JP2010210286A - Route search method, route search device, computer program for performing route search, and recording medium on which the computer program is recorded - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that direct guidance to a destination is not performed when the closest road to a destination is a narrow street. <P>SOLUTION: A trunk road in the vicinity of the destination (target trunk road) is specified for the destination in a narrow street network. An intersection in the trunk road allowing the access to the narrow street network surrounding the destination (target intersection) is extracted. A route search (narrow street search) from the intersection (target intersection) to the destination and a route search (main route search) from a start point to the intersection (target intersection) are independently performed, and then integrated to each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in a route search method when a nearest road of a destination or departure point is a narrow street when performing a route search with a navigation system.

Conventionally, route search has been performed exclusively on arterial roads. This is because road information has been assigned to the links and nodes constituting the main road. Here, the road information is information that defines the characteristics of the link and the node. For example, the road type is defined for the link and the presence / absence of a traffic signal is defined for the node. Such road information has been accumulated exclusively based on field surveys. Route cost is used to preferentially search for routes that do not burden the driver. The route cost is determined by adding cost information determined for each link and node for all links and nodes of the searched route. Cost information is specified based on road information.
On narrow streets, the burden on the driver increases. Therefore, Patent Document 1 describes a method for searching for a route for exiting from a narrow street to a main road. Reference should be made to Patent Document 2 as a document disclosing other techniques related to the present application.

JP 2008-232956 A JP 2004-347539 A

Recently, more detailed guidance has been required for navigation devices. For example, even when the nearest road of a destination is a narrow street, a search for a route that can be guided directly to the destination is required.
However, conventionally, accumulation of road information related to narrow streets is insufficient. For example, when the nearest road of a destination is a narrow street, there are many cases where direct guidance to the destination is not possible. In that case, the point of the main road closest to the destination is set as the guidance end point, and the route search to this guidance end point is limited. Then, from the guidance end point to the destination, the driver will drive the narrow street by his own judgment while looking at the map and looking at the surrounding scenery and signs. Since narrow streets are narrow and there are many regulations such as temporary suspension and one-way traffic from the viewpoint of ensuring the safety of pedestrians, driving is burdensome.

An object of the present invention is to solve the above problems. The first aspect of the present invention is defined as follows. That is,
A route search method when the nearest road of the first designated place of the route is a narrow street,
A target main road to be communicated to the first designated place through the narrow street or through the narrow street and other narrow streets connected to the narrow street and without any other main road is specified. Steps,
Extracting the target intersection in the forward direction in the vehicle traveling direction in the route, which is an intersection of the target main road and the narrow street and / or the other narrow street;
Searching for a route with the smallest route cost in the narrow street and / or the other narrow street route connecting the first designated place and the target intersection, and designating the searched route as a narrow street route When,
Searching for a main route between the first target passing intersection and the second designated place of the route, with the target intersection on the narrow street route as a first target passing intersection;
A route search method comprising:

  When the first designated place is the destination and the second designated place is the starting place, if the nearest road of the destination is a narrow street, the nearby main road (target main road) to the destination Identify the intersection (target intersection) that can enter the narrow street that leads to the destination on the main road, and search for the route from this intersection (target intersection) to the destination (narrow street search) and the departure point A route search (main route search) to this intersection (target intersection) is performed separately. The latter main route search is covered by general-purpose functions provided in the navigation device. The former narrow street search is a newly required function for the navigation device, but it is a route search in a narrow range of the destination and the nearby main road, so the burden on the navigation device even if special processing is performed The time required for route search does not increase unnecessarily.

Here, the designated place of the route includes not only the above-mentioned destination or departure place but also a waypoint that can be designated on the navigation system.
The target main road is directly connected to the narrow street adjacent to the first designated place, or is directly connected to another narrow street connecting to the narrow street, and another main road between the target main road and the destination. Do not intervene. In that sense, a plurality of target trunk roads may be specified.
In this specification, a narrow street adjacent to the first designated place and other narrow streets connected to the narrow street may be expressed as a narrow street network.

The target intersection extracted on the target main road is forward in the vehicle traveling direction on the route. Here, the forward direction means that the vehicle is not restricted at all. For example, when the first designated place is the destination, the intersection at which the main road and the narrow street network are allowed to enter the destination is the target intersection. An intersection that cannot enter the narrow street network from a main road due to restriction of the direction of travel such as one-way traffic cannot be a target intersection. On the other hand, when the first designated place is the departure place, an intersection that can exit from the narrow street network on the departure side to the trunk road at the intersection of the main road and the narrow street network becomes the target intersection.
The departure point means the departure point at the time when the route search is performed, and the current location of the vehicle is often the departure point. Of course, a point other than the current location of the vehicle can be designated as the departure point.

  The route cost concept can be used when specifying the optimum route between the first designated place in the narrow street network and the target intersection. A route cost is obtained by adding the cost information of each narrow street (link) and each intersection (node) along the route searched in the narrow street network, and the one having the smallest route cost is a narrow street route.

In the information installed in the navigation device, the information related to the narrow street is generally about the map information as a drawing target on the display. The map information is information indicating the position of the narrow street on the map, and this information is also used for map matching. However, map information alone cannot be used for route search, and cannot be basic information for determining cost information of narrow street links and nodes. This is because, if information similar to a main road is given to links and nodes on narrow streets, the amount of data becomes enormous and the burden on the navigation system increases.
On the other hand, the main road defined in the present invention refers to a road that can be searched in the general-purpose road search function of the navigation system. Such main roads are preliminarily provided with map information and road information. For example, information related to road types as road information, information related to the number of lanes, etc. are given corresponding to links as map information, and information related to the presence or absence of traffic lights as road information corresponding to nodes as map information, etc. It is done. By making the road information correspond to a predetermined “road information-cost information table”, the cost information can be specified for each link and node. Of course, unique cost information can be assigned to the link and the node in advance.

In this invention, the cost information of each link and each node constituting the narrow street network to which the first designated place belongs is specified by a special method, and the first designated place and the target intersection are connected using this cost information. The route cost of the route is calculated, and the route with the lowest route cost (narrow street route) is searched.
Here, the cost information of each link and each node constituting the narrow street network is calculated using map information given to the narrow street.
As map information, it is possible to use (1) the number of right / left turns at the intersection of the narrow street network, (2) the number of intersections at the intersection, and (3) the intersection angle between the approach path and the exit path.
That is, the second aspect of the present invention is defined as follows.
In the route search method according to the first aspect, the route cost of the narrow street route refers to at least one of the number of right / left turns at the narrow street intersection, the number of crossings, and the intersection angle between the approach route and the exit route. Calculated.

When the navigation system includes traffic regulation data separately from the road information, the cost information of each link and each node constituting the narrow street network can be calculated using the traffic regulation data. Here, for example, digital traffic regulation data provided by the Japan Traffic Management Technology Association can be used as the traffic regulation data. Among traffic regulation data, it is preferable to use one-way data or temporary stop data.
That is, the third aspect of the present invention is defined as follows.
In the route search method according to the first or second aspect, the route cost of the narrow street route is calculated with reference to one-way data and / or temporary stop data.

If the nearest road is a narrow street, the target intersection A through which the first route specified by the route search from the departure point to the destination passes, and the departure point as the departure point. It does not necessarily coincide with the target passing intersection B through which the second route specified by the route search from to the destination passes.
So, so that the driver can feed the so-called land can at the waypoint, after exiting from the narrow street network surrounding the waypoint through the narrow street route B to the main road, the main route B passes the target as the second waypoint It is preferable to set the intersection A. As a result, after leaving the transit point and exiting from the target passing intersection B to the main road, it is possible to pass again through the target passing intersection A that has already passed through the main road. Nourished.
That is, the fourth aspect of the present invention is defined as follows.
In the route search method according to any one of the first to third aspects, when the nearest road of the waypoint is a narrow street, a target passing intersection A that contacts the waypoint in the route from the departure point to the waypoint is determined. Save and
Save the target passing intersection B connecting to the waypoint in the route from the waypoint to the destination,
In the main route from the target passing intersection B to the destination, the target passing intersection A is set as a second waypoint.

The fifth aspect of the present invention is defined as follows. That is,
A route search device when the nearest road of the first designated place of the route is a narrow street,
A target main road to be communicated to the first designated place through the narrow street or through the narrow street and other narrow streets connected to the narrow street and without any other main road is specified. The target highway identification part,
A target intersection extraction unit that extracts a target intersection in a forward direction in the vehicle traveling direction in the route, which is an intersection of the target main road and the narrow street and / or the other narrow street;
A narrow street route that searches for a route with the smallest route cost in the narrow street and / or the other narrow streets connecting the first designated place and the target intersection, and designates the searched route as a narrow street route A search unit;
A main route search unit for searching for a main route between the first target passing intersection and the second designated place of the route, with the target intersection on the narrow street route as a first target passing intersection;
A route search device comprising:
According to the route search device of the fifth aspect defined in this way, the same effect as the first aspect can be obtained.

The sixth aspect of the present invention is defined as follows. That is,
In the route search device of the fifth aspect, the route cost of the narrow street route is calculated with reference to at least one of the number of right / left turns at the narrow street intersection, the number of crossings, and the intersection angle between the approach route and the exit route. The
According to the route search device of the sixth aspect defined in this way, the same effect as the second aspect can be obtained.

The seventh aspect of the present invention is defined as follows. That is,
In the route search device according to the fifth or sixth aspect, the route cost of the narrow street route is calculated with reference to one-way data and / or temporary stop data.
According to the route search device of the seventh aspect defined in this way, the same effect as the third aspect can be obtained.

The eighth aspect of the present invention is defined as follows. That is,
In the route search device according to any one of the first to third aspects, when the nearest road of the waypoint is a narrow street, the target passing intersection that contacts the waypoint in the route from the departure place to the waypoint Save A,
Save the target passing intersection B connecting to the waypoint in the route from the waypoint to the destination,
In the main route from the target passing intersection B to the destination, the target passing intersection A is set as a second waypoint.
According to the route search device of the eighth aspect defined in this way, the same effect as the fourth aspect can be obtained.

Furthermore, the ninth aspect of the present invention is defined as follows. That is,
A computer program for searching a route when the nearest road of a first designated place of a route is a narrow street,
A target main road to be communicated to the first designated place through the narrow street or through the narrow street and other narrow streets connected to the narrow street and without any other main road is specified. Means,
Means for extracting a target intersection in the forward direction in the vehicle traveling direction in the route, which is an intersection between the target main road and the narrow street and / or the other narrow street;
Means for searching for a route with the smallest route cost in the narrow street and / or the other narrow street connecting the first designated place and the target intersection, and designating the searched route as a narrow street route;
Means for searching for a main route between the first target passing intersection and the second designated place of the route, with the target intersection on the narrow street route as a first target passing intersection;
A computer program characterized by functioning as:
According to the computer program of the ninth aspect defined in this way, the same effect as in the first aspect can be obtained.

The tenth aspect of the present invention is defined as follows. That is,
In the computer program according to the ninth aspect, the route cost of the narrow street route is calculated with reference to at least one of the number of right / left turns at the narrow street intersection, the number of crossings, and the intersection angle between the approach route and the exit route. .
According to the computer program of the 10th aspect prescribed | regulated in this way, the effect similar to a 2nd aspect is acquired.

The eleventh aspect of the present invention is defined as follows. That is,
In the computer program according to the ninth or tenth aspect, the route cost of the narrow street route is calculated with reference to one-way data and / or temporary stop data.
According to the computer program of the 11th aspect prescribed | regulated in this way, the effect similar to a 3rd aspect is acquired.

The twelfth aspect of the present invention is defined as follows. That is,
In the computer program according to any one of the ninth to eleventh aspects, when the nearest road of the waypoint is a narrow street, the computer is
Save the target passing intersection A connecting to the waypoint in the route from the departure point to the waypoint,
Save the target passing intersection B connecting to the waypoint in the route from the waypoint to the destination,
Means for setting the target passing intersection A as a second waypoint in the main route from the target passing intersection B to the destination;
To function as.
According to the computer program of the 12th aspect prescribed | regulated in this way, the effect similar to a 4th aspect is acquired.

  A recording medium for recording the computer program defined in the ninth to twelfth aspects is defined as the thirteenth aspect.

FIG. 1 is a block diagram showing a configuration of a navigation system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a detailed configuration of the route search apparatus in FIG. FIG. 3 is a schematic diagram showing the relationship between the destination and the target main road. FIG. 4 is a schematic diagram showing a target intersection. FIG. 5 is a flowchart showing the operation of the navigation system. FIG. 6 is a flowchart showing a first narrow street route searching method. FIG. 7 is a schematic diagram showing a first narrow street route searching method.

Embodiments of the present invention will be described below.
As shown in FIG. 1, the navigation system 1 according to the embodiment includes a control unit 3, a memory unit 4, an input unit 5, a vehicle position detection unit 6, an output unit 7, an interface unit 8, and a route search device 10. .
The control unit 3 is a computer device including a CPU, a buffer memory, and other devices, and controls other elements constituting the navigation system 1. A computer program is stored in the memory unit 4, and this computer program is read into the control unit 3, which is a computer device, and functions. This computer program can be stored in a general-purpose medium such as a DVD.

The input unit 5 is used for setting a destination and the like. A touch panel type input device that cooperates with the display content of the display can be used as the input unit 5.
The own vehicle position detection unit 6 detects the current position of the user terminal using a GPS device or a gyro device.
The output unit 7 includes a display, and displays map information and other information necessary for navigation. The output unit 7 can also include a voice guidance device.
The interface unit 8 connects the navigation system 1 to a wireless network or the like.

The route search device 10 includes a search unit 20 and an information storage unit 30. Details of the route search apparatus 10 are shown in FIG.
The search unit 20 includes a route search unit 21, a target main road identification unit 27, and a target intersection extraction unit 28. The route search unit 21 searches for a route from the departure point to the destination. In the search, the route cost is calculated, and the route with the lowest route cost is displayed at the top to be a recommended route.
In the example of FIG. 2, the route search unit 21 includes a main route search unit 23 and a sub route search unit 24. The main route search unit 23 is provided in a general-purpose navigation system, and searches for a route on an arterial road exclusively with reference to information stored in the general-purpose road information storage area 33 of the road information storage unit 30.
The sub route search unit 24 is for searching for a route in a narrow street, and includes a cost generation unit 25 and a narrow street route search unit 26. The cost generation unit 25 generates cost information for each link and node constituting the narrow street network surrounding the first designated place based on predetermined rules, and stores the cost information in the second cost information storage unit 38. The narrow street route search unit 26 reads the map information of the narrow streets stored in the second map information storage unit 37, and refers to those cost information stored in the second cost information storage unit 38 for detailed information. Search for a route on the street. The route with the smallest route cost information is recommended and becomes a narrow street route.

  The information storage unit 30 includes a first information storage unit 31, a second cost information storage unit 38, and a traffic regulation data storage unit 39. The information in the first information storage unit 31 is installed in advance and can be rewritten as necessary. The second cost information storage unit 38 generates the cost information generated by the cost generation unit 25 for the links and nodes constituting the narrow street network when the narrow street network surrounding the first designated place is specified. Associate and save. The traffic regulation data storage unit 39 stores traffic regulation data.

The first information storage unit 31 includes a map information storage unit 36 and a road information storage unit 35. The map information storage unit 36 includes a first map information storage unit 34 and a second map information storage unit 37. Map information related to the main road is stored in the first map information storage unit 34, and map information related to the narrow streets is stored in the second map information storage unit 37. Here, the map information is information necessary for drawing a road on the display device of the navigation system, and includes at least node information and link information.
The characteristic information storage unit 351 of the road information storage unit 35 is provided with information specifying the characteristics of the nodes and links in association with each node information and each link information stored in the first map information storage unit 34. . Cost information corresponding to this characteristic is stored in the first cost information storage unit 353. Therefore, for example, when a link to be stored in the first map information storage unit is specified by the main route search unit 23, the characteristics of the specified link are read from the characteristic information storage unit 351 of the road information storage unit 35. At the same time, cost information corresponding to the characteristic is read from the first cost information storage unit 353 and used for route search.

  The first map information storage unit 34 and the road information storage unit 35 constitute a general road information storage unit 33. This general-purpose road information storage unit 33 is installed in a general-purpose navigation system. In a general-purpose navigation system, the main route search unit 23 executes a route search with reference to map information and road information stored in the general-purpose road information storage unit 33.

When the nearest road of the first designated place is a narrow street, the target trunk road specifying unit 27 expands the area radially around the narrow street as shown in FIG. Identify. Further, the main roads K2, K3, and K4 that are sequentially encountered when the area is expanded are specified. These trunk roads are target trunk roads.
In this embodiment, four main roads K1 to K4 are specified so that all narrow streets of the narrow street network surrounding the destination intersect the main road.
It is sufficient that the number of arterial roads to be identified is one or more. In order to perform a more accurate narrow street search, it is preferable to specify a plurality of highways so as to completely surround the narrow street network including the first designated place.

  The trunk road identified in this way is referred to as a target trunk road in this specification. The target main road is in direct communication with the narrow street network surrounding the first designated area, and there is no other main road connected to the narrow street network between the first designated place and the target main road.

  The target intersection extraction unit 28 extracts a target intersection from the intersections on the target trunk road identified by the target trunk road identification unit 27. Here, the target intersection is an intersection in the forward direction with respect to the route to be searched. As shown in FIG. 4, when the first designated place is the destination, an intersection on the main road that can enter the narrow street network from the main road is picked up. In FIG. 4, the target intersection is marked with a cross.

Next, the operation of the navigation system will be described with reference to the flowchart of FIG.
In step 1, the destination is set by the input unit 5. The own vehicle position when the destination is set can be detected by the own vehicle position detection unit 6, and the own vehicle position can be set as the departure place.
In Step 3, it is verified whether or not the nearest road of the destination set in Step 1 is a narrow street, that is, whether or not the destination exists in the narrow street network. When the destination exists in the narrow street network, a first narrow street route is searched in step 5.

Details of the operation of step 5 are shown in FIG.
In step 51, the target trunk road identification unit 27 identifies the target trunk road K (see FIG. 3). The main road that expands the area radially from the destination and directly hits is designated as the target main road. In this example, four target main roads K1 to K4 are specified.
The target intersection extraction unit 28 extracts an intersection (target intersection) that can travel from the main road to the narrow street side from the intersections that intersect the narrow street in each target main road K1 to K4 (step 53). In executing this step, first, an intersection between the main roads K1 to K4 and the narrow street is picked up, and subsequently, it is verified whether or not the traveling direction at the intersection is a forward direction with respect to the route.

In step 54, the cost information of each narrow street of the narrow street network whose outer edge is defined by the target main road is specified, and the specified cost information is stored in the second cost information storage unit 38.
In this example, the cost information of the narrow street is specified by the cost generation unit 25 according to a predetermined rule. An example rule is shown below.
(1) The cost information C1 is given to the left and right turn at the intersection of the narrow street network.
(2) Cost information C2 is given when passing through an intersection in a narrow street network.
(3) At the intersection in the narrow street network, when the intersection angle between the approach road and the exit road is an arbitrary angle (for example, 80 degrees) or less, cost information C3 is given.
(4) The cost information C4 is given for the temporary stop.
(5) The cost information C5 is given to the narrow streets of face-to-face traffic (non-one-way traffic).
The cost information C1 to C5 can all be set to the same value (unit cost information), and the cost information C1 to C5 can be inclined.
The cost information giving process according to the rules (1) to (3) can be performed with reference to the second map information stored in the second map information storage unit. The cost information providing process according to the rules (4) and (5) can be performed with reference to the traffic regulation data stored in the traffic regulation data storage unit 39.
Further, when the narrow street width data is prepared, the cost information C6 may be added when the narrow street width is smaller than a predetermined threshold. Furthermore, the vehicle width of the own vehicle and the width of the narrow street are compared, and when the width of the narrow street is not more than a predetermined multiple of the vehicle width of the own vehicle, the cost information C7 can be given.

Returning to FIG. 6, in step 54, the narrow street route search unit 26 refers to the second map information storage unit 37 and the second cost information storage unit 38 to perform a route search between the destination and each target intersection. The route with the lowest route cost (first narrow street route) is specified. In the example of FIG. 7, the route cost of the route in which the number of right / left turns in the narrow street network is zero is minimized. Therefore, this route becomes the first narrow street route.
Returning to FIG. 5, the target intersection on the first narrow street route identified in step 54 is identified as the first target passing intersection.

In step 9, it is verified whether or not the nearest road of the departure place set in step 2 is a narrow street, that is, whether or not the departure place exists in the narrow street network. When the departure place exists in the narrow street network, a second narrow street route is searched in step 11.
The operation of step 11 is substantially the same as the search for the first narrow street route described in FIG. An intersection that can travel from the narrow street side to the main road side is extracted as the target intersection. A route search between the extracted target intersection and the departure point is performed, and the lowest route cost (second narrow street route) is specified.
In step 13, the target intersection on the second narrow street route specified in step 11 is specified as the second target passing intersection.
The reason for calculating the second narrow street route relating to the departure place after the calculation of the first narrow street route relating to the destination is that the departure place is often the vehicle position in the route search. This is because when the vehicle is started after setting the vehicle, the vehicle may leave the narrow street network and reach the main road during the route search process. If it becomes so, step 9 will become NO and the burden concerning a navigation system will be reduced.

When the destination and departure point are within the narrow street network (step 15; Y),
A route (main route) from the first target passing intersection to the second target passing intersection is searched using a general-purpose function (main route searching unit 23) provided in the navigation system (step 17).
When the nearest road of the destination is a main road and the nearest road of the departure place is a narrow street, the main route is from the second target passing intersection to the destination. When the nearest road of the departure place is a main road and the nearest road of the destination is a narrow street, the main route is from the departure place to the first target passing intersection.
When both the departure point and the destination are the main roads (step 15; N), the main route search unit searches from the departure point to the destination.

In step 19, the first and / or second narrow street route and the main route are combined.
As a result, even if the departure point and the destination are present in the narrow street network, direct guidance to the departure point and the destination is possible.

Next, an example in which the nearest road at the waypoint is a narrow street will be described.
Basically, first, a route search from a departure place to a destination is performed according to the above example. Thereby, the following first route is specified.
First route: Departure point → (Main route A) → Target passing intersection A → (Narrow street route A) → Via (Destination)
Next, the route search from the waypoint to the destination is executed according to the above example. As a result, the following second route is specified.
Second route: Via (departure point) → (narrow street route B) → target passing intersection B → (main route B) → destination

In the above, the target passing intersection A and the target passing intersection B do not necessarily match.
So, so that the driver can feed the so-called land can at the waypoint, after exiting from the narrow street network surrounding the waypoint through the narrow street route B to the main road, the main route B passes the target as the second waypoint An intersection A can be set. Thus, after leaving the waypoint and exiting from the target passing intersection B to the main road, the target passing intersection A that has already passed through the main road is again passed and guided to the destination. According to such a guidance method, since the target passing intersection A is surely passed twice, the land can in the vicinity of the waypoint is fed.
In the above, when the target passing intersection B and the target passing intersection A match, setting of the second waypoint in the main route B is not necessary.

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 1 Navigation system 10 Route search device 20 Search part 30 Information storage part

Claims (13)

A route search method when the nearest road of the first designated place of the route is a narrow street,
A target main road to be communicated to the first designated place through the narrow street or through the narrow street and other narrow streets connected to the narrow street and without any other main road is specified. Steps,
Extracting the target intersection in the forward direction in the vehicle traveling direction in the route, which is an intersection of the target main road and the narrow street and / or the other narrow street;
Searching for a route with the lowest route cost in the narrow street and / or the other narrow streets connecting the first designated place and the target intersection, and designating the searched route as a narrow street route;
Searching for a main route between the first target passing intersection and the second designated place of the route, with the target intersection on the narrow street route as a first target passing intersection;
A route search method comprising:   The route cost of the narrow street route is calculated with reference to at least one of the number of right / left turns at the narrow street intersection, the number of crossings, and the intersection angle between the approach route and the exit route. The route search method described in 1.   The route search method according to claim 1 or 2, wherein a route cost of the narrow street route is calculated with reference to one-way data and / or temporary stop data. When the nearest road of the waypoint is a narrow street, the target passing intersection A that contacts the waypoint in the route from the departure place to the waypoint is stored,
Save the target passing intersection B connecting to the waypoint in the route from the waypoint to the destination,
The route search method according to claim 1, wherein the target passing intersection A is set as a second waypoint in the main route from the target passing intersection B to the destination. A route search device when the nearest road of the first designated place of the route is a narrow street,
A target main road to be communicated to the first designated place through the narrow street or through the narrow street and other narrow streets connected to the narrow street and without any other main road is specified. The target highway identification part,
A target intersection extraction unit that extracts a target intersection in a forward direction in the vehicle traveling direction in the route, which is an intersection of the target main road and the narrow street and / or the other narrow street;
A narrow street route that searches for a route with the smallest route cost in the narrow street and / or the other narrow streets connecting the first designated place and the target intersection, and designates the searched route as a narrow street route A search unit;
A main route search unit for searching for a main route between the first target passing intersection and the second designated place of the route, with the target intersection on the narrow street route as a first target passing intersection;
A route search device comprising:   6. The route cost of the narrow street route is calculated with reference to at least one of the number of right / left turns at the narrow street intersection, the number of crossings, and the intersection angle between the approach route and the exit route. The route search device described in 1.   The route search device according to claim 5 or 6, wherein the route cost of the narrow street route is calculated with reference to one-way data and / or temporary stop data. When the nearest road of the waypoint is a narrow street, the target passing intersection A that contacts the waypoint in the route from the departure place to the waypoint is stored,
Save the target passing intersection B connecting to the waypoint in the route from the waypoint to the destination,
The route search device according to any one of claims 5 to 7, wherein the target passing intersection A is set as a second waypoint in the main route from the target passing intersection B to the destination. A computer program for searching a route when the nearest road of a first designated place of a route is a narrow street,
A target main road to be communicated to the first designated place through the narrow street or through the narrow street and other narrow streets connected to the narrow street and without any other main road is specified. Means,
Means for extracting a target intersection in the forward direction in the vehicle traveling direction in the route, which is an intersection between the target main road and the narrow street and / or the other narrow street;
Means for searching for a route with the smallest route cost in the narrow street and / or the other narrow street connecting the first designated place and the target intersection, and designating the searched route as a narrow street route;
Means for searching for a main route between the first target passing intersection and the second designated place of the route, with the target intersection on the narrow street route as a first target passing intersection;
A computer program characterized by functioning as:   The route cost of the narrow street route is calculated by referring to at least one of the number of right / left turns at the narrow street intersection, the number of crossings, and the intersection angle between the approach route and the exit route. A computer program described in 1.   The computer program according to claim 9 or 10, wherein the route cost of the narrow street route is calculated with reference to one-way data and / or temporary stop data. When the nearest road is a narrow street, the computer
Save the target passing intersection A connecting to the waypoint in the route from the departure point to the waypoint,
Save the target passing intersection B connecting to the waypoint in the route from the waypoint to the destination,
Means for setting the target passing intersection A as a second waypoint in the main route from the target passing intersection B to the destination;
It is made to function as, The computer program in any one of Claims 9-11 characterized by the above-mentioned.   The recording medium which records the computer program as described in any one of Claims 9-12.

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