JP2006105686A - Route search system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a route search system, taking into consideration the a traffic situation for each drive lane for the route to be searched, as a whole. <P>SOLUTION: The route search system comprises a data storage section 1 for storing road network data for indicating a road system, a traffic situation information acquiring section 2 for acquiring traffic situation information, including traffic situations for each lane, and an arithmetic processing section 3. The arithmetic processing section 3 refers to acquired information by the traffic situation information acquiring section 2 from road network data stored at the data storage section 1, creates a lane system graph to current traffic situations for each lane, and searches for a route from the set departing point to the destination, using the lane system graph created by a graph creation section. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a route search device, and more particularly to a route search device that searches for a route from a departure point of a vehicle to a destination.

Conventionally, several methods for guiding and guiding vehicles in lane units have been proposed.
First, the first conventional example will be described. As shown in FIG. 13, it is assumed that a traffic jam J1 occurs on the link L1. This link L1 represents a road section having three lanes, and contacts the link L2 in the right turn direction via the node N. Here, the link L2 represents a road section having one lane, and it is assumed that a traffic jam J2 occurs on the link L2. In such a case, the route search device according to the first conventional example recognizes that a traffic jam has occurred in the right turn lane of the link L1 according to the received traffic jam information, and then a large link in the right turn lane of the link L1. On the contrary, a small link cost is set for the straight lane and / or the left turn lane of the link L1. Using the road network data in which such link costs are set, the route search device searches for a route from the departure place to the destination (see, for example, Patent Document 1).

In the second conventional example, the guidance apparatus first searches for a route from the departure place to the destination, and displays the searched route together with the map screen on the display. In addition, the imaging device images the situation of the traveling lane ahead of the host vehicle, and based on the image data obtained as a result, the guidance and guidance device determines whether the traveling lane of the host vehicle is appropriate in light of the searched route. If the traveling lane of the host vehicle is not appropriate as a result of the determination, the driver is warned to change the traveling lane (see, for example, Patent Document 2).
JP 2002-250635 A JP 2001-82975 A

  As described above, in the first conventional example, the route search apparatus can set the link cost only for the link representing the road section entering the intersection. In the second conventional example, after a well-known route search is performed, the guidance and guidance device uses the image data from the imaging device to identify the location where the traffic jam has occurred in real time, and guides the traveling lane. However, in any of the conventional examples, there is a problem that the traffic situation cannot be considered for each traveling lane for the entire route to be searched.

  Therefore, an object of the present invention is to provide a route search device that takes into consideration the traffic situation of each traveling lane for the entire route to be searched.

  In order to achieve the above object, a first aspect of the present invention is a route search device, comprising a data storage unit that stores road network data representing a road network, and traffic condition information including traffic conditions for each lane. A graph for creating a lane network graph suitable for the current traffic situation for each lane by referring to the information acquired by the first acquisition unit from the first acquisition unit to be acquired and the road network data stored in the data storage unit A creation unit; and a route search unit that searches for a route from the set departure point to the destination using the lane network graph created by the graph creation unit.

  Preferably, the traffic situation information includes position information capable of specifying a change point of the traffic situation, and the road network further includes a plurality of basic nodes representing feature points on the road network and two features. It is expressed using a plurality of basic links each representing a road segment between points. Here, the graph creation unit includes a copy link creation unit that creates a number of copy links corresponding to the number of lanes existing in the target road section from a basic link representing a road section in the road network data, and a copy link creation unit A temporary node creating unit that creates a temporary node based on position information included in the acquired information by the first acquiring unit for each of the copy links representing lanes adjacent to each other among the copy links created in step A plurality of first temporary links obtained by dividing adjacent copy links at each temporary node created by the creation unit and a second temporary link connecting the temporary nodes created by the temporary node creation unit And a temporary link creating unit for creating

  The temporary node creation unit preferably creates a first temporary node that creates at least one change point included in the acquisition information by the first acquisition unit on one of the copy links representing lanes adjacent to each other. Temporary node creation unit and second temporary node creation for generating a second temporary node at a position close to the first temporary node in a copy link adjacent to the one processed by the first temporary node creation unit Part. Here, the temporary link creation unit logically connects the first temporary node created by the first temporary node creation unit and the second temporary node created by the second temporary node creation unit. To create a second temporary link.

  Preferably, the traffic condition information includes average speed information indicating that the vehicle is traveling in a section where the traffic condition in the road network is changing. Here, the graph creation unit further includes a second acquisition unit that obtains average speed information from the acquisition information obtained by the first acquisition unit, and a second temporary link created by the temporary link creation unit. A cost allocating unit that allocates a cost determined based on the average speed information acquired by the second acquiring unit is included in the change section.

  Preferably, the route search unit searches for a route that can reach the set destination in the shortest time.

  Moreover, the second aspect of the present invention is a method for searching for a route using road network data representing a road network, wherein a first acquisition step of acquiring traffic condition information including traffic conditions for each lane. And from the road network data, referring to the acquisition information in the first acquisition step, a graph creation step for creating a lane network graph suitable for the current traffic situation for each lane, and from the set departure point to the destination A route search step of searching for a route using the lane network graph created in the graph creation step.

  According to a third aspect of the present invention, there is provided a computer program for searching for a route using road network data representing a road network, the first acquisition for acquiring traffic condition information including traffic conditions for each lane. From the step and road network data, referring to the acquisition information in the first acquisition step, a graph creation step for creating a lane network graph suitable for the current traffic situation for each lane, from the set departure point to the destination A route search step for searching for the route using the lane network graph created in the graph creation step.

  According to the above first to third aspects, the route search device creates a lane network graph from the road network data with reference to the acquired traffic situation information. By using such a lane network graph, the route search device can perform a route search in consideration of traffic conditions for each traveling lane interposed from the departure place to the destination.

  FIG. 1 is a block diagram showing a configuration of a route search apparatus according to an embodiment of the present invention. In FIG. 1, a route search apparatus is typically mounted on a moving body such as a vehicle (hereinafter referred to as a host vehicle), and includes a data storage unit 1, a traffic condition information acquisition unit 2, an arithmetic processing unit 3, The display device 4 is provided.

  The data storage unit 1 illustratively includes a storage medium such as a hard disk, DVD, CD, or semiconductor memory. Road network data is mainly recorded on such a storage medium. The road network data may be general, and the road network is expressed using a graph composed of nodes and links. For convenience of the following description, the nodes and links constituting the road network data are referred to as basic nodes and basic links.

  Here, the basic node represents a feature point represented by an intersection, a bending point, and a dead end point in the road network. Also, each such basic node is assigned a unique identification number (hereinafter referred to as a node number), and further, attribute information indicating the attribute of the target feature point is assigned. Here, typical attributes of the feature point include the type (intersection, inflection point or dead end point), position, and shape of the target feature point. In addition, examples of the feature point attributes include link numbers (described later) of two basic links connected to the target feature point, and traffic restrictions set for the target feature point.

  The basic link represents a road section connecting two feature points. Each such basic link is assigned a unique identification number (hereinafter referred to as a link number), and is further assigned attribute information indicating the attribute of the target road section. Here, examples of the attributes of the road section include feature points located at both ends of the target road section, that is, node numbers of the respective basic nodes, and traffic regulations set in the target road section. Further, in this embodiment, as an example, the attribute of the road section further includes a travel time assumed to be required for the vehicle to travel on the target road section, and the number of travel lanes existing in the target road section. Assigned to a link.

  The traffic condition information acquisition unit 2 is typically a receiver for receiving traffic condition information It sent from the outside. A typical example of such a receiver is a VICS (Vehicle Information and Communication System) receiver.

Here, FIG. 2 is a schematic view illustrating the data structure of the traffic situation information It acquired by the traffic situation information acquisition unit 2 shown in FIG. In FIG. 2, the traffic condition information It applies data distributed by the VICS, and includes header information H including the number of unit records M and M unit records UR ₁ − following the header information H. Includes UR _M. Each unit record UR is illustratively created for each currently occurring traffic jam and includes a link number, section information, lane number, average density, and average speed.

  The link number is a number for identifying a road section (that is, a link) in which a target traffic jam occurs.

The section information indicates the start position and end position of the target traffic jam.
The lane number is a number for identifying the lane in the road section where the target traffic jam occurs.
The average density is an approximate number indicating how many vehicles are present per unit distance during the target traffic jam.
The average speed is an approximate number indicating the average speed of each vehicle existing in the target traffic jam.

  In most cases, the link number and lane number used in VICS are different from the link number and lane number used in road network data. However, in this embodiment, for convenience of explanation, the VICS link number and lane number will be described as matching those of the road network data. Even if the link number and the lane number are not matched between the VICS and the road network data, the link number and the lane number are stored in the data storage unit 1 because the link number and the lane number of the VICS are known. By storing a conversion table from VICS to road network data for numbers, it is easy to eliminate the above-mentioned adverse effects related to the correspondence.

  The arithmetic processing unit 3 typically includes a ROM 31, a RAM 32, and a CPU 33. The ROM 31 stores a computer program necessary for the operation of the route search device. The RAM 32 is used as a work area when executing this computer program. The CPU 33 executes the computer program while using the RAM 32 as a work area. As a characteristic process, the CPU 33 generates a lane network graph according to the current traffic situation from the road network data, using the traffic situation information It generated by the traffic situation information acquisition unit 2, and then generates the lane network graph. The route from the set departure point to the destination is searched using the lane network graph.

The display device 4 displays an image according to various image data Di generated by the arithmetic processing unit 3.
Next, the operation of the route search apparatus having the above configuration will be described with reference to the flowchart of FIG.

  First, the traffic situation information acquisition unit 2 receives the traffic situation information It as described above and stores it in the RAM 32 of the arithmetic processing unit 3 (step ST1).

  In the arithmetic processing unit 3, the CPU 33 creates image data Dia representing the current traffic situation from the traffic situation information It stored in the RAM 32, and transfers it to the display device 4. The display device 4 displays an image representing the current traffic situation according to the received image data Dia (step ST2).

  Here, FIG. 4 is a schematic diagram illustrating an example of the image displayed in step ST2. In FIG. 4, for reference, an example of an actual traffic situation on the road R is schematically drawn on the left side of the page, and an example of a display image is drawn on the right side of the page.

  As shown on the left side of FIG. 4, the road R has two traveling lanes La and Lb. In the travel lane La, the road section Sa drawn in the upper part of the page is relatively free. In the road section Sa, the average speed is relatively high (for example, 30 km / h or more), and the average density is Relatively low. Further, in the travel lane La, the road section Sb drawn in the middle of the page is congested. In this road section Sb, the average speed is relatively low (for example, less than 5 km / h), and the average density is relative. Expensive. Furthermore, in the travel lane La, the road section Sc drawn in the lower part of the page is relatively free like the road section Sa. In the road section Sd of the lane Lb, the vehicle is flowing moderately. In the road section Sd, the average speed is normal (for example, 5 km / h or more and less than 30 km / h), and the average density is normal. is there.

  When the traffic situation information It representing such a traffic situation is received, the object representing the road R in the image data Dia generated by the CPU 33 is color-coded according to the degree of congestion of each road section Sa-Sd. be painted. In the example on the right side of FIG. 4, in the object of the road R, the portion representing the section Sb with the high average density is exemplarily drawn in red, the sections Sa and Sc with the low average density are exemplarily drawn in blue, The section Sd having a moderate average density is illustratively drawn in yellow. The display device 4 displays an image according to such image data Dia. By referencing such an image, the driver can select which lane on the road R to travel. It is more preferable that the lane in which the host vehicle is currently traveling or the traveling direction of the host vehicle is superimposed on the image shown in FIG.

  FIG. 5 is a schematic diagram showing an alternative example of the image displayed in step ST2. Compared with the image shown in FIG. 4, the image shown in FIG. 5 shows the object V representing the own vehicle and the lane change point where the own vehicle can avoid the traffic jam on the object representing the road R in the image data Dia. The difference is that two arrows Wa and Wb are superimposed. Other than that, there is no difference in the display images shown in FIGS. Therefore, in FIG. 5, the same reference numerals are given to the elements corresponding to the elements shown in FIG. An image as shown in FIG. 5 is displayed before the vehicle reaches the traffic jam, and the driver can change the lane to avoid the traffic jam with a margin by referring to the display image. It becomes.

  Refer to FIG. 3 again. After the end of step ST2, the CPU 33 uses the road network data stored in the data storage unit 1 and the traffic condition information It acquired in step ST1 to match the current traffic condition for each lane. Is created on the RAM 32 (step ST3).

  Here, FIG. 6 is a flowchart showing a detailed processing procedure of step ST3. In FIG. 6, the CPU 33 duplicates each basic link of the road network data on the RAM 32 by the number of traveling lanes assigned as attribute information (step ST11). The basic link duplicated in this way is referred to as a copy link in the following description. Here, for convenience of explanation, both end nodes of each copy link created from the same basic link are the same as both end basic nodes assigned as attribute information to the basic link. By such processing, a first intermediate lane network bluff in lane units called a multipath graph in graph theory is created on the RAM 32.

  Next, the CPU 33 converts the basic node included in the first intermediate lane network graph, whose type is an intersection, as shown in FIG. 7, into Na (refer to the hatched portion), to several intersections. The link is converted into a link CL (illustrated five intersection links CLa-CLe) (step ST12). Specifically, in FIG. 7, a plurality of copy links AL (seven copy links ALa-ALg in the figure) connected to the target basic node Na are connected to each other by intersection links CLa-CLe. However, in such a connection, there is a copy link that is not connected by the intersection link because of traffic restrictions set at the target intersection or the traveling direction of the copy link. As a specific example, a copy link that enters a target basic node is connected only to a copy link that exits from the target basic node. By such a process, a second intermediate lane network graph is created on the RAM 32.

  Next, the CPU 33 extracts all the section information from the currently received traffic condition information It, that is, all the combinations of the start position and the end position of the traffic jam (step ST13).

  Furthermore, the CPU 33 creates several temporary nodes and temporary links on the second intermediate lane graph based on the start position and end position extracted this time (step ST14).

  Here, FIG. 8 is a flowchart showing a detailed processing procedure of step ST14. In FIG. 8, the CPU 33 first selects a copy link that constitutes the second intermediate lane network graph including the start position and the end position that have been extracted this time (hereinafter referred to as a traffic jam copy link) (step ST21). .

  Next, the CPU 33 generates a first temporary node as an example of a temporary node at a position corresponding to the start position or the end position extracted this time in each of the traffic jam copy links selected this time (step ST22).

  Further, the CPU 33 divides each congestion copy link at each of the first temporary nodes as described above, and creates at least two first temporary links as an example of the temporary link for each congestion copy link ( Step ST23). Thereafter, the CPU 33 assigns cost information representing travel time required for the vehicle to pass through each first temporary link as attribute information to each first temporary link (step ST24). Here, the distance of each of the first temporary links is easily known, and the average speed of the vehicle when traveling on the first temporary link is obtained from the traffic condition information It received this time. Therefore, the travel time is approximated by the distance of the first temporary link / the average speed of the vehicle. In the present embodiment, the travel time is illustratively assigned to the first temporary link. However, the present invention is not limited to this, and a value correlated with the travel time may be assigned as cost information.

  Next, the CPU 33 selects the one adjacent to the traffic jam copy link selected this time (hereinafter referred to as the adjacent copy link) from the second lane network graph (step ST25).

  Next, the CPU 33 generates a second temporary node as another example of the temporary node at a position close to the start position or the end position extracted this time in each of the adjacent copy links selected this time (step) ST26). As a preferred example, the second temporary node is generated at the intersection of the perpendicular line from the start position or the end position to the adjacent copy link and the adjacent copy link.

  Next, the CPU 33 logically connects the first temporary node and the second temporary node adjacent to each other, and creates some second temporary links as another example of the temporary links ( Step ST27).

  Further, the CPU 33 divides each adjacent copy link at each of the second temporary nodes as described above, and creates at least two third temporary links as an example of the temporary link for each adjacent copy link. Further, the CPU 33 assigns cost information for each third temporary link as attribute information to each third temporary link in the same manner as in step ST24 (step ST28).

  Next, the CPU 33 sets at least a destination node indicating the destination among the starting point and destination set by a known method as a copy link in the third intermediate lane network graph (step ST29). By such processing, an intermediate lane network graph suitable for route search for each lane is generated on the RAM 32.

  The process of FIG. 8 is completed by the above step ST29, and the process of FIG. 6 and further the process of step ST3 of FIG. 3 are completed. By such processing, a third intermediate lane graph is created on the RAM 32.

  Here, FIG. 9 is a schematic diagram showing an example of the first and second temporary nodes and the first and second temporary links generated by the processes from step ST21 to ST28 shown in FIG. In FIG. 9, for reference, a display image based on the same image data Dia as shown in FIG. 4 is drawn on the left side of the page, and the road drawn on the left side of the page is shown on the right side of the page. For R, two first temporary nodes N1a and N1b, two second temporary nodes N2a and N2b, three first temporary links L1a, L1b and L1c, and two second Temporary links L2a and L2b and three third temporary links L3a, L3b and L3c are depicted.

  When step ST3 shown in FIG. 3 is completed, the CPU 33 searches for the route to the set destination node using the lane network graph generated this time, and further, the vehicle follows the searched route. The total travel time is estimated when traveling up to (step ST4). As for route search, a lane network graph and road network data are similar in terms of belonging to the graph, and therefore, a well-known algorithm represented by the Dijkstra method can be applied. In step ST4, as a preferred example, the CPU 33 searches for a route that can reach the destination in the minimum total travel time.

  Thereafter, the CPU 33 preferably creates image data Div representing the total travel time estimated in step ST4 in the RAM 32 and transfers the image data to the display device 4. The display device 4 displays an image representing the total travel time in accordance with the received image data Div. Thereafter, the CPU 33 provides guidance to the destination according to the searched route for each lane (step ST5).

  Here, FIG. 10 is a schematic diagram showing a part of a route obtained as a result of executing step ST4 shown in FIG. FIG. 9 shows a part of the road network graph obtained by the processing from step ST21 to ST28 shown in FIG. 8 for reference. Compared with the road network graph shown in FIG. 10, the cost information C1a assigned to the first temporary link L1a and the cost information C1b assigned to the first temporary link L1b are compared with those shown on the right side of FIG. It is shown. Further, cost information C1c assigned to the first temporary link L1c, cost information C2a assigned to the second temporary link L2a, and cost information C2b assigned to the second temporary link L2b are shown. Further, cost information C3a assigned to the third temporary link L3a, cost information C3b assigned to the third temporary link L3b, and cost information C3c assigned to the third temporary link L3c are shown. Here, in FIG. 10, it is assumed that at least the cost information C1a, C3b, and C1c is smaller than the other cost information. When step ST4 is executed for such a road network graph, the first temporary link L1c → the second temporary link L2b → the third temporary link, as indicated by the five arrows on the right side of FIG. A route that follows L3b → second temporary link L2a → first temporary link L1a is searched.

  FIG. 11 shows an example of the destination node (destination node Nd) generated by the process of step ST29 shown in FIG. 8 and the last part of the route obtained as a result of executing step ST4 shown in FIG. It is a schematic diagram shown. On the left side of FIG. 11, the destination node Nd is set at a location closest to the set destination on the first or third temporary link regardless of the value of the cost information assigned to each. In the illustrated example, the destination node Nd is set on the first temporary link L1p. Here, it is assumed that the value of the cost information C1p assigned to the first temporary link L1p is larger than that of the third temporary link L3p adjacent thereto. That is, a traffic congestion that is worse in the road section represented by the first temporary link L1p than in the road section represented by the third temporary link L3p occurs. When step ST4 is performed on such a road network graph, a route passing through the first temporary link L1p as indicated by three arrows on the right side of FIG. 11 is searched. As a result, as shown on the right side of FIG. 12, the route search device can guide the vehicle at the end of the traffic jam occurring on the first temporary link L1p.

  As described above, the route search device according to the present embodiment generates a copy link corresponding to the number of lanes from each basic link constituting the road network data. The route search device acquires a change point of the current traffic situation such as a start point and an end point of a traffic jam from the acquired traffic condition information It, and obtains a first temporary node indicating such a change point. The target copy link is generated at an appropriate position of the target copy link, and the target copy link is further divided by such a first temporary node as a boundary, thereby generating the first temporary link. Further, the route search device generates a second temporary node at a position close to such a change point in the adjacent copy link, connects the first and second temporary nodes, and sets the second temporary link. Generate. By using the lane network graph generated in this way, the route search device can perform a route search in consideration of the traffic situation for each traveling lane interposed from the departure place to the destination. Furthermore, such a route search makes it possible to estimate the required time to the destination with higher accuracy than in the past.

  Further, according to the route search device according to the present embodiment, immediately after performing the route search, the time required to reach the destination in consideration of the traffic situation at that time can be known, so the route search device is more convenient than the conventional one. Can be provided.

  In the above embodiment, a traffic jam has been described as an example of the traffic situation, but other examples of the traffic situation include traffic accidents, traffic regulation, and road construction. According to the present embodiment, it is possible to perform a lane-based route search that can avoid these traffic accidents, traffic restrictions, and road construction.

  Moreover, although the VICS receiver was mentioned as an example of the traffic condition information acquisition part 2 in the above embodiment, it is not restricted to this, The traffic condition information acquisition part 2 may be as follows. That is, the center station collects, for example, a place where traffic congestion occurs and the average density and average speed in the traffic congestion via vehicle-to-vehicle communication or road-to-vehicle communication. Such traffic situation information It is generated and data broadcasted. The traffic condition information acquisition unit 2 receives such data broadcasting. Alternatively, the center station may alternatively collect the above-described information from a large number of traffic measurement devices installed in the road network, a large number of sensors embedded in the roadside belt, or the median strip.

  In the above embodiment, the first intermediate lane network graph is created in step ST11. However, the present invention is not limited to this, and the road network data may originally be a multipath graph. In this case, the basic link constituting the road network data corresponds to the copy link in the above-described embodiment.

  The computer program stored in the ROM 31 constituting the arithmetic processing unit 3 may be distributed in a state of being stored in a recording medium represented by a CD-ROM, or provided to various terminal devices through a digital network. It doesn't matter.

  The route search device according to the present invention is useful for in-vehicle applications and the like that require the effect of being able to take into account the traffic situation for each travel lane of the entire route.

The block diagram which shows the structure of the route search apparatus which concerns on one Embodiment of this invention. The schematic diagram which illustrates the data structure of the traffic condition information It which the traffic condition information acquisition part 2 shown in FIG. 1 acquires The flowchart which shows operation | movement of the route search apparatus shown in FIG. Schematic diagram showing an example of an image displayed in step ST2 shown in FIG. Schematic diagram showing an alternative example of the image displayed in step ST2 shown in FIG. The flowchart which shows the detailed process sequence of step ST3 shown in FIG. Schematic diagram showing the processing content of step ST12 shown in FIG. The flowchart which shows the detailed process sequence of step ST14 shown in FIG. Schematic diagram showing an example of the first and second temporary nodes and the first and second temporary links generated by the processing from step ST21 to ST28 shown in FIG. Schematic diagram showing a part of the path obtained as a result of executing step ST4 shown in FIG. Schematic diagram showing an example of the destination node (destination node Nd) generated by the process of step ST29 shown in FIG. 8 and the last part of the route obtained as a result of executing step ST4 shown in FIG. Schematic diagram showing lane change guidance immediately before the destination by the route search device shown in FIG. Schematic diagram showing guidance guidance processing by a conventional route search device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Data storage part 2 Traffic condition information acquisition part 3 Arithmetic processing part 4 Display apparatus

Claims (7)

A route search device,
A data storage unit for storing road network data representing the road network;
A first acquisition unit that acquires traffic condition information including traffic conditions for each lane;
From the road network data stored in the data storage unit, referring to the acquisition information by the first acquisition unit, a graph creation unit that creates a lane network graph suitable for the current traffic situation for each lane;
A route search device comprising: a route search unit that searches for a route from a set departure point to a destination using a lane network graph created by the graph creation unit. The traffic situation information includes position information that can identify a change point of the traffic situation,
The road network is represented using a plurality of basic nodes representing feature points on the road network and a plurality of basic links representing road sections between two feature points, respectively.
The graph creation unit
A copy link creating unit that creates a number of copy links corresponding to the number of lanes existing in a target road section from a basic link representing a road section in the road network data;
Temporary node for creating a temporary node based on the position information included in the acquisition information by the first acquisition unit for each of the copy links representing lanes adjacent to each other among the copy links created by the copy link creation unit The creation department;
In each temporary node created by the temporary node creation unit, a plurality of first temporary links obtained by dividing adjacent copy links are connected to the temporary nodes created by the temporary node creation unit. The route search device according to claim 1, further comprising a temporary link creation unit that creates two temporary links. The temporary node creation unit
A first temporary node creation unit for creating a first temporary node indicating at least one change point included in the acquisition information by the first acquisition unit on one of the copy links representing lanes adjacent to each other;
A copy link adjacent to the one processed by the first temporary node creation unit, and a second temporary node creation unit that creates a second temporary node at a position close to the first temporary node. ,
The temporary link creation unit logically connects the first temporary node created by the first temporary node creation unit and the second temporary node created by the second temporary node creation unit. The route search device according to claim 2, wherein the second temporary link is created. The traffic situation information includes average speed information that the vehicle is traveling in a section where the traffic situation in the road network is changing,
The graph creation unit further includes:
A second acquisition unit for acquiring average speed information from the acquisition information by the first acquisition unit;
The cost of assigning a cost determined based on the average speed information acquired by the second acquisition unit to the second temporary link created by the temporary link creation unit, which represents a traffic condition change section The route search device according to claim 3, comprising an assignment unit.   The route search device according to claim 1, wherein the route search unit searches for a route that can reach the set destination in the shortest time. A method for searching a route using road network data representing a road network,
A first acquisition step of acquiring traffic condition information including traffic conditions for each lane;
From the road network data, referring to the acquisition information by the first acquisition step, a graph creation step of creating a lane network graph suitable for the current traffic situation for each lane;
A route search method comprising: a route search step for searching for a route from a set departure point to a destination using the lane network graph created in the graph creation step. A computer program for searching a route using road network data representing a road network,
A first acquisition step of acquiring traffic condition information including traffic conditions for each lane;
From the road network data, referring to the acquisition information by the first acquisition step, a graph creation step of creating a lane network graph suitable for the current traffic situation for each lane;
A computer program comprising: a route search step for searching for a route from a set departure point to a destination using the lane network graph created in the graph creation step.

Images