Route search device

Abstract

To provide a route search device which searches for a route to a destination.SOLUTION: A route search device includes means which acquires map information that includes multiple roads. The route search device includes first decision means which decides a reference position and a destination on the map information. The route search device includes second decision means which decides a constraint condition when a movable body moves to the destination with the reference position as a starting point and including at least one of the upper limit value of the required time to the destination and the upper limit value of the distance to the destination. The route search device includes route search means that searches for a route from the reference position to the destination so as to satisfy the constraint condition. The route search means specifies a prescribed road being a road through which the movable body has passed or a road that has been selected as a route from the multiple roads. The route search means searches for the route so that such a percentage that the specified prescribed road is included in the route becomes low.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a route search device that searches for a route to a destination. [Background technology]

[0002] There are known techniques for searching for a route from a departure point to a destination using a map application on a smartphone or the like. These techniques can present a user with multiple route candidates calculated according to some general indices, such as the shortest travel distance, the shortest travel time, and the minimum number of transfers. The user can then select one route from the multiple candidates. For example, Patent Document 1 discloses a related technique. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-204416 A Summary of the Invention [Problem to be solved by the invention]

[0004] With technology such as that described in Patent Document 1, it is difficult to search for routes that deviate from the shortest route or the route with the shortest travel time. As a result, it is not possible to suggest to the user a travel behavior that would allow the user to reach a destination by visiting various points. [Means for solving the problem]

[0005] The route search device includes a means for acquiring map information including a plurality of roads. The route search device includes a first determination means for determining a reference position and a destination on the map information. The route search device includes a second determination means for determining a constraint condition when a mobile body moves from a reference position to the destination, the constraint condition including at least one of an upper limit of a time required to reach the destination or an upper limit of a distance to the destination. The route search device includes a route search means for searching a route from the reference position to the destination so as to satisfy the constraint condition. The route search means identifies, from among the plurality of roads, a predetermined road that is a road that the mobile body has passed through or that has been selected as a route. The route search means searches for a route so as to reduce a proportion of the identified predetermined road included in the route.

[0006] According to the above configuration, by using the past behavior history and route search history of the mobile object, the route can be optimized to allow detours under certain constraints. This makes it possible to encourage the mobile object to deviate from the shortest route or the route with the shortest travel time and to take a wandering action to reach the destination by visiting various points.

[0007] The route search means may search for a route based on an evaluation value based on entropy. Details of the effects will be described in the embodiments.

[0008] The map information may include a plurality of intersections. The route search device may further include means for storing a visit count for each of a plurality of intersections, which is an integrated number of times at least one of the number of times the mobile object has passed through the intersection or the number of times the intersection has been selected as a route. The route search means may search for a route from a reference position to a destination via N intersections by repeating a process of selecting a K+1th intersection N times using a Kth intersection as a reference. N may be a natural number of 1 or more, and K may be a natural number of 1 or more and N-1 or less. When selecting the K+1th intersection, the route search means may preferentially select an intersection with a low number of visits. Details of the effects will be described in the examples.

[0009] The route search means may select the (K+1)th intersection by heuristic search. The details of the effect will be described in the embodiment.

[0010] The system may further include a means for acquiring current position information of the mobile object. The first determination means may determine a current reference position based on the current position information. The second determination means may determine, as a constraint condition, a remaining time obtained by subtracting an elapsed time since the mobile object started moving toward the destination from an upper limit of the required time. The route search means may re-search for a route so that the destination can be reached within the remaining time. Details of the effects will be described in the examples.

[0011] The system may further include a means for acquiring current position information of the mobile body. The first determination means may determine a current reference position based on the current position information. The second determination means may determine, as a constraint condition, a remaining number of passes obtained by subtracting the number of intersections or roads that the mobile body has passed through since starting to move toward the destination from an upper limit of intersections or roads that can be passed through. The route search means may re-search for a route so that the destination can be reached within the remaining number of passes. Details of the effects will be described in the examples.

[0012] The present invention may further comprise a presentation means capable of presenting the route searched for by the route search means.

[0013] There may be a plurality of moving objects. The route search means may specify, as the predetermined road, a road that has been passed by any one of the plurality of moving objects, or a road that has been selected as a route by any one of the plurality of moving objects. Details of the effects will be described in the embodiments. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram of a route search device 1. [Diagram 2] FIG. 11 is a flow diagram illustrating a search process. [Diagram 3] FIG. 11 is a flowchart illustrating the specific process contents of step S40. [Figure 4] 1 is a graph structure GS for explaining a specific example of a search. [Diagram 5] 1 is a graph structure GS for explaining a specific example of a search. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0015] (Configuration of route search device 1) 1 shows a block diagram of a route search device 1. The route search device 1 can be configured, for example, by a PC (short for personal computer) equipped with a CPU, ROM, RAM, non-volatile storage device, etc., a tablet terminal, or a smartphone. The route search device 1 mainly includes a user interface unit 10, a map information acquisition unit 11, a destination determination unit 12, a constraint condition determination unit 13, a current position acquisition unit 14, a history storage unit 15, a route search unit 16, and a presentation unit 17. The CPU executes a program stored in the non-volatile storage device, so that the CPU functions as the map information acquisition unit 11 to the presentation unit 17, etc., shown in FIG. 1.

[0016] The user interface unit 10 is a part for receiving various inputs from the user and presenting various information to the user. The user interface unit 10 may include, for example, a touch panel, a keyboard, a speaker, a microphone, etc. The user interface unit 10 may also include an in-vehicle head-up display or a wearable visual display (e.g., a head-mounted display). The map information acquisition unit 11 is a part for acquiring map information. The map information is data including a plurality of roads and a plurality of intersections. The destination determination unit 12 is a part for determining a reference position and a destination on the map information. The reference position is a position that includes various concepts. For example, it may be a starting point or a current location.

[0017] The constraint condition determination unit 13 is a part that determines the constraint conditions when a moving body moves from a reference position as a starting point to a destination. The moving body is, for example, a user who owns the route search device 1, or a vehicle in which the route search device 1 is mounted. The constraint conditions are positions that include various concepts. For example, the constraint conditions may include at least one of an upper limit of the time required to reach the destination, or an upper limit of the distance to the destination. The distance to the destination includes various concepts. For example, it may be a straight-line distance or a road distance. In addition, the distance may be represented by the number of roads connecting the intersections, or the number of intersections to be passed through.

[0018] The current position acquisition unit 14 is a unit that acquires the current position information of the mobile object. The current position information may be acquired by a GPS provided in the current position acquisition unit 14, or may be acquired on map information. The history storage unit 15 is a unit that stores the number of visits for each of a plurality of intersections. The number of visits is a number obtained by accumulating at least one of the number of times the mobile object has passed through the intersection or the number of times the intersection has been selected as a route. The route search unit 16 is a unit that searches for a route from a reference position to a destination so as to satisfy a constraint condition. The specific processing content of the route search unit 16 will be described later. The presentation unit 17 is a unit that can present the route searched by the route search unit 16. There may be various methods for presenting the route. For example, a map image may be displayed on a display, or a voice guide may be used.

[0019] (Search contents of route search unit 16) The route search unit 16 searches for a route that allows a detour under certain constraints. To this end, it is equipped with a method for evaluating the novelty and variability of the generated route. The novelty of a route is the degree to which the route generated this time differs from routes the user has taken before or routes generated in the past. The variability of a route is the degree of difference between multiple routes when multiple routes are generated.

[0020] In this embodiment, the route search unit 16 evaluates the novelty and variability of a route based on a calculation formula for the migration entropy. Here, the network structure (road network) of the map information that is the target of the route search is represented as G=(V,E). Here, V represents a set of vertices, and E represents a set of edges. The vertices correspond to intersections, and the edges correspond to roads. In addition, the set of n travel routes that have been presented and traveled in the past is represented by the following formula.

number

[0021] The number of visits of previously visited vertices and edges is calculated and expressed as follows:

number

[0022] For a vertex, the normalized quantity is calculated as follows:

number

[0023] New route P n+1 The evaluation value based on the wandering entropy when presenting can be approximately calculated using the following formula.

number

[0024] (Example of a specific calculation method of the route search unit 16) The concept of the calculation method by which the route search unit 16 searches for a novel route will be described. That is, the route search unit 16 identifies roads that a mobile object has passed through or that have been selected as a route (predetermined roads) from among a plurality of roads included in the map information. Then, the route search unit 16 searches for a route such that the proportion of the predetermined roads included in the route is low.

[0025] A specific example of the calculation method by the route search unit 16 will be described. The assumptions of the calculation will be described. Only road network information is used. The constraint condition is the upper limit of the distance to the destination. Specifically, the upper limit of the distance is set to a constant multiple (1.3 to 2 times) of the shortest travel distance.

[0026] In order to achieve the optimization approximately, in this embodiment, a heuristic search is implemented. In the heuristic search, an evaluation function f(n) is used that lowers the priority of searching vertices and edges that have been passed through in the past. Here, the following formula (1) is used as the evaluation function f(n).

number

[0027] In this embodiment, the lower the calculated value of the evaluation function f(n), the higher the evaluation value (i.e., higher novelty and larger variance). Therefore, when γ is a positive value, the larger γ is set, the less likely a vertex with a high number of visits is to be selected. As a result, it becomes possible to search for a route with higher novelty and larger variance.

[0028] (Route search process contents) The search process executed by the route search device 1 will be described with reference to Fig. 2. The flow in Fig. 2 starts when a route search instruction is input to the route search device 1. In step S10, the map information acquisition unit 11 acquires map information. There may be various methods for acquiring the map information. For example, the map information may be received from an external server by a communication means (not shown).

[0029] In step S20, the destination determination unit 12 determines a reference position and a destination. There may be various methods for determining the reference position and the destination. For example, they may be determined by receiving an input from a user through the user interface unit 10. In step S30, the constraint condition determination unit 13 determines a constraint condition. There may be various methods for determining the constraint condition. For example, they may be determined by receiving an input from a user through the user interface unit 10.

[0030] In step S40, the route search unit 16 searches for a route from the reference position to the destination so as to satisfy the constraint conditions. Specifically, the K+1th intersection is selected by heuristic search with the Kth intersection as a reference. In this selection, an intersection that has been visited less frequently is preferentially selected. By repeating this selection process N times, it is possible to search for a route from the reference position to the destination via N intersections. Here, N is a natural number equal to or greater than 1, and K is a natural number equal to or greater than 1 and equal to or less than N-1.

[0031] The specific processing content of step S40 will be described with reference to the subroutine in Fig. 3. In step S41, the route search unit 16 assigns an index to each of a plurality of intersections included in the map information. The index is a series of unique and equal-value integers for identifying each intersection. Note that if an index is assigned to each intersection in advance, this step may be omitted.

[0032] In step S42, the route search unit 16 selects the first intersection to move from the start point s. A specific description will be given. The route search unit 16 picks up all intersections (candidate points) that can be moved to. In addition, the number of visits to all candidate points is read from the history storage unit 15. Next, an evaluation function f(n) is calculated for all candidate points to calculate evaluation values. Then, the candidate point with the best (i.e., smallest) evaluation value is determined as the next reference position. Note that, if there are multiple candidate points with the best evaluation value, any one of the candidate points is selected based on a predetermined rule. In this embodiment, the predetermined rule is to select the candidate point with the smallest index. In step S43, the history storage unit 15 increments the number of visits to the intersection selected in step S42 by one.

[0033] In step S44, the route search unit 16 selects the next intersection to move to from the reference position. The specific processing content is the same as that of step S42, so the description will be omitted. In step S45, the history storage unit 15 counts up by one the number of visits to the intersection selected in step S44.

[0034] In step S46, the route search unit 16 judges whether or not the destination t has been reached. If the judgment is negative (S46: NO), the process returns to step S44 and loop processing is executed. On the other hand, if the judgment is positive (S46: YES), it is judged that one route has been completed, and the process proceeds to step S47.

[0035] In step S47, the route search unit 16 judges whether or not to create the next route. This judgment may be made, for example, based on whether or not a predetermined number of routes have been created. If the judgment is affirmative (S47: YES), the process returns to step S42, and creation of the next route is started. On the other hand, if the judgment is negative (S47: NO), the process is judged to have ended the route search, and the process proceeds to step S50 (FIG. 2).

[0036] In step S50, the presentation unit 17 presents the searched route to the user via the user interface unit 10. At this time, a plurality of routes may be presented and the user may select one of the routes. In step S60, the presentation unit 17 guides the user along the route. In step S70, the history storage unit 15 increments by one the number of visits to the intersection that the user has passed through.

[0037] In step S75, it is determined whether or not the destination has been reached. If the determination is affirmative (S75: YES), the flow ends, and if the determination is negative (S75: NO), the process proceeds to S80. In step S80, it is determined whether or not to perform a route re-search. This determination may be made, for example, when a predetermined time has elapsed since the previous route search. If the determination is negative (S80: NO), the process returns to S75, and if the determination is affirmative (S80: YES), the process proceeds to S90.

[0038] In step S90, the current position acquisition unit 14 acquires the current position. The destination determination unit 12 sets the acquired current position as a reference position. In step S100, the constraint condition determination unit 13 updates the constraint condition. Specifically, the remaining time is calculated. The remaining time is a time obtained by subtracting the elapsed time since the moving body started moving toward the destination from the upper limit of the required time. Then, the remaining time is determined as the constraint condition. Returning to step S40, the route search unit 16 searches again for a route so as to arrive at the destination within the remaining time. After that, a loop process is performed.

[0039] (Example of exploration) A specific example of a search will be described using a graph structure GS as shown in FIG. 4 as an example. In this specific example, a travel route from a start point s to a destination point t is searched for on the graph structure GS. In addition, a case will be described in which an evaluation function f(n) shown in formula (1) is used, with α=-1, β=0, and γ=1e-12. In addition, a case will be described in which an index of "0" is assigned to the start point s, "1-5" to the intersections C1-C5, and "6" to the destination t in step S41. In addition, a case will be described in which the constraint condition is the distance to the destination, and "the number of roads that can be taken connecting the intersections is 5 or less."

[0040] A case where the first route is searched will be described. The first search is started with the start point s as the reference position. In step S42 (FIG. 3), the visit counts of all intersections are read from the history storage unit 15. In this embodiment, the case where the read visit counts are "1, 1, 1, 0, 1" for the intersections C1-C5 in that order will be described. Also, the case where the visit counts of the start point s and the destination t are "1, 1" will be described. In FIG. 4, the visit counts are indicated by numbers enclosed in squares. Also, intersections that can be reached (i.e., intersections directly connected by roads) are picked up as candidate points. In this example, the candidate points are intersections C1 and C2. Then, based on the formula (A), the evaluation function f(1)=-1+γ of the intersection C1 and the evaluation function f(2)=-1+γ of the intersection C2 are calculated. Since the evaluation values ​​are equal, the intersection C1 with the smaller index is selected (see arrow A1). Then, the visit count of the intersection C1 is counted up by one (step S43, FIG. 5).

[0041] A second search is started with intersection C1 (current location information) as the reference position. The number of roads that can be taken via is four (constraint condition). In step S44, intersections C3 and C4 become candidate points. Then, based on the formula (A), evaluation functions f(3)=-2+γ, f(4)=-2 are calculated. Intersection C4 having the smallest evaluation value is selected (see arrow A2). Then, the number of visits to intersection C4 is counted up by one (step S43, FIG. 5).

[0042] The third search is started with intersection C4 (current location information) as the reference position. There are three remaining roads that can be taken via (constraint condition). In step S44, intersection C3 and destination t become candidate points. Then, based on equation (A), evaluation functions f(3)=-3+γ and f(t)=-3+γ are calculated. Since the evaluation values ​​are equal, intersection C3 with the smaller index is selected (see arrow A3). Then, the number of visits to intersection C3 is counted up by one (step S43, FIG. 5).

[0043] The fourth search is started with intersection C3 (current location information) as the reference position. There are two roads remaining that can be taken via (constraint condition). In step S44, intersections C2 and C5 become candidate points. However, proceeding to intersection C2 would result in six or more roads to be taken via before reaching destination t, which would not satisfy the constraint condition. Therefore, the search for intersection C2 is pruned. As a result, intersection C5 is selected (see arrow A4). Then, the number of visits to intersection C5 is incremented by one (step S43, FIG. 5).

[0044] The fifth search is started with intersection C5 (current location information) as the reference position. There is only one road remaining that can be taken via (constraint condition). In step S44, intersection C2 and destination t become candidate points. However, proceeding to intersection C2 would not satisfy the constraint condition, so the search for intersection C2 is pruned. Thus, destination t is selected (see arrow A5). As a result, a first route is generated that travels from start point s to destination t via intersections C1, C4, C3, and C5. Also, the number of visits to each intersection is updated, as shown in FIG. 5.

[0045] The second route is generated based on the graph structure GS (FIG. 5) in which the visit count was updated when the first route was generated. The specific route generation method is similar to the first route generation method, so the explanation is omitted. After that, multiple routes can be generated by repeating the above-mentioned route generation process.

[0046] In conventional route search technology, it was difficult to search for a route that deviates from indicators such as the shortest travel distance, the shortest travel time, and the minimum number of transfers. On the other hand, in the technology of this specification, by using the user's past behavior history and route search history, it is possible to optimize the route so that a detour is allowed within certain constraints. This makes it possible to encourage the user to deviate from the shortest route or the route with the shortest travel time and to visit various points while reaching the destination. Therefore, it is possible to support the search for a travel route in a situation where the user is looking for an "exciting travel behavior" or a situation where the user wants to "travel around a certain area during free time". This makes it possible to have a positive psychological effect on the user, for example, by allowing the user to perform "travel behavior in an unfamiliar town visited during a trip or business trip" or "travel behavior that allows new discoveries and experiences in a town that is usually visited". EXAMPLES

[0047] In the first embodiment, an approximation calculation method of the wandering entropy based on the number of visits to the vertices has been described as a method for evaluating the novelty and variability of the route. In the second embodiment, another evaluation method will be described.

[0048] Let us explain the background conditions. Let G = (V, E) denote a graph structure. Let P be a path from a starting point s to a destination t. i Specifically, the sequence of vertices passed through is expressed as P i = <v1=s,v2,v3,...,v l =t> or a sequence P of pairs of vertices and passing times i In addition, assume that the K routes used so far have already been calculated as shown in the formula below.

number

[0049] As a first method for evaluating the novelty of a route, a method for calculating the migration entropy based on the results of a histogram calculation using GPS location information and stay time may be used. The specific details are known, so a description thereof will be omitted here.

[0050] As a second method for evaluating the novelty of a route, the novelty as a set may be calculated. For example, the novelty may be determined to be high when the following relationship is satisfied:

number

[0051] A third method for evaluating the novelty of a path may be to perform a calculation based on the evaluation of set and sequence similarity. i and route P j The similarity as a path of sim ij For example, the novelty may be calculated using the edit distance when the vertex sequence is a character string, the longest common sequence, or a sequence similarity such as DTW using latitude and longitude and Euclidean distance. For example, the novelty may be evaluated based on the following formula:

number

[0052] Although the embodiments of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above.

[0053] (Modification) There may be a plurality of users. A group may be formed by the plurality of users. In this case, in the concept of the above-mentioned search method, a road that any one of the plurality of users has passed through, or a road that any one of the users has selected as a route, may be specified as the predetermined road. More specifically, in the term f3 of the formula (1), "the number of times that any one of the group of multiple users has passed through" may be used. This makes it possible to encourage the group of multiple users to roam.

[0054] The technical elements described in this specification or drawings have technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful.

[0055] The destination determination unit 12 is an example of a first determination means, and the constraint condition determination unit 13 is an example of a second determination means.

[0056] Aspects of the present technology are listed below. [Aspect 1] A means for acquiring map information including a plurality of roads; A first determination means for determining a reference position and a destination on the map information; a second determination means for determining a constraint condition when a moving body moves from the reference position as a starting point to the destination, the constraint condition including at least one of an upper limit of a time required to reach the destination or an upper limit of a distance to the destination; a route search means for searching for a route from the reference position to the destination so as to satisfy the constraint condition; Equipped with The route search means Identifying a predetermined road from among the plurality of roads, the predetermined road being a road that the moving body has passed through or a road that has been selected as part of the route; searching for the route so that the ratio of the specified road included in the route is low; Route finding device. [Aspect 2] 2. The route search device according to aspect 1, wherein the route search means searches for the route based on an evaluation value that is based on entropy. [Aspect 3] The map information includes a plurality of intersections, The route search device further includes a means for storing a visit count for each of the plurality of intersections, the visit count being an integrated total of at least one of a number of times the mobile body has passed through the intersection or a number of times the intersection has been selected as part of the route; the route search means searches for the route from the reference position to the destination via N intersections by repeating a process of selecting a (K+1)th intersection using a Kth intersection as a reference N times, where N is a natural number equal to or greater than 1, and K is a natural number equal to or greater than 1 (N-1), 3. The route search device according to aspect 1 or 2, wherein, when selecting the K+1th intersection, the route search means preferentially selects an intersection that has been visited less frequently. [Aspect 4] 4. The route search device according to aspect 3, wherein the route search means selects the K+1-th intersection by heuristic search. [Aspect 5] The mobile unit further includes a means for acquiring current location information of the mobile unit. The first determination means determines the current reference position based on the current position information, the second determination means determines, as the constraint condition, a remaining time obtained by subtracting an elapsed time since the moving body started moving toward the destination from an upper limit value of the required time; The route search device according to any one of aspects 1 to 4, wherein the route search means re-searches for the route so as to arrive at the destination within the remaining time. [Aspect 6] The mobile unit further includes a means for acquiring current location information of the mobile unit. The first determination means determines the current reference position based on the current position information, the second determination means determines, as the constraint condition, a remaining number of passes obtained by subtracting the number of intersections or roads that the moving body has passed through since starting to move toward the destination from an upper limit of the number of intersections or roads that the moving body can pass through; The route search device according to any one of aspects 1 to 4, wherein the route search means re-searches for the route so that the destination can be reached within the remaining number of stops. [Aspect 7] The presenting means may further include a presenting means capable of presenting the route searched by the route searching means. 7. A route search device according to any one of aspects 1 to 6. [Aspect 8] There are a plurality of the moving bodies, A route search device according to any one of aspects 1 to 7, wherein the route search means identifies, as the specified road, a road that has been passed by any one of the plurality of moving bodies, or a road that has been selected as the route by any one of the plurality of moving bodies. [Explanation of symbols]

[0057] 1: Route search device 10: User interface unit 11: Map information acquisition unit 12: Destination determination unit 13: Constraint condition determination unit 14: Position acquisition unit 15: History storage unit 16: Route search unit 17: Presentation unit

Claims

1. A means for acquiring map information including a plurality of roads and a plurality of intersections; a first determination means for determining a reference position and a destination on the map information; a second determination means for determining a constraint condition when a moving body moves from the reference position as a starting point to the destination, the constraint condition including at least one of an upper limit of a time required to reach the destination and an upper limit of a distance to the destination; a route search means for searching for a route from the reference position to the destination so as to satisfy the constraint condition; a means for storing a visit count for each of the plurality of intersections, the visit count being calculated by accumulating at least one of the number of times the mobile object has passed through the intersection and the number of times the intersection has been selected as part of the route; Equipped with the route search means searches for the route from the reference position to the destination via N intersections by repeating a process of selecting a (K+1)th intersection by heuristic search N times using a Kth intersection as a reference, where N is a natural number equal to or greater than 1 and K is a natural number equal to or greater than 1 (N-1); When selecting the (K+1)th intersection, the route search means preferentially selects an intersection that has been visited less frequently. Route finding device.

2. A means for acquiring map information including a plurality of roads; A means for acquiring current location information of a mobile object; a first determination means for determining a current reference position and a destination on the map information based on the current position information; a second determination means for determining a constraint condition when the moving body moves from the reference position as a starting point to the destination, the second determination means determining, as the constraint condition, a remaining time obtained by subtracting an elapsed time from when the moving body started moving toward the destination from an upper limit value of a required time to the destination; a route search means for searching for a route from the reference position to the destination so as to satisfy the constraint condition; Equipped with The route search means Identifying a predetermined road from among the plurality of roads, the predetermined road being a road that the moving body has passed through or a road that has been selected as part of the route; Searching for the route so that the ratio of the specified road included in the route is low; re-searching the route so as to arrive at the destination within the remaining time; Route finding device.

3. A means for acquiring map information including a plurality of roads; A means for acquiring current location information of a mobile object; a first determination means for determining a current reference position and a destination on the map information based on the current position information; a second determination means for determining a constraint condition when the moving body moves from the reference position as a starting point to the destination, the second determination means determining, as the constraint condition, a remaining number of passes obtained by subtracting the number of intersections or roads that the moving body has passed through since starting to move toward the destination from an upper limit of the number of intersections or roads that the moving body can pass through; a route search means for searching for a route from the reference position to the destination so as to satisfy the constraint condition; Equipped with The route search means Identifying a predetermined road from among the plurality of roads, the predetermined road being a road that the moving body has passed through or a road that has been selected as part of the route; Searching for the route so that the ratio of the specified road included in the route is low; re-searching the route so as to arrive at the destination within the remaining number of stops; Route finding device.

4. 4. The route search device according to claim 1, further comprising a presentation means capable of presenting the route searched for by the route search means.

5. There are a plurality of the moving bodies, 4. The route search device according to claim 2, wherein the route search means identifies, as the predetermined road, a road that has been passed by any one of the plurality of moving bodies or a road that has been selected as the route by any one of the plurality of moving bodies.

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