Patent Publication Number: US-9903725-B2

Title: Route searching system, route searching method, and computer program

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage of International Application No. PCT/JP2015/051023, filed on Jan. 16, 2015, which claims priority from Japanese Patent Application No. 2014-012853, filed on Jan. 27, 2014, the contents of all of which are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a route searching system, a route searching method, and a computer program for searching for a recommended route including an automated driving section where automated driving control of a vehicle is performed. 
     BACKGROUND ART 
     In recent years, there are many vehicles equipped with navigation devices configured to provide travel guidance of the vehicles for drivers to be able to easily reach desired destinations. Herein, such a navigation device is a device that can detect the current position of a vehicle equipped therewith by a GPS receiver, for example, and can acquire map data corresponding to the current position from a recording medium such as a DVD-ROM or a HDD or through a network to display the map data on a liquid crystal monitor. Furthermore, this navigation device has a route search function of searching for a recommended route from the current vehicle position to a desired destination when the desired destination is input. The navigation device sets a recommended route thus found as a guidance route, displays the guidance route on a display screen, and also provides audio guidance when, for example, the vehicle approaches an intersection, thereby reliably guiding a user to the desired destination. In recent years, some of mobile phones, smart phones, tablet terminals, and personal computers, for example, have the same functions as that of the navigation device. 
     In recent years, as a traveling mode of a vehicle, other than manual traveling in which a vehicle travels based on driving operation of a user, traveling by automated driving control has been newly proposed that causes the vehicle to travel in an automated way along a preset route without driving operation of the user. In the automated driving control, for example, the current position of the vehicle, the lane in which the vehicle is traveling, and the positions of other vehicles there around are detected at any time, and vehicle control of the steering, the drive source, and the brake, for example, is automatically performed such that the vehicle travels along the preset route. Although traveling by the automated driving control can advantageously reduce the driving burden on a user, there are situations in which road conditions make it difficult to cause the vehicle to travel by the automated driving control. For example, there are situations in which the vehicle needs to change lanes or merge into another lane in a short section or travel in bad weather. In such situations, the vehicle needs to interrupt traveling by the automated driving control and shift to manual driving. 
     In view of this, the navigation device described above, for example, is newly required to search for a recommended route in consideration of interruption of the automated driving control described above. For example, in order to cause a vehicle to travel by automated driving control without being interrupted, Patent Document 1 proposes a technique of classifying a road having low accuracy of the current position detected by the GPS as an automated-control inapplicable road on which the vehicle cannot travel by the automated driving control, and searching for a route avoiding the automated-control inapplicable road. 
     RELATED-ART DOCUMENTS 
     Patent Documents 
     
         
         [Patent Document 1] Japanese Patent Application Publication No. 2011-118603 (JP 2011-118603 A) (pages 6 to 7, FIG. 4) 
       
    
     SUMMARY 
     However, in the technique described in Patent Document 1, because a route is searched for such that roads classified as automated-control inapplicable roads are not included, the vehicle can travel by the automated driving control without being interrupted, but situations occur in which a very long roundabout route is searched for and any route cannot be searched for in some cases. 
     The present disclosure has been made to solve conventional problems described above, and an object thereof is to provide a route searching system, a route searching method, and computer program that make it possible to select an appropriate recommended route for a user in consideration of interruption of automated driving control. 
     A first route searching system, a route searching method, and a computer program according to the present disclosure for achieving the object are a route searching system that searches for a recommended route from a departure point to a destination including an automated driving section where automated driving control of a vehicle is performed, a route searching method for performing route search using the system, and a computer program that causes the system to perform the respective functions below. Specifically, the system includes: route candidate acquisition code for acquiring a plurality of candidate routes that are candidates for the recommended route; interruption section specifying code for, for each of the candidate routes acquired by the route candidate acquisition code, specifying an interruption section where automated driving control is interrupted in the automated driving section included in the candidate route; interruption information acquisition code for, based on the interruption section specified by the interruption section specifying code, for each of the candidate routes, acquiring interruption information indicating that the automated driving control is interrupted in the automated driving section included in the candidate route; and recommended-route selecting code for selecting the recommended route including the interruption section from among the candidate routes, based on the interruption information acquired by the interruption information acquisition code. 
     A second route searching system, a route searching method, and a computer program according to the present disclosure are a route searching system that searches for a recommended route from a departure point to a destination including an automated driving section where automated driving control of a vehicle is performed, a route searching method for performing route search using the system, and a computer program that causes the system to perform the respective functions below. Specifically, the system includes: route candidate acquisition code for acquiring a plurality of candidate routes that are candidates for the recommended route; interruption-predicted section specifying code for, for each of the candidate routes acquired by the route candidate acquisition code, specifying an interruption-predicted section where there is a possibility that automated driving control will be interrupted in the automated driving section included in the candidate route; interruption-predicting information acquisition code for, based on the interruption-predicted section specified by the interruption-predicted section specifying code, for each of the candidate routes, acquiring interruption-predicting information indicating that the automated driving control is predicted to be interrupted in the automated driving section included in the candidate route; and recommended-route selecting code for selecting the recommended route including the interruption-predicted section from among the candidate routes, based on the interruption-predicting information acquired by the interruption-predicting information acquisition code. 
     With the first route searching system, the route searching method, and the computer program according to the present disclosure having the structure described above, when a route to a destination is searched for, a recommended route can be selected in consideration of an interruption section where automated driving control is interrupted. By using interruption information on interruption of the automated driving control, while preventing the occurrence of a situation in which an excessively long roundabout route is found or no route is found, it is possible to select a more appropriate recommended route for the user. 
     With the second route searching system, the route searching method, and the computer program according to the second aspect of the present disclosure, when a route to a destination is searched for, a recommended route can be selected in consideration of an interruption-predicted section where there is a possibility that the automated driving control will be interrupted. By using interruption-predicting information on interruption prediction of the automated driving control, while preventing the occurrence of a situation in which an excessively long roundabout route is found or no route is found, it is possible to select a more appropriate recommended route for the user. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a structure of a navigation device according to a first embodiment. 
         FIG. 2  is a flowchart of a route-search processing program according to the first embodiment. 
         FIG. 3  is a figure illustrating an example of correspondence between additional values α and reasons for the interruption of automated driving control. 
         FIG. 4  is a diagram illustrating a route guidance screen providing guidance for a recommended route displayed on a liquid crystal display. 
         FIG. 5  is a diagram illustrating the route guidance screen providing guidance for a candidate route other than the recommended route displayed on the liquid crystal display. 
         FIG. 6  is a diagram illustrating an example of control contents of the automated driving control that are set for a planned traveling route of a vehicle. 
         FIG. 7  is a flowchart of a sub-processing program of interruption-section coupling processing. 
         FIG. 8  is an explanatory diagram for explaining coupling of interruption sections. 
         FIG. 9  is a flowchart of an automated-driving-control processing program according to the first embodiment. 
         FIG. 10  is a flowchart of a sub-processing program of interruption-section detection processing. 
         FIG. 11  is a figure illustrating an example of correspondence between additional values α and probabilities that the automated driving control will be interrupted. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A route searching system according to the present disclosure will now be described with reference to the drawings on the basis of a first embodiment and a second embodiment implemented in a navigation device. 
     First Embodiment 
     Referring to  FIG. 1 , a schematic structure of a navigation device  1  according to the first embodiment will be described first.  FIG. 1  is a block diagram illustrating the navigation device  1  according to the first embodiment. 
     As depicted in  FIG. 1 , the navigation device  1  according to the first embodiment includes: a current-position detecting unit  11  that detects the current position of a vehicle equipped with the navigation device  1 ; a data recording unit  12  in which various types of data are recorded; a navigation electronic control unit (ECU)  13  that performs various types of arithmetic processing on the basis of input information; an operating unit  14  that receives operation from a user; a liquid crystal display  15  that displays a map around the vehicle, information on a route found by a later-described route search processing to the user, and other items; a speaker  16  that outputs audio guidance about route guidance; a DVD drive  17  that reads a DVD as a recording medium; and a communication module  18  that communicates with information centers such as a probe center and a Vehicle Information and Communication System (VICS, registered trademark) Center. The navigation device  1  is connected to a vehicle exterior camera  19  that is mounted on the vehicle equipped with the navigation device  1  and various sensors through an in-vehicle network such as a CAN. Furthermore, the navigation device  1  is connected to a vehicle control ECU  20  that performs various controls on the vehicle equipped with the navigation device  1  in a manner capable of bidirectional communication. The navigation device  1  is also connected to various operation buttons  21  installed in the vehicle, such as an automated driving switch and an automated driving start button described later. 
     The following describes the respective components constituting the navigation device  1  in order. The current-position detecting unit  11  includes a GPS  22 , a vehicle speed sensor  23 , a steering sensor  24 , and a gyroscopic sensor  25 , and can detect the current position and the orientation of the vehicle, the traveling speed of the vehicle, and the current time, for example. In particular, the vehicle speed sensor  23 , which is a sensor for detecting the travel distance of the vehicle and the vehicle speed, generates pulses depending on the rotation of drive wheels of the vehicle, and outputs pulse signals to the navigation ECU  13 . The navigation ECU  13  counts the generated pulses to calculate the rotation speed of the drive wheels and the travel distance. Herein, the navigation device  1  does not have to include all of four types of the sensors described above, and the navigation device  1  may include only one or some of these sensors. 
     The data recording unit  12  includes a hard disk (not depicted) as an external storage and a recording medium and a recording head (not depicted). The recording head is a driver for reading map information DB  31  and a predetermined program, for example, stored in the hard disk and writing predetermined data in the hard disk. Herein, the data recording unit  12  may include an optical disk such as a memory card, a CD, or a DVD instead of the hard disk. The map information DB  31  may be stored in an external server, and the navigation device  1  may be configured to acquire the map information DB  31  through communication. 
     The map information DB  31  is a storage device for storing, for example, link data  33  on roads (links), node data  34  on node points, search data  35  used for processing related to search and change of a route, facility data on facilities, map display data for displaying a map, intersection data on respective intersections, and search data for searching for locations. 
     Examples of data each recorded as the link data  33  include: data on the respective links constituting roads representing widths, slopes, cants, and banks of the roads, conditions of road surfaces, merging sections, the number of lanes of the roads, locations where the number of lanes decreases, locations where the roads narrow, and railroad crossings, for example; data on corners representing curvature radii, intersections, T-junctions, and entrances and exits of the corners, for example; data on road attributes representing downhill roads and uphill roads, for example; data on road types representing ordinary roads such as a national highway, a prefectural road, and a narrow street and toll roads such as a national expressway, an urban expressway, a motor highway, an ordinary toll road, and a toll bridge, for example. 
     As the node data  34 , for example, pieces of data are recorded that relate to: coordinates (locations) of a node point set for each actual road junction (including an intersection and a T-junction) and set for each road at each distance determined based on curvature radii, for example; a node attribute representing whether the node is a node corresponding to an intersection; a connection link number list that is a list of link numbers of links connected to the node; an adjacent node number list that is a list of node numbers of the nodes adjacent to the node through the links; and data regarding the height (altitude) and other properties of each node, for example. 
     As the search data  35 , various types of data are recorded that are used for route search processing in which a route from a departure point (e.g., the current position of the vehicle) to a destination is searched for as described later. Specifically, cost calculation data is stored that is used for calculating a search cost. The search cost means a cost representing the numerical level of appropriateness of an intersection as part of a route (hereinafter, called “intersection cost”) and a cost representing the numerical level of appropriateness of a link in a road as part of a route (hereinafter, called “link cost”), for example. Note that, in the first embodiment, a recommended route is searched for by using a required time from the departure point to the destination as described later, and therefore various types of data for calculating a required time for the route is also stored in the search data  35 . Herein, the search cost may be defined by the required time. 
     In the navigation device  1  according to the first embodiment, particularly when a recommended route from the departure point to the destination including an automated driving section where automated driving control of the vehicle is performed is searched for, the recommended route is searched for based on interruption information indicating that the automated driving control is interrupted in the automated driving section. Specifically, when an interruption section where the automated driving control is interrupted is included, additional values corresponding to the numbers of times, durations, distances, and locations of the interruption of the automated driving control and the reasons for the interruption are added to the required times described above, and the resulting required times containing the additional values are compared to each other, whereby the recommended route is searched for. 
     As a traveling mode of the vehicle, in addition to traveling by manual driving in which the vehicle travels based on driving operation of the user, traveling by the automated driving control is available that causes the vehicle to travel in an automated way along a preset route without driving operation of the user. In the automated driving control, for example, the current position of the vehicle, the lane in which the vehicle is traveling, and the positions of other vehicles therearound are detected at any time, and vehicle control of the steering, the drive source, and the brake, for example, is automatically performed by the vehicle control ECU  20  such that the vehicle travels along the route preset. Details of the automated driving control are already publicly known, and thus description thereof is omitted. The automated driving control may be performed in all road sections. However, the following description is made assuming that, as an automated driving section where the automated driving control of the vehicle is performed, an expressway is set that is provided with gates (it does not matter whether the gate is manned or unmanned, or whether it is toll-free or charged) at boundaries between the expressway and other roads connected thereto, and the automated driving control is basically performed only when the vehicle is traveling in the automated driving section. Note that another section may be set as the automated driving section. For example, a national expressway, an urban expressway, a motor highway, a toll road, and an ordinary road may be set as the automated driving section. When the vehicle travels in the automated driving section, the automated driving control is not always performed, and the automated driving control is selected to be performed by the user and is performed only in situations appropriate for the vehicle to travel by the automated driving control as described later. In other words, the automated driving section is a section where the vehicle is allowed to perform the automated driving control in addition to the manual driving. 
     Although traveling by the automated driving control can advantageously reduce the driving burden on the user, there are situations in which road conditions make it difficult to cause the vehicle to travel by the automated driving control. In the navigation device  1  according to the first embodiment, sections where such situations occur in which it is difficult for the vehicle to perform the automated driving control in the automated driving section are set as interruption sections where the automated driving control of the vehicle is interrupted to cause the vehicle to travel by the manual driving. The setting of the interruption sections is basically performed during route search, and is also performed when the vehicle is traveling after the route search. For example, when a section where lane markings ahead of the vehicle in the traveling direction are faint is newly detected or a section where the weather has quickly become worse is newly detected, it is difficult to perform the automated driving control in this section, and thus this section is newly set as an interruption section. Details of the setting of the interruption sections and route search based on the set interruption sections are described later. 
     The navigation ECU  13 , which is an electronic control unit that performs overall control of the navigation device  1 , includes a CPU  41  serving as an arithmetic unit and a control unit, and also includes internal storages such as: a RAM  42  that is used as a working memory when the CPU  41  performs various types of arithmetic processing and that stores route data, for example, when a route is searched for; a ROM  43  that stores a route-search processing program (see  FIG. 2 ) and an automated-driving-control processing program (see  FIG. 9 ) described later, for example, in addition to control programs; and a flash memory  44  that stores programs read from the ROM  43 . The navigation ECU  13  configures various types of code as processing algorithms. For example, the route candidate acquisition code acquires a plurality of candidate routes that are candidates for the recommended route. The interruption section specifying code, for each of the candidate routes acquired by the route candidate acquisition code, specifies an interruption section where the automated driving control is interrupted in the automated driving section included in the candidate route. The interruption information acquisition code, based on the interruption section specified by the interruption section specifying code, for each of the candidate routes, acquires interruption information indicating that the automated driving control is interrupted in the automated driving section included in the candidate route. The recommended-route selecting code selects the recommended route including the interruption section from among the candidate routes on the basis of the interruption information acquired by the interruption information acquisition code. 
     The operating unit  14  is operated when a departure point as a travel start point and a destination as a travel end point are input, for example, and includes a plurality of operation switches (not depicted) such as various keys and buttons. The navigation ECU  13 , based on switch signals output by depressing the respective switches, for example, performs the various corresponding controls. The operating unit  14  may be alternatively structured with a touch panel provided on a front surface of the liquid crystal display  15 . The operating unit  14  may be also structured with a microphone and a voice recognition device. 
     The liquid crystal display  15  displays a map image including roads, traffic information, operation guidance, an operation menu, guidance for keys, candidates for a recommended route from the departure point to the destination that are found during route search, various types of information on the candidates for the recommended route, guidance information along a guidance route, news, weather forecasts, time, mail, and television programs, for example. Instead of the liquid crystal display  15 , a HUD or a HMD may be used. 
     The speaker  16  outputs audio guidance providing guidance for traveling along the guidance route based on instructions from the navigation ECU  13  and guidance about traffic information. 
     The DVD drive  17  is a drive that can read data stored in a recording medium such as a DVD or a CD. Based on the read data, music or video is replayed and the map information DB  31  is updated, for example. 
     The communication module  18  is a communication device for receiving traffic information, probe information, and weather information, for example, transmitted from traffic information centers such as a VICS center and a probe center, and examples of the communication module  18  include a mobile phone and a DCM. The examples also include a vehicle-to-vehicle communication device that communicates between vehicles and a road-to-vehicle communication device that communicates between a roadside unit and a vehicle. 
     The vehicle exterior camera  19  is structured with a camera using a solid-state image sensing device such as a CCD, and is attached above a front bumper of the vehicle and is disposed with its optical axis directed downward by a predetermined angle from the horizontal plane. The vehicle exterior camera  19  captures images of a scene ahead of the vehicle in the traveling direction when the vehicle travels in the automated driving section. The vehicle control ECU  20  detects lane markings painted on a road on which the vehicle travels and detects other vehicles therearound, for example, by performing image processing on the captured images, and performs the automated driving control of the vehicle on the basis of the detection result. Meanwhile, the navigation ECU  13  detects a section (e.g., a section where lane markings are faint) where a situation occurs in which it is difficult for the vehicle to perform the automated driving control on the basis of the captured images captured by the vehicle exterior camera  19  as described later when the vehicle travels in the automated driving section. The section thus detected is newly set as an interruption section as described later. The vehicle exterior camera  19  may be disposed on the rear or the side of the vehicle other than the front thereof. To detect a section where a situation occurs in which it is difficult for the vehicle to travel by the automated driving control, instead of the vehicle exterior camera  19 , various sensors such as an illuminance sensor and a rain sensor may be used. In this case, for example, heavy rain or dense fog can be detected. As means for detecting other vehicles, instead of the camera, a sensor such as a millimeter wave radar, vehicle-to-vehicle communication, or road-to-vehicle communication may be used. 
     The vehicle control ECU  20  is an electronic control unit that controls the vehicle equipped with the navigation device  1 . The vehicle control ECU  20  is connected to various drive units of the vehicle, such as a steering, a brake, and an accelerator. In the first embodiment, particularly when the vehicle travels in the automated driving section, the vehicle control ECU  20  controls the various drive units to perform the automated driving control of the vehicle. The navigation ECU  13  transmits an instruction signal related to the automated driving control to the vehicle control ECU  20  through the CAN at the time when a planned traveling route (guidance route) of the vehicle has been determined. The vehicle control ECU  20  then performs the automated driving control after the start of traveling in accordance with the received instruction signal. The contents of the instruction signal are information specifying the planned traveling route (guidance route) and information on control contents (e.g., going straight, changing lanes to the right, merging) of the automated driving control performed on the vehicle that are set for sections in the automated driving section included in the planned traveling route from which interruption sections are excluded. 
     The following describes the route-search processing program that the CPU  41  executes in the navigation device  1  according the first embodiment having the structure described above with reference to  FIG. 2 .  FIG. 2  is a flowchart of the route-search processing program according to the first embodiment. This route-search processing program, which is executed when predetermined operation for performing route search is received in the navigation device  1 , is a program for searching for a recommended route from a departure point to a destination. Programs illustrated by the flowcharts in  FIG. 2 ,  FIG. 7 ,  FIG. 9 , and  FIG. 10  are stored in the RAM  42  and the ROM  43  included in the navigation device  1 , and are executed by the CPU  41 . 
     To begin with, in the route-search processing program, at step (hereinafter, abbreviated as “S”)  1 , the CPU  41  determines whether the automated driving switch is ON. This automated driving switch is a switch that allows the user to switch between causing the vehicle to basically perform the automated driving control in the automated driving section and causing the vehicle to perform the manual driving without performing the automated driving control, and is disposed on an instrument panel, for example. 
     If it is determined that the automated driving switch is ON (YES at S 1 ), the process proceeds to S 3 . If it is determined that the automated driving switch is OFF (NO at S 1 ), the process proceeds to S 2 . 
     Specifically, when it has been determined that the automated driving switch is ON, the user wants the automated driving control to be performed in the automated driving section. Thus, at and after S 3  described later, the CPU  41  assumes that the vehicle basically performs the automated driving control in the automated driving section, and searches for a recommended route from the departure point to the destination. 
     In contrast, when it has been determined that the automated driving switch is OFF, the user wants the manual driving to be performed in the automated driving section without performing the automated driving control. Thus, at S 2 , the CPU  41  assumes that the vehicle performs the manual driving in the automated driving section, and searches for a recommended route from the departure point to the destination. Herein, the search processing for a recommended route at S 2  is the same as normal route search processing in which the automated driving control is not considered, and thus description thereof is omitted. When the route search processing is performed, guidance for a recommended route and the other candidate routes other than the recommended route (e.g., routes found through search with priority on distance, priority on ordinary roads, and priority on toll roads) is displayed on the liquid crystal display  15 . Out of the routes for which guidance is displayed, the user selects a planned traveling route (guidance route) of the vehicle. Subsequently, the navigation device  1  provides guidance for traveling on the basis of the planned traveling route thus selected. 
     At S 3 , the CPU  41  acquires the departure point and the destination. The departure point may be the current position of the vehicle, or may be any location (e.g., home) designated by the user. The destination is acquired based on operation (e.g., operation of searching for or selecting a facility) of the user that the operating unit  14  receives. 
     Next, at S 4 , the CPU  41  prepares candidate routes that are candidates for the recommended route. The preparation of the candidate routes is performed by using a known Dijkstra&#39;s algorithm. Specifically, the route search is performed from the departure point side and also from the destination side. In the overlapping area between the search from the departure point side and the search from the destination side, a cost added value is calculated that is a value obtained by adding up the search cost (the node cost and the link cost) accumulated from the departure point side, the search cost accumulated from the destination side, and the toll cost based on tolls required for the travel. The CPU  41  specifies a certain number of (e.g., a maximum of five) routes as the candidate routes in ascending order of the cost added value thus calculated. 
     The processing of the following S 5  to S 11  is performed for each candidate route prepared at S 4  described above. After the processing of S 5  to S 11  is performed for all of the prepared candidate routes, the process proceeds to S 12 . 
     At S 5 , the CPU  41  determines whether an automated driving section is included in each candidate route to be processed. This automated driving section is a section where the automated driving control is basically performed when the vehicle travels in this section as described above and, for example, an expressway falls thereunder. 
     If it is determined that an automated driving section is included in the candidate route to be processed (YES at S 5 ), the process proceeds to S 6 . If it is determined that no automated driving section is included in the candidate route to be processed (NO at S 5 ), the process proceeds to S 11 . 
     At S 6 , the CPU  41  determines whether, about the automated driving section included in the candidate route to be processed, there is an interruption record of the automated driving control recorded when the vehicle traveled in this section in the past. The interruption record of the automated driving control includes information specifying the location (the start position and the end position of the interruption), the time, and the distance of the interruption of the automated driving control and the reasons for the interruption. The interruption record of the automated driving control may be stored in the data recording unit  12 , or may be stored in an external server. Furthermore, if the interruption record is stored in the external server, in addition to the interruption record of the vehicle, interruption records of other vehicles may be also stored therein. 
     If it is determined that, about the automated driving section included in the candidate route to be processed, there is an interruption record of the automated driving control recorded when the vehicle traveled in this section in the past (YES at S 6 ), the process proceeds to S 7 . If it is determined that, about the automated driving section included in the candidate route to be processed, there is no interruption record of the automated driving control recorded when the vehicle traveled in this section in the past (NO at S 6 ), the process proceeds to S 8 . 
     At S 7 , about the automated driving section included in the candidate route to be processed, the CPU  41  acquires the interruption record of the automated driving control recorded when the vehicle traveled in this section in the past. Specifically, when the interruption record of the automated driving control is stored in the data recording unit  12 , the interruption record is read out from the data recording unit  12 . If the interruption record of the automated driving control is alternatively stored in the external server, the interruption record is acquired by communicating with the external server. 
     Subsequently, at S 8 , the CPU  41  specifies a section (hereinafter, called “interruption section”) where the automated driving control is interrupted in the automated driving section included in the candidate route. As the interruption section, a section where a situation occurs in which it is difficult for the vehicle to perform the automated driving control is specified base on road shapes, lane markings, traffic information, weather information, and interruption records of the automated driving control in the past, for example. In the interruption section, the automated driving control of the vehicle is interrupted, and traveling by the manual driving is performed. For example, a section that falls under any of the conditions (1) to (5) below is specified as an interruption section. 
     (1) a section where merging or lane change is necessary in a short distance (e.g., 500 meters or shorter). 
     (2) a section where lane markings (e.g., a roadway centerline, a lane boundary, a roadway outside line) disappear or fade to the extent that the lane markings cannot be recognized by a camera. 
     (3) a section where lanes are restricted due to an accident, construction, or a fallen object, for example, and which lane is restricted cannot be identified. 
     (4) a section where the weather is so bad (e.g., heavy rain, dense fog, snow cover, icy road) that it is difficult to perform detection with a camera and sensors or it is difficult to perform vehicle control when the vehicle travels. 
     (5) a section where the automated driving control was interrupted in the past other than the sections that fall under the conditions of (1) to (4). 
     Whether a section falls under the conditions (1) to (4) is determined based on, for example, map information, VICS information, probe information, vehicle-to-vehicle communication, and road-to-vehicle communication. Whether a section falls under the condition (5) is determined based on the interruption record acquired at S 7  described above. Note that the interruption section specified at S 8  described above is a temporarily specified one, and is subjected to coupling of interruption sections at S 9  described later to be finally determined and set as an interruption section. Furthermore, the setting of the interruption section is basically performed during route search (S 8 , S 9 ), and is also performed when the vehicle is traveling after the route search as described later (S 47  in  FIG. 10 ). 
     Next, at S 9 , the CPU  41  performs interruption-section coupling processing ( FIG. 7 ) described later. The interruption-section coupling processing is processing for connecting interruption sections that satisfy a certain condition and are adjacently arranged along a candidate route as described later to set one continuous interruption section. 
     Subsequently, at S 10 , based on the interruption section set at S 8  and S 9  described above, the CPU  41  acquires interruption information indicating that the automated driving control is interrupted in the candidate route to be processed. The interruption information contains the number of times, durations, distances, and locations of the interruption of the automated driving control in the candidate route to be processed and the reasons for the interruption. Herein, the times, the distances, the locations, and the reasons are acquired for the respective interruption sections. 
     Subsequently, at S 11 , the CPU  41  calculates, for the candidate route to be processed, a decision value D that is an index for selection of a recommended route. Specifically, the decision value D is calculated by a method described below. 
     To begin with, a required time T (minute) necessary for the vehicle to travel in a candidate route is acquired. The required time T is calculated based on map information, and traffic information, for example. Next, to the required time T thus calculated, an additional value α based on the interruption information acquired at S 10  described above is added. The sum of the required time T and the additional value α is set as a decision value D. The additional value α is calculated by using at least one or more of the number of times, durations, distances, locations of the interruption of the automated driving control and the reasons for the interruption. For example, any one of or the sum of some of (A) to (C) below is set as the additional value α. (A) two minutes multiplied by the number of times that the automated driving control is interrupted on the candidate route, (B) sum (minute) of durations during which the automated driving control is interrupted on the candidate route, (C) sum (km) of distances for which the automated driving control is interrupted on the candidate route. 
     When the additional value α is calculated by using locations where the automated driving control is interrupted, calculation is made such that the additional value α is larger as a location of the interruption is closer to the destination on the candidate route. For example, the ratio of “the distance from the departure point to the interruption end point” to “the total length of the candidate route” is multiplied by “the required time×0.1”, and the product is set as the additional value α. When a plurality of interruption sections exist, the additional value α may be calculated for each of the interruption sections, and the decision value D may be calculated by using only the largest additional value α, or the decision value D may be calculated by adding all the calculated additional values α to the required time T. 
     When the additional value α is calculated by using reasons for the interruption of the automated driving control, calculation is made such that the additional value α is larger as it is more difficult for the vehicle to travel by the automated driving control. Herein,  FIG. 3  is a figure illustrating an example of correspondence between additional values α and reasons for the interruption of the automated driving control. For example, in the case where the candidate route includes a section that is set as an interruption section because merging or lane change is performed in a short section (e.g., 500 meters or shorter), particularly when the candidate route includes an interruption section where merging or lane change is performed in a distance longer than 100 meters and equal to or shorter than 500 meters, the additional value α is calculated to be “1”. When the candidate route includes an interruption section where merging or lane change is performed in a distance equal to or shorter than 100 meters, the additional value α is calculated to be “2”. When the road shape of the interruption section where merging or lane change is performed cannot be identified from map information, the additional value α is calculated to be “3”. In the case where the candidate route includes a section that is set as an interruption section because of snow cover or an icy road when the vehicle travels, particularly when the candidate route includes an interruption section for which icy road information exists in VICS information, the additional value α is calculated to be “3”. When the candidate route includes an interruption section for which VICS information does not exist but the snowfall probability is high according to the weather forecast (e.g., 80% or higher), the additional value α is calculated to be “2”. When the candidate route includes an interruption section for which VICS information does not exist and the snowfall probability is low according to the weather forecast (e.g., lower than 80%), the additional value α is calculated to be “1”. In the same manner, for other reasons, the additional values are calculated as depicted in  FIG. 3 . Herein, when there are a plurality of interruption sections, the additional value α may be calculated for each of the interruption sections, and the decision value D may be calculated by using only the largest additional value α, or the decision value D may be calculated by adding all the additional values α calculated to the required time T. 
     If no automated driving section is included in the candidate route to be processed (NO at S 5 ), the required time T (minute) necessary for the vehicle to travel on the candidate route is set to be the decision value D. After the decision values D are calculated for all of the candidate routes prepared at S 4  described above, the process proceeds to S 12 . 
     At S 12 , the CPU  41  selects a recommended route from among the candidate routes prepared at S 4  described above. Specifically, the CPU  41  compares the decision values D of the respective candidate routes and selects, from among the candidate routes, the candidate route having the smallest decision value D as the recommended route. Herein, the recommended route may be selected in plurality. Note that, at S 12 , as a recommended route, the candidate route having the smallest decision value D is selected regardless of whether an interruption section is included therein. Thus, there are occasions when a candidate route including an interruption section is selected as a recommended route, and there are occasions when a candidate route including no interruption section is selected as a recommended route. 
     Next, at S 13 , the CPU  41  provides guidance about the respective pieces of information on the recommended route selected at S 12  described above and the other candidate routes other than the recommended route. Herein, guidance only about the information on the recommended route may be provided. Alternatively, among the candidate routes other than the recommended route, not all of these routes but only a certain number of (e.g., two in the ascending order of the decision value D) routes may be picked up as routes the guidance for which is provided. In particular, when an automated driving section is included in the recommended route or in the other candidate routes, guidance is provided in a manner distinguishing a section that corresponds to an interruption section from a section that does not correspond thereto. In other words, guidance about the section that corresponds to an interruption section and guidance about the section that does not correspond thereto are provided in different guidance manners. Furthermore, when guidance for the recommended route and the other candidate routes is provided, guidance about the interruption information acquired at S 10  described above is provided together. 
       FIG. 4  and  FIG. 5  are diagrams illustrating a route guidance screen  51  that provides guidance for a recommended route and candidate routes other than the recommended route displayed on the liquid crystal display  15  at S 13  described above. As depicted in  FIG. 4  and  FIG. 5 , on the route guidance screen  51 , an information window  52  is displayed that displays information on the recommended route and other candidate routes to be guided in a list form for each route. The route that is particularly selected by a cursor  53  in the information window  52  is displayed in a manner superimposed on the map image at the left side of the screen. For example,  FIG. 4  depicts the route guidance screen  51  in which the recommended route  54  is selected, and  FIG. 5  depicts the route guidance screen  51  in which the candidate route  55  other than the recommended route is selected. In the information window  52 , information particularly containing interruption information is displayed as information on the recommended route, for example. Specifically, (a) the number of times that the automated driving control is interrupted on the route, (b) the total distance for which the automated driving control is interrupted on the route, and (c) the required time are displayed for each route. Herein, the total duration during which the automated driving control is interrupted on the route may be displayed. The information window  52  is displayed in a sorted manner, which specifically provides guidance for a route with a higher priority in a prioritized manner among the candidate routes. The priorities are basically set to be higher for a smaller decision value D, but may be set based on the number of times, durations, distances, and locations of the interruption of the automated driving control and the reasons for the interruption. When the recommended route  54  or the candidate route  55  displayed in a manner superimposed on the map image at the left side of the screen includes an automated driving section, the displaying is performed such that a section that corresponds to the automated driving section is distinguished from a section that does not correspond thereto. For example, in the examples depicted in  FIG. 4  and  FIG. 5 , the automated driving sections are indicated by solid lines, and sections other than the automated driving sections are indicated by dashed lines. In particular, for each section corresponding to an interruption section in the automated driving section, a section-specifying line segment  56  connecting between the start point and the end point of the interruption section is displayed so as to distinguish the section from the other sections. Furthermore, near each section-specifying line segment  56 , the reason for the interruption of the automated driving control is displayed with an interruption icon  57 . For example, in the route guidance screen  51  depicted in  FIG. 5 , interruption sections exist at two locations on the candidate route  55 , and it is indicated that the interruption section on the departure point side is set as an interruption section because of being a section where merging needs to be performed in a short section. It is also indicated that the interruption section on the destination side is set as an interruption section because of being a section where lanes are restricted due to an accident, construction, or a fallen object, for example, and which lane is restricted cannot be identified. 
     By watching the route guidance screen  51  displayed on the liquid crystal display  15 , the user can understand the recommended route and the candidate routes other than the recommended route from the departure point to the destination and where and how the automated driving control is interrupted when traveling on the respective routes (e.g., the numbers of times, durations, distances, and locations of the interruption of the automated driving control and the reasons for the interruption). 
     Next, at S 14 , the CPU  41  determines a planned traveling route (guidance route) of the vehicle on the basis of operation of the user from among the recommended route and the candidate routes other than the recommended route for which guidance is provided at S 13  described above. Herein, the CPU  41  may be configured to determine the recommended route as the planned traveling route without having the user make a selection. Subsequently, for sections in the automated driving section included in the planned traveling route from which interruption sections are excluded, the CPU  41  sets control contents (e.g., going straight, changing lanes to the right, merging) of the automated driving control performed on the vehicle. 
     For example, the example depicted in  FIG. 6  is an example of the control contents of the automated driving control that is set when sections a to f constitute an automated driving section in the planned traveling route of the vehicle. In the example depicted in  FIG. 6 , for the sections a to d, and f obtained by excluding the section e from the sections a to f because the section e is an interruption section, the control contents of the automated driving control are set. The control contents of the automated driving control are basically determined based on the planned traveling route and map information and, for example, for a section where merging into a main lane in an IC, for example, is necessary, “merging” is set as a control content of the automated driving control. For a section where lane change is necessary to move into another expressway at a JCT, for example, “changing lanes to the right (left)” is set. The information specifying the planned traveling route and the control contents thus set are transmitted to the vehicle control ECU  20  through the CAN. Consequently, when the vehicle starts traveling, the vehicle control ECU  20  performs automated driving control after the start of traveling on the basis of the information received from the navigation device  1 . 
     The following describes sub-processing of interruption-section coupling processing performed at S 9  described above with reference to  FIG. 7 .  FIG. 7  is a flowchart of a sub-processing program of the interruption-section coupling processing. 
     To begin with, at S 21 , the CPU  41  determines, for each candidate route to be processed, whether the number of interruption sections specified at S 8  described above is more than one. 
     If it is determined that, for the candidate route to be processed, the number of interruption sections specified at S 8  described above is more than one (YES at S 21 ), the process proceeds to S 22 . If it is determined that the number of interruption sections is only one or no interruption section is included (NO at S 21 ), the process proceeds to S 10  without performing coupling on interruption sections. 
     The processing from the following S 22  to S 28  is performed on each interruption section included in the candidate route to be processed. To begin with, the processing is performed on the interruption section closest to the departure point, and then the processing is performed in order from the interruption section closer to the departure point. The processing from S 22  to S 28  is performed on up to the interruption section second closest to the destination, and then the process proceeds to S 10 . 
     At S 22 , the CPU  41  acquires each of a start point X 1 , an end point X 2 , and a distance L 1  (=|X 2 −X 1 |) of an interruption section to be processed. 
     Next, at S 23 , the CPU  41  acquires each of a start point Y 1 , an end point Y 2 , and a distance L 2  (=|Y 2 −Y 1 |) of an interruption section to be subsequently processed (i.e., an interruption section that is set adjacently to the interruption section to be processed on the destination side). 
     Subsequently, at S 24 , the CPU  41  calculates a distance L 3  (=|X 2 −Y 1 |) between the interruption section to be processed (hereinafter, called “first interruption section”) and the interruption section to be subsequently processed (hereinafter, called “second interruption section”). 
     Subsequently, at S 25 , the CPU  41  predicts a vehicle speed V of the vehicle traveling between the first interruption section and the second interruption section. The vehicle speed V may be a speed limit (e.g., 80 km/h) of a road specified based on map information, or may be an average vehicle speed in the corresponding section acquired from VICS information or probe information. The vehicle speed V is preferably predicted in consideration of traffic information such as congestion information. 
     Subsequently, at S 26 , based on the distance L 3  calculated at S 24  described above and the vehicle speed V predicted at S 25  described above, the CPU  41  calculates a required time Z (=L 3 /V) that is necessary for the vehicle to travel from the end point of the first interruption section to the start point of the second interruption section. 
     Next, at S 27 , the CPU  41  determines whether the required time Z calculated at S 26  described above is equal to or shorter than a predetermined threshold. The threshold that is a criterion for determination at S 27  described above is set based on road types and road shapes, for example, which is a period of time considered to be the upper limit for the interval of switching between the automated driving control and the manual driving to make the user feel troublesome, and is set to be one minute, for example. Herein, the user may set the value of the threshold. Alternatively, at S 27  described above, instead of whether the required time Z is equal to or shorter than the threshold, the CPU  41  may be configured to determine whether the distance L 3  between the first interruption section and the second interruption section is equal to or shorter than a threshold (e.g., one kilometer). 
     If it is determined that the required time Z calculated at S 26  described above is equal to or shorter than the predetermined threshold (YES at S 27 ), the process proceeds to S 28 . If it is determined that the required time Z calculated at S 26  described above is longer than the predetermined threshold (NO at S 27 ), the process returns to S 22 , and after changing the interruption section to be processed, the processing at and after S 22  is performed again. 
     At S 28 , the CPU  41  connects the first interruption section and the second interruption section, thereby setting these interruption sections as one continuous interruption section. For example, a case will be described in which two interruption sections of the interruption section A and the interruption section B are set adjacently along the candidate route as depicted in  FIG. 8 . In this case, if the interruption sections are not coupled together at S 28  described above, the automated driving control is performed up to the point X 1 , the manual driving is performed from the point X 1  to the point X 2 , the automated driving control is performed from the point X 2  to the point Y 1 , the manual driving is performed from the point Y 1  to the point Y 2 , and the automated driving control is performed from the point Y 2 . Thus, switching between the automated driving control and the manual driving is performed frequently. In contrast, if the interruption section A and the interruption section B are connected and one new interruption section C starting at X 1  and ending at Y 2  is set at S 28  described above, the manual driving is continuously performed from the point X 1  to the point Y 2 , so that the switching between the automated driving control and the manual driving can be prevented from being performed frequently. 
     Subsequently, the process returns to S 22 , and after changing the interruption section to be processed, the processing at and after S 22  is performed again. The processing from S 22  to S 28  is performed on up to the interruption section second closest to the destination, and then the process proceeds to S 10 . 
     The following describes the automated-driving-control processing program that the CPU  41  executes in the navigation device  1  according to the first embodiment with reference to  FIG. 9 .  FIG. 9  is a flowchart of the automated-driving-control processing program according to the first embodiment. This automated-driving-control processing program, which is executed at predetermined intervals (e.g., intervals of 100 milliseconds) after the planned traveling route (guidance route) of the vehicle has been determined at S 14  described above, is a program for determining continuation of the automated driving control and newly setting an interruption section. 
     To begin with, in the automated-driving-control processing program, at S 31 , the CPU  41  determines whether the automated driving start button is ON. This automated driving start button is disposed on the instrument panel, for example, and switches between ON and OFF every time the user depresses the button. When the automated driving start button is turned ON while the vehicle is traveling in the automated driving section (from which sections specified as interruption sections are excluded), the automated driving control is started. When the automated driving start button is turned OFF while the automated driving control is being performed, the automated driving control is ended and switched into the manual driving even if the vehicle is traveling in the automated driving section. 
     If it is determined that the automated driving start button is ON (YES at S 31 ), the process proceeds to S 34 . If it is determined that the automated driving start button is not ON (NO at S 31 ), the process proceeds to S 32 . 
     At S 32 , the CPU  41  determines whether the automated driving control of the vehicle is being performed. 
     If it is determined that the automated driving control of the vehicle is being performed (YES at S 32 ), the process proceeds to S 33 . If it is determined that the automated driving control of the vehicle is not being performed (NO at S 32 ), the automated-driving-control processing program is ended. 
     At S 33 , the CPU  41  performs end processing of the automated driving control. Specifically, the CPU  41  transmits an instruction signal for instructing the vehicle control ECU  20  to end the automated driving control through the CAN. Consequently, the vehicle ends the automated driving control and shifts to the manual driving. 
     At S 34 , the CPU  41  determines whether the vehicle is located in the automated driving section on the basis of the current position of the vehicle detected by the current-position detecting unit  11  and map information. The current position of the vehicle is preferred to be precisely identified by using a high-accuracy location technology. Such a high-accuracy location technology makes it possible to detect traveling lanes and the accurate position of the vehicle by detecting, through image recognition, white lines and road marking information captured by a camera mounted on the rear of the vehicle, and further by comparing the white lines and the road marking information with the map information DB stored in advance. Details of the high-accuracy location technology are already publicly known, and thus description thereof is omitted. 
     If it is determined that the vehicle is located in the automated driving section (YES at S 34 ), the process proceeds to S 35 . If it is determined that the vehicle is not located in the automated driving section (NO at S 34 ), the process proceeds to S 32 . 
     At S 35 , the CPU  41  performs interruption-section detection processing ( FIG. 10 ) described later. This interruption-section detection processing is processing for detecting, other than a section already set as an interruption section, a section where a situation occurs in which it is difficult for the vehicle to travel by the automated driving control to newly set this section as an interruption section, as described later using the vehicle exterior camera  19  and sensors, for example, while the vehicle is traveling. 
     Next, at S 36 , the CPU  41  determines whether the automated driving control is being interrupted. As described above, even while the vehicle is traveling in an automated driving section, when the vehicle is located in a set interruption section, the automated driving control of the vehicle is interrupted and the vehicle travels by the manual driving. 
     If it is determined that the automated driving control is being interrupted (YES at S 36 ), the process proceeds to S 39 . If it is determined that the automated driving control is not being interrupted (NO at S 36 ), the process proceeds to S 37 . 
     At S 37 , the CPU  41  determines whether the vehicle has entered an interruption section. Such interruption sections are preset for a planned traveling route on which the vehicle travels in the route-search processing program ( FIG. 2 ,  FIG. 7 ) described above. The interruption sections are set also in the interruption-section detection processing ( FIG. 10 ) described later. 
     If it is determined that the vehicle has entered an interruption section (YES at S 37 ), the process proceeds to S 38 . At S 38 , the CPU  41  performs interruption processing of the automated driving control. Specifically, the CPU  41  transmits an instruction signal for instructing the vehicle control ECU  20  to temporarily interrupt the automated driving control through the CAN. Consequently, the vehicle temporarily interrupts the automated driving control and shifts to the manual driving. If it is determined that the vehicle has not entered an interruption section (NO at S 37 ), the automated driving control is continuously performed. 
     At S 39 , the CPU  41  determines whether the vehicle has exited an interruption section. 
     If it is determined that the vehicle has exited an interruption section (YES at S 39 ), the process proceeds to S 40 . At S 40 , the CPU  41  performs resuming processing of the automated driving control. Specifically, the CPU  41  transmits through the CAN an instruction signal for instructing the vehicle control ECU  20  to resume the automated driving control that has been interrupted. Consequently, the vehicle resumes the automated driving control that has been interrupted and shifts to the automated driving control from the manual driving. If it is determined that the vehicle has not exited an interruption section (NO at S 39 ), the interruption of the automated driving control is continued. 
     The following describes sub-processing of the interruption-section detection processing performed at S 35  described above with reference to  FIG. 10 .  FIG. 10  is a flowchart of a sub-processing program of the interruption-section detection processing. 
     To begin with, at S 41 , the CPU  41  acquires the current position of the vehicle on the basis of the detection result of the current-position detecting unit  11 . The current position of the vehicle is preferably identified by using the high-accuracy location technology. 
     Next, at S 42 , the CPU  41  acquires route information ahead of the vehicle in the traveling direction. For example, the CPU  41  acquires route information within one kilometer from the current position of the vehicle along the planned traveling route. 
     Subsequently, at S 43 , the CPU  41  determines whether connection is established with an external server storing interruption records of the automated driving control of other vehicles and/or a traffic information server such as a VICS center. 
     If it is determined that connection is established with an external server storing interruption records of the automated driving control of other vehicles and/or a traffic information server such as a VICS center (YES at S 43 ), the CPU  41  acquires (at S 44 ) the latest interruption records of the automated driving control and/or the latest traffic information for sections (hereinafter, called “detection target sections”) ahead of the vehicle in the traveling direction for which the route information is acquired from the server at S 42  described above. If it is determined that connection is not established with an external server storing interruption records of the automated driving control of other vehicles or a traffic information server such as a VICS center (NO at S 43 ), the process proceeds to S 45 . 
     At S 45 , the CPU  41  determines whether connection is established with a camera and/or sensors, for example, for detecting external environment of the vehicle. Examples of the sensors include a millimeter wave radar for detecting an obstacle, a rain sensor for detecting rainfall and snow cover, and an illuminance sensor. 
     If it is determined that connection is established with a camera and/or sensors for detecting external environment of the vehicle (YES at S 45 ), external environment around the vehicle is detected by the camera and/or the sensors connected (S 46 ). If it is determined that connection is not established with a camera or sensors for detecting external environment of the vehicle (NO at S 45 ), the process proceeds to S 47 . 
     Subsequently, at S 47 , based on the interruption records and/or the traffic information acquired at S 44  described above and the external environment detected at S 46  described above, the CPU  41  determines whether a section where a situation in which it is difficult for the vehicle to travel by the automated driving control occurs exists among the sections, except a section already set as an interruption section, ahead of the vehicle in the traveling direction for which the route information is acquired at S 42  described above. If it is determined that a section where a situation in which it is difficult for the vehicle to travel by the automated driving control occurs exists, this section is newly specified as an interruption section. The interruption section specified at S 47  described above is an interruption section that could not specified during route search but can be specified first when the vehicle reaches an actual place. For example, a section that falls under any of the conditions (6) to (9) below is specified as an interruption section. 
     (6) a section for which an interruption record did not exist during the route search but, during a period until the vehicle reaches the actual place, an interruption record is newly generated when another vehicle interrupts the automated driving control. 
     (7) a section where lanes are newly restricted due to an accident, construction, or a fallen object, for example, after the route search, and which lane is restricted cannot be identified. 
     (8) a section where the fact that lane markings (e.g., a roadway centerline, a lane boundary, a roadway outside line) disappear or fade to the extent that the lane markings cannot be recognized with a camera is newly detected by capturing images of the road surface with the camera.
 
(9) a section for which the weather becomes so bad (e.g., heavy rain, dense fog, snow cover, icy road) that it is difficult to perform detection with a camera and sensors or it is difficult to perform vehicle control, which could not be predicted during the route search.
 
     Next, at S 48 , the CPU  41  determines whether an interruption section has been newly specified at S 47  described above. 
     If it is determined that an interruption section has been newly specified (YES at S 48 ), the process proceeds to S 49 . If it is determined that no interruption section has been newly specified (NO at S 48 ), the process proceeds to S 36  without newly setting an interruption section in particular. 
     At S 49 , the CPU  41  performs the interruption-section coupling processing ( FIG. 7 ) described above. The interruption-section coupling processing is processing for connecting interruption sections that satisfy a certain condition and are adjacently arranged along a candidate route as described above to set one continuous interruption section. Thus, because an interruption section is newly specified at S 47  described above, decision about coupling of interruption sections is made for this new interruption section, and if necessary, the coupling of interruption sections is performed. Note that when the vehicle speed V of the vehicle traveling between the first interruption section and the second interruption section is predicted at S 25 , the current vehicle speed of the vehicle (at the time when the new interruption section is specified) is preferably acquired with the vehicle speed sensor  23 , and the vehicle speed V of the vehicle traveling between the first interruption section and the second interruption section is preferably predicted to be this acquired vehicle speed. 
     Next, at S 50 , the CPU  41  changes the control contents of the automated driving control set at S 14  described above on the basis of the newly specified and coupled interruption section. Specifically, for a section that is newly set as an interruption section, the CPU  41  changes the control contents such that the automated driving control is not performed. Accordingly, the control contents of the automated driving control for other sections are changed if necessary. The control contents thus changed are transmitted to the vehicle control ECU  20  through the CAN. Consequently, it is possible to perform the automated driving control into which the newly specified and coupled interruption section is reflected. 
     As described above in detail, with the navigation device  1 , the route searching method with the navigation device  1 , and the computer program executed in the navigation device  1  according to the first embodiment, when a recommended route from a departure point to a destination including an automated driving section where automated driving control of the vehicle is performed is searched for, a plurality of candidate routes that are candidates for the recommended route are acquired (S 4 ); for each of the candidate routes acquired, an interruption section where the automated driving control is interrupted in the automated driving section included in the candidate route is specified (S 8 , S 9 ); based on the interruption section specified, for each of the candidate routes, interruption information indicating that the automated driving control is interrupted in the automated driving section included in the candidate route is acquired (S 10 ); and, based on the interruption information acquired, the recommended route is selected from among the candidate routes (S 12 ). Thus, when a route to a destination is searched for, a recommended route can be selected in consideration of an interruption section where automated driving control is interrupted. By using interruption information on interruption of the automated driving control, while preventing the occurrence of a situation in which an excessively long roundabout route is searched for or route search fails, it is possible to select a more appropriate recommended route for the user. 
     Second Embodiment 
     The following describes a navigation device according to a second embodiment with reference to  FIG. 11 . In the following description, reference numerals that are the same as those in the structure of the navigation device  1  according to the first embodiment depicted in  FIG. 1  to  FIG. 10  described above indicate components that are the same or equivalent as those in the navigation device  1  according to the first embodiment, for example. 
     The schematic structure of the navigation device according to the second embodiment is substantially the same as the structure of the navigation device  1  according to the first embodiment. The various types of control processing thereof are substantially the same as the control processing of the navigation device  1  according to the first embodiment. However, these are different in the following point. In the navigation device  1  according to the first embodiment, the navigation device  1  determines, during route search, an interruption section where the automated driving control is interrupted, and the vehicle control ECU  20  controls the vehicle in accordance with the interruption section determined by the navigation device  1  during the route search. By contrast, in the navigation device according to the second embodiment, the navigation device  1  only specifies, during route search, a section (hereinafter, called “interruption-predicted section”) where there is a possibility that the automated driving control will be interrupted, and the interruption-predicted section thus specified does not affect whether the automated driving is actually interrupted (i.e., determination of whether the automated driving control is interrupted is determined by the navigation device and the vehicle control ECU  20  while the vehicle is traveling in the automated driving section). 
     The route-search processing program executed by the CPU  41  in the navigation device according to the second embodiment is basically the same in processing as the route-search processing program ( FIG. 2 ) according to the first embodiment except that interruption sections are replaced with interruption-predicted sections. The automated-driving-control processing program is also basically the same in processing as the automated-driving-control processing program ( FIG. 9 ) according to the first embodiment. However, in the route-search processing program according to the second embodiment, a section where there is a possibility that the automated driving control will be interrupted is only predicted, so that interruption-predicted sections specified at S 8  and S 9  described above may be different from sections where the automated driving control is actually interrupted. Thus, the control contents (see  FIG. 6 ) of the automated driving control determined at S 14  are changed as needed while the vehicle is traveling. 
     The interruption-section coupling processing at S 9  is also performed on the interruption-predicted sections. Consequently, when interruption-predicted sections where there is a possibility that the automated driving control will be interrupted are included in a recommended route or other candidate routes, interruption-predicted sections that are adjacently arranged can be connected to set one continuous interruption-predicted section. Thus, it is possible to accurately match the interruption-predicted sections to the sections where the automated driving control is actually interrupted. It is also possible to modify the shapes of the interruption-predicted sections into shapes that the user can easily understand, without making the shapes complicated. 
     In the navigation device according to the second embodiment, at S 10  described above, based on interruption-predicted sections set at S 8  and S 9  described above, the CPU  41  acquires interruption-predicting information indicating that the automated driving control is predicted to be interrupted for each candidate route to be processed. The interruption-predicting information contains probabilities that the automated driving control will be actually interrupted in the interruption-predicted sections, in addition to the number of times, durations, distances, and locations of the predicted interruption of the automated driving control in the candidate route to be processed and the reasons for the interruption. 
     At S 11 , when calculating the decision value D for the candidate route, the CPU  41  may use the probabilities that the automated driving control will be interrupted to calculate the additional value α, in addition to the number of times, the durations, the distances, the locations of the predicted interruption of the automated driving control and the reasons for the interruption. 
     For example, when the probabilities that the automated driving control will be interrupted are used to calculate the additional value α, this calculation is performed such that a higher probability of interruption produces a larger additional value α.  FIG. 11  is a figure illustrating an example of correspondence between additional values α and probabilities that automated driving control will be interrupted. For example, in the case where the candidate route includes a section that is set as an interruption-predicted section because merging or lane change is performed in a short section (e.g., 500 meters or shorter), particularly when the candidate route includes an interruption-predicted section where merging or lane change is performed in a distance longer than 100 meters and equal to or shorter than 500 meters, because merging or lane change can be performed in a relatively easy manner even by the automated driving control, the probability that the automated driving control will be interrupted is low, and the additional value α is calculated to be “1”. When the candidate route includes an interruption-predicted section where merging or lane change is performed in a distance equal to or shorter than 100 meters, because it is difficult to perform merging or lane change by the automated driving control, the probability that the automated driving control will be interrupted is high, and the additional value α is calculated to be “2”. When the road shape of the interruption-predicted section where merging or lane change is performed cannot be identified from map information, because the automated driving control cannot be basically performed, the additional value α is calculated to be “3”. In the case where the candidate route includes a section that is set as an interruption-predicted section because of snow cover or an icy road when the vehicle travels, particularly when the candidate route includes an interruption-predicted section for which icy road information exists in VICS information, the probability that the weather will become so bad that it is difficult to perform detection with a camera and sensors or it is difficult to perform vehicle control and accordingly the automated driving control will be interrupted when the vehicle travels in this section is determined to be remarkably high, and the additional value α is calculated to be “3”. In the case where the candidate route includes an interruption-predicted section for which VICS information does not exist but the snowfall probability is high according to the weather forecast (e.g., 80% or higher), the probability that the weather will become so bad that it is difficult to perform detection with a camera and sensors or it is difficult to perform vehicle control and accordingly the automated driving control will be interrupted when the vehicle travels in this section is determined to be high, and the additional value α is calculated to be “2”. In the case where the candidate route includes an interruption-predicted section for which VICS information does not exist and the snowfall probability is low (e.g., lower than 80%) according to the weather forecast, the probability that the weather will become so bad that it is difficult to perform detection with a camera and sensors or it is difficult to perform vehicle control and accordingly the automated driving control will be interrupted when the vehicle travels in this section is determined to be low, and the additional value α is calculated to be “1”. In the same manner, for other reasons, the additional values are calculated based on the probabilities that the automated driving control will be interrupted as depicted in  FIG. 11 . Herein, when there are a plurality of interruption-predicted sections, the additional value α may be calculated for each of the interruption-predicted sections, and the decision value D may be calculated by using only the largest additional value α, or the decision value D may be calculated by adding all the additional values α calculated to the required time T. Consequently, the decision value D of a candidate route including an interruption-predicted section where the automated driving control is interrupted with a higher probability can be calculated to be larger (which makes it difficult for this route to be selected as a recommended route), and thus a more appropriate recommended route can be selected. 
     Herein, the structure for calculating the decision values D of the candidate routes on the basis of the numbers of times, durations, distances, and locations of the predicted interruption of the automated driving control and the reasons for the interruption is the same as that in the first embodiment, and thus description thereof is omitted. 
     In the navigation device according to the second embodiment, when guidance about information on a recommended route and other candidate routes other than the recommended route is provided at S 13 , the guidance may be provided in a manner depending on the probabilities that the automated driving control will be interrupted. Specifically, display colors or display patterns of interruption-predicted sections included in a recommended route, for example, are changed in accordance with the interruption probabilities. For example, in the route guidance screen  51  depicted in  FIG. 5 , an interruption-predicted section where the interruption probability is predicted to be high (80% or higher) can be displayed in red, an interruption-predicted section where the interruption probability is predicted to be medium (lower than 80% and equal to or higher than 50%) can be displayed in green, and an interruption-predicted section where the interruption probability is predicted to be low (lower than 50%) can be displayed in blue. Consequently, by watching the route guidance screen  51 , the user can easily understand in which section and at what probability the automated driving control will be interrupted. 
     As described above in detail, with the navigation device, the route searching method with the navigation device, and the computer program executed in the navigation device according to the second embodiment, when a recommended route from a departure point to a destination including an automated driving section where automated driving control of the vehicle is performed is searched for, a plurality of candidate routes that are candidates for the recommended route are acquired; for each of the candidate routes acquired, an interruption-predicted section where there is a possibility that the automated driving control will be interrupted in the automated driving section included in the candidate route is specified; based on the interruption-predicted section specified, for each of the candidate routes, interruption-predicting information indicating that the automated driving control is predicted to be interrupted in the automated driving section included in the candidate route is acquired; and, based on the interruption-predicting information acquired, the recommended route is selected from among the candidate routes. Thus, when a route to a destination is searched for, a recommended route can be selected in consideration of an interruption-predicted section where there is a possibility that automated driving control will be interrupted. By using interruption-predicting information on interruption prediction of the automated driving control, while preventing the occurrence of a situation in which an excessively long roundabout route is searched for or route search fails, it is possible to select a more appropriate recommended route for the user. 
     It should be noted that the present disclosure is not limited to the embodiments described above, and as a matter of course, various improvements and modifications can be made within a scope not departing from the gist of the present disclosure. 
     For example, in the first embodiment and the second embodiment, sections where the automated driving control is interrupted or may be interrupted in an automated driving section are specified (S 8 , S 47 ). However, sections where the manual driving is interrupted to perform the automated driving control or sections where there is a possibility that the manual driving will be interrupted to perform the automated driving control may be specified. In this case, sections that do not fall under any of the conditions (1) to (5) above are sections where the manual driving is interrupted to perform the automated driving control or sections where there is a possibility that the manual driving will be interrupted to perform the automated driving control. For the sections thus specified, the interruption-section coupling processing depicted in  FIG. 7  can be performed in the same manner. Furthermore, each decision values D is calculated based on information indicating that the manual driving is interrupted or is predicted to be interrupted, whereby a recommended route is selected. In the calculation of the decision value D at S 11 , in contrast to the first embodiment and the second embodiment, the additional value α is set to be a smaller value as the number of times, durations, or distances of the interruption of the manual driving or predicted to be interrupted increase. The additional value α is set to be a smaller value when the location where the manual driving is interrupted or is predicted to be interrupted is located closer to the destination on the candidate route. 
     In the first embodiment and the second embodiment, the navigation device  1  is configured to set control contents (e.g., going straight, changing lanes to the right, merging) of the automated driving control that is performed on the vehicle. Alternatively, the vehicle control ECU  20  may be configured to set the control contents of automated driving. The control contents of the automated driving control do not necessarily have to be set during route search, and may be set by the time the vehicle reaches the automated driving section. 
     In the first embodiment and the second embodiment, the interruption-section detection processing ( FIG. 10 ) described above is performed when the vehicle is traveling in an automated driving section, but may be performed only when the vehicle is traveling in an interruption section in particular. In this case, when an interruption section is newly specified at S 47 , an interruption section where the vehicle is currently located and the interruption section newly specified are coupled together at S 49 . Furthermore, when the interruption-section detection processing ( FIG. 10 ) is performed only when the vehicle is traveling in the interruption section, a detection range (i.e., a range within which route information is acquired at S 42 , a range within which interruption information and traffic information are acquired at S 44 , and a detection range of a camera and sensors at S 46 ) within which a section where the automated driving control needs to be interrupted is newly detected may be set ahead of the vehicle in the traveling direction in accordance with the vehicle speed of the vehicle. For example, as the vehicle speed of the vehicle increases, the detection range is set wider. Consequently, the required time Z from the end point of the interruption section where the vehicle is currently located to the start point of the interruption section newly specified is inevitably equal to or shorter than the threshold, which enables the processing at S 22  to S 27  to be omitted. 
     In the first embodiment and the second embodiment, description has been made assuming that the automated driving control for traveling in an automated way without driving operation of the user means that, out of operations of the vehicle, all of accelerator operation, brake operation, and steering operation that are operations related to vehicle behavior are controlled by the vehicle control ECU  20 . However, as the automated driving control, the vehicle control ECU  20  may be configured to control, out of operations of the vehicle, at least one of accelerator operation, brake operation, and steering operation that are operations related to vehicle behavior. By contrast, description is made assuming that the manual driving by driving operation of the user means that, out of operations of the vehicle, all of accelerator operation, brake operation, and steering operation that are operations related to vehicle behavior are performed by the user. 
     In the first embodiment and the second embodiment, the navigation device  1  is configured to perform the route change processing program ( FIG. 2 ) and the automated driving control program ( FIG. 9 ). Alternatively, the vehicle control ECU  20  may be configured to perform these programs. In this case, the vehicle control ECU  20  is configured to acquire the current position of the vehicle, map information, and traffic information, for example, from the navigation device  1 . 
     The present disclosure can be also applied to devices having a route search function in addition to navigation devices. For example, the present disclosure can be applied to mobile phones, smart phones, tablet terminals, personal computers, for example (hereinafter, called “mobile terminals, etc.”). The present disclosure can be also applied to a system including a server and mobile terminals, etc. In this case, any of the server and the mobile terminals, etc. may be configured to perform the respective steps of the route change processing program ( FIG. 2 ) and the automated driving control program ( FIG. 9 ) described above. Note that when the present disclosure is applied to the mobile terminals, etc., connection needs to be established such that the mobile terminals, etc. can communicate with vehicles that can perform automated driving control (regardless of whether the connection is wired or wireless). 
     Examples in which the route searching system according to the present disclosure is embodied have been described in the foregoing, but the route searching system may have structures described below. In this case, effects described below are obtained. 
     For example, the first structure is as follows. 
     The route searching system includes interruption information that contains any of number of times, a duration, a distance, and a location of the interruption of the automated driving control and a reason for the interruption. 
     With the route searching system having this structure, the recommended route can be selected in consideration of how the automated driving control is interrupted in detail. Thus, it is possible to select a more appropriate recommended route for the user. 
     The second structure is as follows. 
     The route searching system includes interruption-predicting information that contains any of the number of times, a duration, a distance, and a location of the predicted interruption of the automated driving control and a reason for the interruption. 
     With the route searching system having this structure, the recommended route can be selected in consideration of how the automated driving control may be interrupted in detail. Thus, it is possible to select a more appropriate recommended route for the user. 
     The third structure is as follows. 
     The route searching system includes recommended-route selecting code that acquires, for each of the candidate routes, a required time necessary for the vehicle to travel on the candidate route, calculates a decision value obtained by adding an additional value based on the interruption information or the interruption-predicting information to the required time for each of the candidate routes, and compares the decision values of the respective candidate routes to select the recommended route. 
     With the route searching system having this structure, by using such a decision value calculated from specific values as an index for selecting a recommended route, a recommended route suitable for the user can be easily selected even if there are many candidate routes. Because the evaluation index is converted into a numerical form, it is possible to simplify the processing for selecting a recommended route thereby reducing the processing load. 
     The fourth structure is as follows. 
     The route searching system includes recommended-route selecting code that selects, from among the candidate routes, a candidate route having the decision value that is smallest as the recommended route. 
     With the route searching system having this structure, the decision values of the respective candidate routes are compared to select a candidate route having the smallest decision value as a recommended route, thus a recommended route suitable for the user can be accurately and quickly selected even if there are many candidate routes. 
     The fifth structure is as follows. 
     The route searching system includes an additional value that is set to be a larger value as the number of times, the duration, or the distance of the interruption or the predicted interruption of the automated driving control increases. 
     With the route searching system having this structure, a candidate route on which the automated driving control is less frequently interrupted can be selected with a higher priority as a recommended route. Thus, a more appropriate recommended route can be selected for a user who wants to travel by the automated driving control. 
     The sixth structure is as follows. 
     The route searching system includes an additional value that is set to be a larger value at a location, where the automated driving control is interrupted or predicted to be interrupted, that is closer to the destination on each of the candidate routes. 
     With the route searching system having this structure, a candidate route on which the automated driving control is less frequently interrupted in the latter half of the route where the user feels more fatigue due to driving can be selected with a higher priority as a recommended route. Thus, a more appropriate recommended route can be selected for a user who wants to travel by the automated driving control. 
     The seventh structure is as follows. 
     In the route searching system the interruption-predicting information contains a probability that the automated driving control will be interrupted in the interruption-predicted section, and the recommended-route selecting code acquires, for each of the candidate routes, a required time necessary for the vehicle to travel on the candidate route, calculates a decision value obtained by adding an additional value based on the probability to the required time for each of the candidate routes, and compares the decision values of the respective candidate routes to select the recommended route. 
     With the route searching system having this structure, by using such a decision value calculated based on the probability that the automated driving control will be interrupted as an index for selecting a recommended route, a recommended route suitable for the user can be easily selected even if there are many candidate routes. Because the evaluation index is converted into a numerical form, it is possible to simplify the processing for selecting a recommended route thereby reducing the processing load. 
     The eighth structure is as follows. 
     In the route searching system the additional value is set to be a larger value as the probability that the automated driving control will be interrupted increases. 
     With the route searching system having this structure, a candidate route on which the probability that the automated driving control will be interrupted is lower can be selected with a higher priority as a recommended route. Thus, a more appropriate recommended route can be selected for a user who wants to travel by the automated driving control. 
     The ninth structure is as follows. 
     In the route searching system the interruption section specifying code or the interruption-predicted section specifying code uses any of a road shape, a lane marking, traffic information, weather information, and a past interruption record of the automated driving control to specify the interruption section or the interruption-predicted section. 
     With the route searching system having this structure, a section where a situation occurs in which it is difficult for the vehicle to travel by the automated driving control can be appropriately specified as an interruption section or an interruption-predicted section. 
     The tenth structure is as follows. 
     The route searching system further include recommended route guidance code for providing guidance for the recommended route selected by the recommended-route selecting code in a manner distinguishing the interruption section or the interruption-predicted section. 
     With the route searching system having this structure, the user can easily understand where the automated driving control is interrupted when traveling on the recommended route. 
     The eleventh structure is as follows. 
     The route searching system further includes control content setting code for, for a section in the automated driving section included in the recommended route selected by the recommended-route selecting code from which the interruption section or the interruption-predicted section is excluded, setting control contents of the automated driving control that is performed on the vehicle. 
     With the route searching system having this structure, considering in advance a section where the automated driving control is interrupted, it is possible to set the control contents of the automated driving control that is performed on the vehicle traveling on a recommended route. This eliminates the need of setting the control contents of the automated driving control while traveling, and also eliminates the need to modify the set control contents every time the automated driving control is interrupted, thereby making it possible to reduce the processing load related to the automated driving control. 
     The twelfth structure is as follows. 
     The route searching system includes route candidate acquisition code that acquires as the candidate routes, out of routes from the departure point to the destination, a certain number of routes that are specified in ascending order of cost added value that is an accumulated value of a search cost. 
     With the route searching system having this structure, the number of candidate routes that are candidates for a recommended route can be narrowed down to the certain number in advance based on the cost added value. 
     The thirteenth structure is as follows. 
     The route searching system further includes driving intention acquisition code for acquiring whether a user wants to travel by the automated driving control in the automated driving section, and when the user wants to travel by the automated driving control in the automated driving section, the route searching system determines that the vehicle travels by the automated driving control in an automated driving section included in the candidate routes to search for the recommended route, and when the user does not want to travel by the automated driving control in the automated driving section, the route searching system determines that the vehicle travels by manual driving in an automated driving section included in the candidate routes to search for the recommended route. 
     With the route searching system having this structure, also considering the user&#39;s intention on whether to travel by the automated driving control, it is possible to search for an appropriate recommended route. 
     The fourteenth structure is as follows. 
     A route searching system that searches for a recommended route from a departure point to a destination including an automated driving section where a vehicle is allowed to perform automated driving control in addition to manual driving includes: route candidate acquisition codes for acquiring a plurality of candidate routes that are candidates for the recommended route; manual interruption section specifying code for, for each of the candidate routes acquired by the route candidate acquisition code, specifying a manual-driving interruption section where the manual driving is interrupted and the automated driving control is performed in the automated driving section included in the candidate route; manual interruption information acquisition code for, based on the manual-driving interruption section specified by the manual interruption section specifying code, for each of the candidate routes, acquiring interruption information indicating that the manual driving is interrupted in the automated driving section included in the candidate route; and recommended-route selecting code for selecting the recommended route including the manual-driving interruption section from among the candidate routes, based on the interruption information acquired by the manual interruption information acquisition code. 
     With the route searching system having this structure, when searching for a route to a destination, it is possible to select a recommended route considering an interruption section where the manual driving is interrupted (i.e., a section where the automated driving control is performed). By using interruption information on interruption of the manual driving, while preventing the occurrence of a situation in which an excessively long roundabout route is searched for or route search fails, it is possible to select a more appropriate recommended route for the user. 
     The fifteenth structure is as follows. 
     A route searching system that searches for a recommended route from a departure point to a destination including an automated driving section where a vehicle is allowed to perform automated driving control in addition to manual driving includes: route candidate acquisition code for acquiring a plurality of candidate routes that are candidates for the recommended route; manual-interruption-predicted section specifying code for, for each of the candidate routes acquired by the route candidate acquisition code, specifying a manual-driving-interruption-predicted section where there is a possibility that the manual driving will be interrupted and the automated driving control will be performed in the automated driving section included in the candidate route; manual-interruption-predicting information acquisition code for, based on the manual-driving-interruption-predicted section specified by the manual-interruption-predicted section specifying code, for each of the candidate routes, acquiring interruption-predicting information indicating that the manual driving is predicted to be interrupted in the automated driving section included in the candidate route; and recommended-route selecting code for selecting the recommended route including the manual-driving-interruption-predicted section from among the candidate routes, based on the interruption-predicting information acquired by the manual-interruption-predicting information acquisition code. 
     With the route searching system having this structure, when searching for a route to a destination, it is possible to select a recommended route considering an interruption-predicted section where there is a possibility that the manual driving will be interrupted (i.e., a section where the automated driving control is predicted to be performed). By using interruption-predicting information on interruption prediction of the manual driving, while preventing the occurrence of a situation in which an excessively long roundabout route is searched for or route search fails, it is possible to select a more appropriate recommended route for the user. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
     
         
         
           
               1  navigation device 
               13  navigation ECU 
               14 . operating unit 
               15  liquid crystal display 
               41  CPU 
               42  RAM 
               43  ROM 
               51  route guidance screen 
               52  information window 
               54  recommended route 
               55  candidate route 
               56  section-specifying line segment 
               57  interruption icon