JP2001059736A - Route guiding device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a route guiding device for a vehicle for properly obtaining an optimal route even when a vehicle reaches a place which is congested with traffic at the time of re-calculating an optimal route for preventing any place which is congested with traffic from the present position of the vehicle to the destination. SOLUTION: This route guiding device for a vehicle is provided with an azimuth sensor 1, a speed sensor 2, a map storage memory 3, a CPU 4, an ROM 5, an RAM 6, a V-RAM 7, a display 8, an operation board 9, and a receiving device 10. When congestion information is received by the receiving device 10, a CPU 4 judges whether or not the congestion information is related with the optimal route. When the congestion information is related with the optimal route, the CPU 4 weights the data of the map storage memory 3 by the congestion information. Then, the CPU 4 sets a spot on the optimal route which is the closest to the present position as the start point of calculation, and operates route retrieval from the spot to the destination. When the vehicle reaches a place which is congested with traffic in the middle, a route for preventing the congested place where the vehicle reaches is displayed as long as an arithmetic operation of preventing the congested place is ended. Then, the new start point of calculation is set, and route retrieval for preventing the other places which are congested with traffic ahead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle route guidance apparatus for searching for a route from a current position to a destination, finding an optimum route, and guiding a vehicle to a destination according to the optimum route.

[0002]

2. Description of the Related Art A route guidance device for a vehicle for searching for a route from a current position of a vehicle to a destination to obtain an optimum route, displaying the optimum route and the current position of the vehicle on a road map, and guiding an occupant to the destination. It has been known. Also, JP-A-2-129800
In this publication, a traffic information is received by a receiver provided in a vehicle, and a calculation reference point (hereinafter, referred to as a node) on a map is weighted based on congestion information in the received traffic information to search for a route. Is disclosed.

[0003]

However, the apparatus described in the above publication performs a route search after weighting all nodes on the map, so that it takes a lot of time until an optimum route is determined. In addition, it is often the case that a vehicle receives traffic information while the vehicle is traveling, and if the above-described calculation with traffic congestion information added from the point at which the traffic information is received to the destination is performed, the calculation is completed before the calculation is completed. The vehicle reaches a traffic jam,
Eventually, the vehicle may be caught in traffic.

[0004] It is an object of the present invention to calculate an optimum route for avoiding a location that hinders traffic from the current position of the vehicle to the destination, even if the vehicle arrives at a location that hinders traffic. It is an object of the present invention to provide a vehicular route guidance device for obtaining an optimum route.

[0005]

The present invention will be described with reference to FIG. 1 showing an embodiment. To achieve the above objectives,
The invention according to claim 1 includes a road map storage unit 3 for storing road map data, vehicle position detection units 1 and 2 for detecting a current position of a vehicle, a destination setting unit 9 for setting a destination, and road map data. The present invention is applied to a vehicle route guidance device including first calculation means 4 for performing a route search from the current position to a destination based on the first route to calculate an optimum route, and display means 8 for displaying the calculated optimum route. A traffic information receiving means 10 for receiving traffic information including information, a judging means 4 for judging whether or not the traffic information is related to the optimum route, and a traffic when the judging means 4 judges that the traffic information is related. A traffic information storage unit 4 for storing information, a location specifying unit 4 for specifying all specific locations that hinder traffic on the optimal route based on the traffic information stored in the traffic information storage unit 4;
Based on the traffic information stored in the traffic information storage means 4,
A second calculating means for recalculating an optimum route for avoiding a specific point from the current position of the vehicle to the destination; and a display means for displaying the optimum route calculated by the second calculating means. When the vehicle arrives at any one of the specific places, only when the second calculation means 4 has completed the calculation of the optimal route for avoiding the specific place at which the vehicle has arrived,
An optimal route for avoiding the reached specific location is displayed. The invention of claim 2 includes a road map storage means 3 for storing road map data, vehicle position detection means 1 and 2 for detecting the current position of the vehicle, a destination setting means 9 for setting a destination, and a road map data. The present invention is applied to a vehicle route guidance device including first calculation means 4 for performing a route search from the current position to a destination based on the first route to calculate an optimum route, and display means 8 for displaying the calculated optimum route. Traffic information receiving means 10 for receiving traffic information including information
Determining means 4 for determining whether or not the traffic information is related to the optimum route; and traffic information storing means 4 for storing the traffic information when the determining means 4 determines that there is a relation.
Based on the traffic information stored in the traffic information storage means 4, a location specifying means 4 for specifying all the specific points which hinder traffic on the optimal route; and a traffic information stored in the traffic information storage means 4. And a second calculating means 4 for recalculating an optimal route for avoiding a specific point from the current position of the vehicle to the destination based on the second calculating means, and the display means 8 is calculated by the second calculating means. The second calculating means displays the optimum route for avoiding a specific location between the current position of the vehicle and the destination, and then selects the specific location where the vehicle is specified before the calculation of the optimum route is completed. When the vehicle arrives, an optimum route for avoiding a specific location for which a specific location closer to the destination than the reached specific location has not yet been calculated is calculated. The invention according to claim 3 is a road map storage means 3 for storing road map data, vehicle position detecting means 1 and 2 for detecting the current position of a vehicle, and a destination setting means 9 for setting a destination.
First calculating means 4 for performing a route search from the current position to the destination based on the road map data to calculate an optimal route
And a traffic information receiving means 10 for receiving traffic information including traffic congestion information, which is applied to a vehicle route guidance device having display means 8 for displaying the calculated optimal route, and traffic information related to the optimal route. Determination means 4 for determining whether or not the traffic information is stored, when the determination means 4 determines that there is a relationship, a traffic information storage means 4 for storing traffic information; Based on the traffic information stored in the traffic information storage means 4, based on the traffic information stored in the traffic information storage means 4. And a second calculating means 4 for recalculating an optimum route for avoiding the problem, wherein the display means 8 displays the optimum route calculated by the second calculating means, and displays the vehicle at any one of the specific locations. When it reaches Only when the second calculating means 4 has completed the calculation of the optimal route for avoiding the arriving specific location, the optimal route for avoiding the arriving specific location is displayed. If the vehicle reaches one of the specified locations before the calculation of the optimal route to avoid the specific location between the vehicle's current location and the destination is completed, the vehicle is located closer to the destination than the specified location. For a location, an optimal route for avoiding a specific location for which an optimal route for avoiding the specific location has not yet been computed is computed.

[0006]

According to the first aspect of the present invention, the determining means determines whether or not the traffic information received by the traffic information receiving means is related to the optimum route calculated by the first calculating means. Is done. The traffic information determined to be relevant by the determination means 4 is stored by the traffic information storage means 4, and based on the stored traffic information, all of the specific locations which interfere with traffic on the optimal route are specified by the specifying means 4. Specified. To avoid this specific location, a new optimal route is calculated by the second calculating means 4. When the vehicle arrives at any of the specific locations, the optimal route for avoiding the specific location is calculated. Only when is completed, the display unit 8 displays the optimum route for avoiding the specific location. Thus, it is possible to avoid a situation in which the guidance route is not displayed on the display unit because the optimum route is being calculated. According to the second aspect of the present invention, if the vehicle reaches any one of the specific locations before the calculation of the optimal route for avoiding the specific location from the current position of the vehicle to the destination, the vehicle moves from the specific location to the target location. For a specific location close to the ground, an optimal route for a specific location for which an optimal route for avoiding the specific location has not yet been calculated is calculated by the second calculating means 4. As a result, the optimum route for avoiding the specific location is calculated individually. According to the third aspect of the present invention, only when the calculation of the optimal route for avoiding the specific location has been completed, the optimal route for avoiding the specific location is displayed by the display means 8. If the vehicle arrives at any one of the specific locations before the calculation of the optimal route to avoid the specific location from the current location to the destination is completed, the specific location closer to the destination than the specific location is still at the specific location Is calculated by the second calculating means 4 for a specific portion for which the optimum route for avoiding the above is not calculated. Thus, it is possible to avoid a situation in which the guidance route is not displayed on the display unit because the optimum route is being calculated, and to individually calculate the optimum route for avoiding the specific location.

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0008]

FIG. 1 is a block diagram of a vehicle route guidance apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an azimuth sensor, which detects a traveling azimuth of a vehicle by detecting, for example, geomagnetism at a position where the vehicle exists. Reference numeral 2 denotes a vehicle speed sensor which is attached to, for example, a transmission of the vehicle and outputs a predetermined number of pulse signals according to the vehicle speed. Three
Is a map storage memory for storing road map data including intersection network data, and 4 is a CPU for performing a route search in accordance with the processing of FIGS. Reference numeral 5 denotes a ROM for storing a control program of the CPU 4 and the like, and reference numeral 6 denotes a RAM for storing a route search result calculated by the CPU 4.
Reference numeral 7 denotes a V-RAM for storing image data generated by the CPU 4, and the data stored in the V-RAM 7 is displayed on a display 8. Reference numeral 9 denotes an operation board for selecting a map to be displayed on the display 8, selecting a scale of the map, instructing to start a route search, correcting a current position display position, inputting a destination, and the like. A receiving device 10 receives traffic information transmitted by a beacon transmitter, FM multiplex broadcasting, or the like. Direction sensor 1, vehicle speed sensor 2, map storage memory 3, CPU 4, ROM 5, RAM 6, V-RAM
7, display 8, operation board 9, and receiving device 10
Are connected to each other via an interface circuit 11.

In the vehicle route guidance apparatus configured as shown in FIG. 1, the CPU 4 measures the number of pulses or pulse period per unit time output from the vehicle speed sensor 2 during traveling of the vehicle, thereby determining the traveling speed of the vehicle. , And the running distance of the vehicle is detected by measuring the number of pulses. Next, the CPU 4 calculates the traveling locus of the vehicle based on the detected traveling distance of the vehicle and the traveling direction of the vehicle detected by the direction sensor, and performs map matching with the road map data stored in the map storage memory 3. To determine the current location of the vehicle.

When the destination of the vehicle is input from the operation board 9, the CPU 4 executes a known Dijkstra method (Japanese Patent Laid-Open No. 62-8 / 1987).
For example, a route search is performed from the current position to the destination to obtain an optimum route. The cost of each node (the path length from the departure point to each node) obtained by this route search is stored in the RAM 6. In addition, RAM6
Is the node immediately before each node and has the shortest route from the departure point (hereinafter, referred to as the immediately preceding node)
Is stored for each node. By tracing the immediately preceding node stored in the RAM 6 in order from the destination, an optimal route from the destination to the departure point is obtained. The optimum route obtained in this way is displayed on the display 8.

FIGS. 2 and 3 are diagrams showing an example of a route search result by the CPU 4, wherein the optimum route from the departure point A to the destination I of the vehicle is indicated by a bold line, and the other routes are indicated by a thin line. The points marked with a circle in FIGS. 2 and 3 represent nodes,
The number displayed on the route between the nodes (hereinafter, referred to as a link) indicates the distance of each link. The numerical value in parentheses below each node indicates the cost of each node, and this cost indicates the shortest distance from the departure point. 2 and 3, the current location of the vehicle is indicated by an arrow. When the vehicle starts running, the receiving device 10 continuously receives radio waves transmitted from a beacon transmitter, FM multiplex broadcasting, or the like. The received information is sent to the CPU 4, and the CPU 4 extracts the congestion information from the traffic information based on the reception code. When the traffic congestion information is extracted, the CPU 4 starts the avoidance route calculation processing shown in the flowchart of FIG.

Hereinafter, the avoidance route calculation processing by the CPU 4 will be described with reference to FIG. In step S1, it is determined whether or not the traffic jam information received by the receiving device 10 is related to the optimal route. This determination is made by comparing a digital code included in the transmitted radio wave for identifying a congested point with a code stored in the map storage memory 3. If the determination is negative, the process returns. If the determination is positive, step S is executed.
Move to 2. FIG. 2B shows an example in which traffic congestion information between nodes D and E and between nodes F and H is received while the vehicle is traveling between nodes B and C (broken line portion in the figure). Since this traffic congestion information relates to a node on the optimal route, step S1 in FIG. 4 is affirmed and the process proceeds to step S2. Step S
In the second section, the optimal route data from the current location to the destination is stored in RA
Save to M6. That is, the optimum route data before receiving the traffic jam information is saved in the RAM 6 before the route search is performed again with the traffic jam information added.

In step S3, each link in the road map data is weighted by a coefficient corresponding to the degree of congestion based on the received congestion information. For example, in FIG. 2B, the congestion coefficient between the nodes D and E is 3, the congestion coefficient between the nodes F and G is 2.5, and the congestion coefficient between the nodes G and H is 4 based on the received congestion information. If something is detected,
By the weighting process in step S3, the link between the nodes D and E changes from 2 to 6, the link between the nodes F and G changes from 2 to 5,
The link between nodes G and H changes from 1 to 4. In step S4, a point where the avoidance route calculation is started is set. Specifically, a congestion point on the optimal route closest to the current position in the vehicle traveling direction is detected, and this point is set as a calculation start point. In the example of FIG. 2B, the node D is set as the calculation start point (the “☆” point in FIG. 2B).

In step S5, the destination I input by the operation board 9 is set as a calculation end point (FIG. 2).
(“★” point in (b)). In step S6, avoidance route candidate points are set. Here, each node on the optimal route before the reception of the traffic jam information is set as an avoidance route candidate point. FIG.
In the example of (b), the nodes E, F, G, and H are set as avoidance route candidate points (points indicated by “●”). In this case,
The other nodes on the optimum route are not directly related to the avoidance route, and are not set as the avoidance route candidate points. In step S7, the cost of each node in the avoidance route candidate points is changed to a value weighted by the traffic congestion information. For example, FIG.
Cost of node E of 4 + 2 + 3 + 6 = 15, node F
Is 15 + 3 = 18, and the cost of node G is 18+
5 = 23, the cost of the node H is 23 + 4 = 27, and the cost of the destination I is 27 + 1 = 28.

Next, in step S8, a route search is performed again by the Dijkstra method from the calculation start point to the destination according to the flowchart of FIG. 5 described later, and the cost of each node and the immediately preceding intersection are updated. In step S9,
It is determined whether a route search has been performed to the destination. As will be described later, the vehicle may reach the congestion start point during the processing in FIG. 5. In such a case, the vehicle is guided to the point where the optimum route is determined for the time being, and the calculation start point is set again. To search for a route to the destination. Therefore, if the determination in step S9 is negative, the process proceeds to step S4, while if the determination in step S9 is positive, the process returns.

FIG. 5 is a flowchart for explaining the details of the processing in step S8 in FIG. In step S21,
Set the calculation start point to the central node. In the example of FIG. 2B, first, the node D is set as the central node. In step S22, it is determined whether or not the center node is the destination. If the determination is negative, the process shifts to step S23 to determine whether or not the center node is an avoidance route candidate point. If the determination is affirmative, the process moves to step S24, the central node is set as an end candidate point, and the process moves to step S25.

If the determination is negative in step S23, the process also proceeds to step S25, and the cost update processing is performed for all nodes adjacent to the central node. In this cost update process, the cost of each node before receiving the congestion information and the cost of each node after adding the congestion information are compared. If the latter has a smaller cost value, the cost of that node is Value, and if the former is smaller, do not change the cost value.

For example, in the example of FIG. 2B, the cost of the node E before receiving the congestion information is 4 + 2 + 3 + 2 = 11, but when the cost is calculated on the same route (D → E) after the reception of the congestion information. , "15". On the other hand, when going from the departure point to the node E, the cost when passing through the route of D → J → K → E is 4 + 2 + 3 + 2 + 2 + 1 = 14,
The cost is smaller than the case of passing through the route from D to E. Therefore, in this step S25, “14” is set as the cost of the node E, and the node K is set as the node immediately before the node E.

In step S26, the node whose cost has been updated in the cost update process in step S25 is added to the central node candidate list. That is, in the above case, the node E
Is registered in the central node candidate list. Step S27
Then, among the group of nodes existing in the central node candidate list, the node with the lowest cost is set as the central node. In step S28, it is determined whether the vehicle has reached the calculation start point. If the determination is negative, the process returns to step S22.

Thereafter, by repeating the processing of steps S22 to S28, the central node gradually approaches the destination, and when the avoidance route is finally calculated to the destination, the determination in step S22 is affirmed and the process proceeds to step S29. I do. In step S29, the destination which is the central node is set as an end candidate point, and the routine goes to step S30. In step S30, the optimum route is obtained by sequentially following the immediately preceding node from the destination, the result is stored in the RAM 6, and the process ends. For example, in the example of FIG.
The route indicated by the thick line in (c) is set as the optimal route.

On the other hand, if it is determined in step S28 that the vehicle has approached the calculation start point, the flow shifts to step S31 to determine whether or not there is a candidate end point. A node that can be an end candidate point is a node on the optimal route before receiving the traffic jam information, and an optimal route from this end candidate point to the destination has already been obtained before the traffic jam information is received. That is, if the avoidance route calculation is performed from the calculation start point to the end candidate point, the vehicle can be guided to the destination by the optimal route before the traffic jam information is received. Is determined.

If the determination in step S31 is affirmative, the process proceeds to step S30 to detect an optimal route. For example, in FIG. 2B, when the vehicle approaches the calculation start point when the avoidance route calculation is performed to the central node E, the node E
Is an end candidate point, the optimal route detected in step S30 is the thick-line route in FIG. That is,
From node D to node E, the avoidance route calculated in the processing of FIG. 5 is selected, and after node E, the optimal route before receiving the traffic jam information is selected.

On the other hand, if a negative determination is made in step S31, the processing in FIG. 5 ends. That is, when there is no end candidate point, the vehicle is guided on the optimum route before receiving the traffic jam information without using the result of the processing in FIG.

When the vehicle reaches the calculation start point during the processing of FIG. 5 and, for example, the thick line route in FIG. 3A is selected,
Step S9 in FIG. 4 is denied and the process returns to step S4.
As a result, as shown in FIG.
Is set as the calculation start point. Then, the cost of each node and the immediately preceding node are changed again, and as a result, FIG.
Is set as a route indicated by a bold line.

As described above, in the above-described embodiment, after the optimum route is obtained without adding the traffic jam information, the congestion point on the optimum route closest to the current position of the vehicle is set as the calculation start point, and the target Since the route search is performed after adding the traffic congestion information toward the ground, an optimum route that takes the traffic congestion information into consideration can be obtained in a relatively short time. If the vehicle arrives at a traffic jam before the route search to the destination is completed, the vehicle is determined based on the avoidance route calculation result up to that point and the route search result performed before receiving the traffic information. Since the vehicle is guided, even when there is not enough time to complete the avoidance route calculation process, for example, even when the vehicle receives traffic information near a traffic congestion point, the vehicle can be guided to a route that avoids traffic congestion. Furthermore, when the vehicle reaches a congested point during the avoidance route calculation process, the vehicle is once guided to the avoidance route, and the calculation start point is set again to perform the avoidance route calculation process. It is possible to cope with a case where there are many places or a place where traffic congestion frequently changes.

In the above embodiment, the route that requires the shortest time to reach the destination is selected as the optimal route.
A route with the shortest distance to reach the destination may be selected. When displaying the optimal route obtained by the processing of FIG. 5 on the display 8, the optimal route may be displayed in a color different from that of the optimal route before the traffic jam information is received, to alert the driver.

In the embodiment constructed as described above, the map storage memory 3 is used as road map storage means, the direction sensor 1 and the vehicle speed sensor 2 are used as vehicle position detection means, and the operation board 9 is used.
Is the destination setting means, the CPU 4 is the first calculating means, the display 8 is the display means, the receiving device 10 is the traffic information receiving means, step S1 in FIG. 4 is the determining means, and steps S3 and S7 in FIG. Corresponds to the traffic information storage means, step S4 in FIG. 4 corresponds to the specifying means, and FIG. 5 corresponds to the second calculation means.

[0028]

Since the present invention is configured as described above, it has the following effects. According to the first aspect of the present invention, when the vehicle reaches a specific location before the calculation of the optimal route for avoiding all the specific locations related to the optimal route, the specific location is avoided. Only when the calculation of the optimal route has been completed, the optimal route is displayed. Therefore, when the vehicle reaches a specific location, only the optimal route for avoiding the specific location is displayed first. be able to. This prevents the driver from being confused by displaying a route on which the optimal route is not determined. According to the second aspect of the present invention, if the vehicle arrives at any one of the specific locations during the calculation of the optimal route for avoiding the specific location, the optimal route for avoiding the specific location has not yet been calculated. Since the optimum route for the specific portion is calculated, the optimum route for avoiding the specific portion can be calculated individually. Accordingly, it is possible to cope with a case where the number of specific portions is too large to perform the calculation or a case where the specific portions frequently change. According to the invention set forth in claim 3, it is possible to simultaneously achieve the effect described in claim 1 and the effect described in claim 2.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a vehicle route guidance device according to the present invention.

FIG. 2 is a diagram illustrating an example of a route search result.

FIG. 3 is a diagram illustrating an example of a route search result.

FIG. 4 is a flowchart illustrating an avoidance route calculation process performed by a CPU.

FIG. 5 is a flowchart showing details of step S8 in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Direction sensor 2 Vehicle speed sensor 3 Map storage memory 4 CPU 5 ROM 6 RAM 7 V-RAM 8 Display 9 Operation board 10 Receiving device 11 Interface device

Claims (3)

[Claims] 1. Road map storage means for storing road map data; vehicle position detection means for detecting a current position of a vehicle; destination setting means for setting a destination; and a destination from a current position based on the road map data. A vehicle route guidance apparatus comprising: first calculation means for performing a route search to the ground to calculate an optimum route; and display means for displaying the calculated optimum route. A traffic for receiving traffic information including congestion information. Information receiving means; determining means for determining whether or not the traffic information is related to the optimal route; and traffic information storing means for storing the traffic information when the determining means determines that the traffic information is related. An identification unit that identifies all specific locations that hinder traffic on the optimal route based on the traffic information stored in the traffic information storage unit; A second calculating unit that recalculates an optimal route for avoiding the specific location from the current position of the vehicle to the destination based on the traffic information stored in the display unit; The optimum route calculated by the second calculating means is displayed, and when the vehicle reaches any of the specific places, the second calculating means calculates the optimum route for avoiding the arriving specific place. A route guidance device for a vehicle, wherein an optimal route for avoiding the reached specific location is displayed only when it has been completed. 2. Road map storage means for storing road map data; vehicle position detection means for detecting a current location of a vehicle; destination setting means for setting a destination; and a destination from a current location based on the road map data. A vehicle route guidance apparatus comprising: first calculation means for performing a route search to the ground to calculate an optimum route; and display means for displaying the calculated optimum route. A traffic for receiving traffic information including congestion information. Information receiving means; determining means for determining whether or not the traffic information is related to the optimal route; and traffic information storing means for storing the traffic information when the determining means determines that the traffic information is related. An identification unit that identifies all specific locations that hinder traffic on the optimal route based on the traffic information stored in the traffic information storage unit; A second calculating unit that recalculates an optimal route for avoiding the specific location from the current position of the vehicle to the destination based on the traffic information stored in the display unit; Displaying the optimum route calculated by the second calculation means, wherein the second calculation means determines whether the vehicle is to be driven before the calculation of the optimum route for avoiding the specific location from the current position of the vehicle to the destination is completed. Reaches any of the specific locations,
For a specific location closer to the destination than the reached specific location, an optimal route for avoiding a specific location for which an optimal route for avoiding the specific location has not yet been calculated is calculated. apparatus. 3. Road map storage means for storing road map data; vehicle position detection means for detecting a current position of a vehicle; destination setting means for setting a destination; and a destination from a current position based on the road map data. A vehicle route guidance apparatus comprising: first calculation means for performing a route search to the ground to calculate an optimum route; and display means for displaying the calculated optimum route. A traffic for receiving traffic information including congestion information. Information receiving means; determining means for determining whether or not the traffic information is related to the optimal route; and traffic information storing means for storing the traffic information when the determining means determines that the traffic information is related. An identification unit that identifies all specific locations that hinder traffic on the optimal route based on the traffic information stored in the traffic information storage unit; A second calculating unit that recalculates an optimal route for avoiding the specific location from the current position of the vehicle to the destination based on the traffic information stored in the display unit; The optimum route calculated by the second calculating means is displayed, and when the vehicle reaches any of the specific places, the second calculating means calculates the optimum route for avoiding the arriving specific place. Only when it has been completed, the optimum route for avoiding the reached specific location is displayed, and the second calculating means calculates an optimal route for avoiding the specific location from the current position of the vehicle to the destination. If the vehicle reaches any of the specific locations before the calculation is completed,
For a specific location closer to the destination than the reached specific location, an optimal route for avoiding a specific location for which an optimal route for avoiding the specific location has not yet been calculated is calculated. apparatus.