traffic information Starting from the inflow link entering each node, the shortest route to the destination node, which is the destination of travel, is searched in a state excluding the inflow link and the pair link from the network (see FIG. 4). The total cost up to the destination node is calculated and stored in the cost table.

Here, as a method of calculating the total cost, the total cost of all links passing from the departure link to the destination node, and the cost of each link (the cost of the link without considering traffic information) is as follows. It is calculated by the equation of “Equation 1”. However, the total cost when the route to the destination node is not obtained is “−∞”.

[0013]

CA = f (L, V, N) CA: link cost without considering traffic information L: link distance V: regulated speed information of link N: link toll

Various methods, such as the Dijkstra method, are generally known as a method of searching for the shortest path, and a node sequence to be the shortest path is determined by using these methods. Here, FIG. 4 shows an example of a node row that is the shortest path. That is, using the link AB as a departure link,
If the destination node is the destination node E, the shortest path is searched without the link AB and the link BA, and the node sequences B, C, and E are determined. Next, the link (B
The total sum of the costs of C, CE) is registered in the cost table, and this is performed for all inflow links.

Information Considering Traffic Information In the information not considering traffic information described above, the total cost when the formula for calculating the cost of each link is defined by the following “Formula 2” by the formula of “Formula 1” is also calculated. , And registers the calculation result in the cost table.

[0016]

CB = f (L, Va, N) CB: Cost of link considering traffic information Va: Average speed information in link of link Here, if there is no average speed information in link, regulated speed of link Use information.

4. Vehicle generation processing (S4) A vehicle object is sequentially generated on the computer for each of the predetermined numbers of O (source nodes) and D (destination nodes) generated, and vacancies are provided on the links flowing out of the source nodes on the road network. Register to the part. At this time, the presence / absence of use of traffic information is added to each vehicle object based on the occurrence distribution of vehicles using traffic information and vehicles not using traffic information.

5. Initial Route Process Determination (S5) For each vehicle object created by the vehicle generation process (S4), a process for determining a route to a destination node as an initial route is determined. Based on the use of traffic information, if there is, the vehicle goes to S7 (initial route determination process B) as a vehicle using traffic information, and if not, the following S6 (initial route determination process A) is taken as a vehicle not using traffic information. I do.

6. Initial Route Determination Process A (S6) An example of a vehicle that does not use traffic information will be described with reference to FIG. Here, it is registered in the link AC in the vehicle generation process, and this is set as the outgoing link. Next, the link to be advanced to next is determined by using the terminal node C of the currently existing link as a branch point. Here, when a plurality of links are candidates, the link is determined by the following logit model equation of “Expression 3” and “Expression 4”.

[0020]

(Equation 3) Here, Pi: establishment of selection of inflow link i i: inflow link No j: inflow link No group Ci: total cost from inflow link i to destination node α: sensitivity coefficient Cxy: cost CA on link xy (“ CAyz: total cost CA from node y to destination node z
(Determined from cost table)

[0021]

## EQU4 ## Ci = Cxy + CAyz

Next, all outgoing links other than the link AC and the paired link CA are searched for links (CB, CD, CE).
Get. That is, information is retrieved from the cost table shown in FIG. 5 with the above-mentioned link (CB, CD, CE) as the inflow link and with the node E as the destination node.
And calculate the probability of passing through each link. At this time, on the cost table, the value of the sum of CA is "-
If it is “∞”, the probability is “0” because there is no route to reach the node E. Then, a link to be passed next is determined based on the probability determined above. Thereafter, the link is followed in the traveling direction to the destination node to determine a route. The determined link sequence is stored in the vehicle object and used in the vehicle movement processing.

7. Initial Route Determination Process B (S7) In the case of a vehicle using traffic information, the above-mentioned 6. CA in
The same process is performed for the part using CB.

8. Vehicle Movement Process (S8) The vehicle movement process is performed by a generally known free running or following theoretical formula.

9. Route change processing determination (S9) If there is no traffic information use, it is determined that there is no line change. When there is traffic information use presence / absence, the following determination is made based on the information change report from the traffic information notification means object, and the process branches to the next process. If the link with the information change is different from the scheduled passage of the own vehicle, it is determined that there is no route change. When the link where the own vehicle exists and the link that passes next have the information change, the process S10 is executed as a traffic jam immediately before the own vehicle. In cases other than the above, when the attribute of the vehicle object is other than the specific link, the route is not changed. In addition to the above, it is determined that there is traffic congestion information on the traveling route, and the process S11 is performed.

10. Route Change Process A (S10) In a case where a route is changed according to the immediately preceding situation, a new route to the destination node is changed in process S6 in which only the above-described equation (4) is changed to the following, using the currently existing link as the originating link. decide.

[0027]

Where Cbxy: cost CB at link xy (calculated by equation 2) CAyz: total cost CA from node y to destination node z
(Determined from cost table)

11. Route Change Process B (S11) When a route is changed due to a change in information on a passing link, the same process as process S7 is performed using the currently existing link as the originating link and the latest cost CB.

12. All-vehicle movement process in network (S12) When the process for all vehicle objects is completed, the process returns to S1. Then, the process proceeds to the processing S12 before the end.

13. Target vehicle update (S13) A target vehicle is selected from unprocessed vehicle objects and set as a target vehicle.

The above processing is repeatedly performed according to a certain processing cycle until the end of the simulation. This allows
The movement of the vehicle on the computer can be reproduced including the vehicle traveling while changing the route depending on the situation during the simulation, and the simulation of the traffic flow can be performed more accurately.

[0032]

The present invention is as described above and according to the first aspect of the present invention, there is provided a traffic flow simulator having a communication means for transmitting traffic information to each vehicle individually. Only the required costs for the shortest route to the route are stored, and when the vehicle is generated and when the driver obtains traffic information, the route from the departure point to the destination is sequentially selected and determined. Thus, there is an effect that the route determination processing time for each vehicle can be reduced. According to a second aspect of the present invention, in the first aspect of the present invention, a cost table object having a shortest route search process and a traffic information notifying means object for determining whether or not to change route information are provided. It is divided into objects and the calculation time cycle can be changed for each processing, and only when traffic information changes significantly,
Since the cost update request is passed to the cost table object, it is possible to reproduce the vehicle whose route is to be changed based on the information that the traffic condition changes sequentially, so that the effect of the traffic measure that transmits the traffic information can be examined by the simulator. There is. Further, since it is possible to prevent unnecessary change of the route information, there is an effect that the total calculation time can be shortened. According to a third aspect of the present invention, in the first or second aspect of the present invention, the shortest path is searched by the entire network excluding the entered link for each entry direction at each branch point, and the selected path is selected. Does not exist, the value of the cost is specifically set to “−∞”. Therefore, in order to calculate the required cost in the shortest route from each branch point to the destination, the “route making a U-turn” is not selected. Therefore, there is an effect that a route that does not reach the destination without making a U-turn can be prevented from being selected.

[Brief description of the drawings]

FIG. 1 is a schematic processing flow in determining a traffic flow simulation route according to an embodiment of the present invention.

FIG. 2 is a relationship diagram between objects according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a road network according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a route search when a link AB according to an embodiment of the present invention is set as a departure link.

FIG. 5 is a configuration diagram of a cost table according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating a route determination process in an initial stage of an embodiment of the present invention.

[Explanation of symbols]

 1 node object 2 link object 3 vehicle object 4 cost table object 5 traffic information notification means object

Claims (4)

[Claims] In a traffic flow simulation having communication means for communicating traffic information to individual vehicles, a route change means is provided, and only required costs in the shortest route from each departure point and each branch point to a destination are stored. A route selection method in a traffic flow simulation wherein a route from a current position to a destination is sequentially selected and determined when a vehicle is generated and when a driver obtains traffic information. 2. A cost table object having a shortest route search process and a traffic information notifying unit object for determining whether or not to change route information are divided into a vehicle object for moving a vehicle, and a calculation time period can be changed for each process. Only if traffic information changes significantly,
The route selection method in the traffic flow simulation according to claim 1, wherein the cost update request is passed to a cost table object. 3. For each entry direction at each branch point, the shortest path is searched by all networks except for the entered link, and when there is no selected path, a special cost value is set to “−”. The route selection method in the traffic flow simulation according to claim 1 or 2, wherein "∞" is set. 4. A route selection method in a traffic flow simulation according to claim 1, wherein a vehicle for which traffic information has been obtained is targeted.