JP7722157B2 - Driving assistance method and driving assistance device - Google Patents

Description

The present invention relates to a driving assistance method and a driving assistance device.

Patent Document 1 describes a driving assistance system that determines intersections that place the least burden on the driver as safe intersections based on road traffic conditions and intersection signal aspects, and searches for and presents to the driver a route that passes through the safe intersection.

JP 2016-99758 A

However, there are individual differences in the driving ability of drivers at night, and therefore even if a route passes through a safe intersection, it is not necessarily possible for the driver to drive the vehicle within the range of their driving ability at night.
The present invention aims to assist a driver in driving at night so that the driver can drive the vehicle at night within the range of the driver's driving ability.

In one aspect of the driving assistance method of the present invention, a controller executes the following processes: acquiring driving ability information, which is information about the driver's driving ability at night; reading illuminance information related to the nighttime illumination of roads from map information by referencing the map information based on the current position of the vehicle; and assisting the driver in driving based on a comparison between the acquired driving ability information and the read illuminance information.

This invention can assist drivers in driving at night, allowing them to drive their vehicle within the limits of their driving ability.

1 is a schematic diagram illustrating an example of a schematic configuration of a driving assistance device according to an embodiment. FIG. 2 is a block diagram illustrating an example of a functional configuration of a controller. FIG. 10 is an explanatory diagram of a first example of a restriction on a nighttime assistance route according to driving ability at night. FIG. 10 is an explanatory diagram of a second example of a restriction on a nighttime assistance route according to driving ability at night. FIG. 10 is an explanatory diagram of a third example of a restriction on a nighttime assistance route according to driving ability at night. 1 is a flowchart illustrating an example of a driving assistance method according to an embodiment.

Embodiments of the present invention will be described below with reference to the drawings. Note that the drawings are schematic and may differ from the actual product. Furthermore, the embodiments of the present invention shown below are examples of devices and methods that embody the technical concept of the present invention, and the technical concept of the present invention does not limit the structure, arrangement, etc. of component parts to those described below. The technical concept of the present invention may be modified in various ways within the technical scope defined by the claims.

(composition)
1 is a schematic diagram illustrating an example of a configuration of a driving assistance device according to an embodiment. A vehicle 1 includes a driving assistance device 10 that assists a driver in driving the vehicle 1.
The driving assistance control by the driving assistance device 10 of the embodiment acquires driving ability information, which is information regarding the driver's driving ability at night, and assists the driver in driving by restricting the time periods during which the driver drives the vehicle 1 and the roads on which the vehicle 1 travels, so that the driver can drive the vehicle 1 within the range of the driver's driving ability at night.
In this specification, "nighttime" refers to a brightness that the driver perceives as dark or difficult to see, and is not limited to the time period from sunset to sunrise, but may also include, for example, twilight. Furthermore, "nighttime driving ability" refers to the ability required for a driver to drive a vehicle properly and safely at night, and may include, for example, eyesight and nighttime driving experience.

The driving assistance device 10 includes a sensor 11, a positioning device 12, a map database 13, a communication device 14, a human-machine interface 15, a nighttime assistance switch 16, an external display 17, a braking/driving force generator 18, a steering force generator 19, and a controller 20. In the drawings, the database is represented as "DB," the switch as "SW," and the human-machine interface as "HMI."
The sensor 11 may include a camera that generates a surrounding image by capturing an image of the surroundings of the vehicle 1. The camera outputs the generated surrounding image to the controller 20.
The sensor 11 may also include an illuminance sensor that detects the illuminance around the vehicle 1. The illuminance sensor outputs the detection result of the illuminance around the vehicle 1 to the controller 20.

The positioning device 12 measures the current position of the vehicle 1. The positioning device 12 may be equipped with, for example, a Global Navigation Satellite System (GNSS) receiver. The GNSS receiver is, for example, a Global Positioning System (GPS) receiver, and receives radio waves from multiple navigation satellites to measure the current position of the vehicle 1. The positioning device 12 may also be equipped with an inertial navigation system.

Map database 13 stores map information including road map data. The map information may be, for example, map data for a navigation system, or high-precision map data suitable for use as a map for autonomous driving. High-precision maps are map data with higher precision than map data for navigation systems, and contain more detailed lane-by-lane information than road-by-road information.

The map database 13 also stores illuminance information that indicates the illuminance of each road at night. For example, when the driving assistance device 10 drives the vehicle 1 on these roads at night, the driving assistance device 10 may detect the illuminance on the roads using an illuminance sensor included in the sensor 11 and store the detected illuminance in the map database 13. Furthermore, when the driving assistance device 10 drives the vehicle 1 on these roads at night, the driving assistance device 10 may recognize the illuminance on the roads from images captured by a camera included in the sensor 11 and store the detected illuminance in the map database 13.
The driving assistance device 10 may also receive illuminance information acquired when other vehicles are traveling at night and store the information in the map database 13. The driving assistance device 10 may also acquire illuminance information for each road at night from an external server device. In the following description, illuminance at night will be referred to as "nighttime illuminance."

Traffic volume information indicating the traffic volume for each road by time period may also be stored in the map database 13. When the vehicle 1 travels on these roads, the number of vehicles traveling on the road may be recognized from images captured by the camera provided in the sensor 11, and the time when the vehicle 1 traveled on the road and the recognized number of vehicles may be stored in the map database 13 to generate traffic volume information by time period.
The driving assistance device 10 may receive traffic volume information generated by other vehicles and store it in the map database 13. The driving assistance device 10 may also obtain traffic volume information from an external server device.
Attribute information representing the attributes of each road may also be stored in the map database 13. The attributes of a road may include information such as gradient, curvature, and road width.

The communication device 14 provides a communication function between the driving assistance device 10 and an external device. The communication method used by the communication device 14 may be, for example, wired communication or wireless communication via a public mobile communication network, satellite communication, road-to-vehicle communication, or vehicle-to-vehicle communication. The driving assistance device 10 can receive information about the driver's driving ability from an external server device or database via the communication device 14.
Furthermore, the driving assistance device 10 can communicate with an external terminal device such as a mobile information terminal used by the driver via the communication device 14 .

The human-machine interface 15 is an interface device that exchanges information between the driving assistance device 10 and the driver. The human-machine interface 15 includes a display device that can be seen by the driver (for example, a display screen of a navigation system or a display device provided near the meter in front of the driver's seat).
Furthermore, the human-machine interface 15 may include a speaker or a buzzer for outputting warning sounds, notification sounds, and audio information. The human-machine interface 15 may also include an operator that accepts an operation input by the driver to the driving assistance device 10. For example, the operator may be a button, a switch, a lever, a dial, a keyboard, a touch panel, or the like.

The nighttime assistance switch 16 is a switch that allows the user of the vehicle 1 to switch between enabling (ON) and disabling (OFF) the nighttime driving assistance function provided by the driving assistance device 10. The user of the vehicle 1 may be, for example, a relative of the driver, a person related to the driver, or the driver himself.
The driving assistance device 10 can determine the driver's nighttime driving ability by detecting whether the nighttime assistance switch 16 is on or off. That is, when the nighttime assistance switch 16 is off, the driving assistance device 10 can determine that the driver's nighttime driving ability is normal. On the other hand, when the nighttime assistance switch 16 is on, the driving assistance device 10 can determine that the driver's nighttime driving ability has deteriorated. Therefore, the driving assistance device 10 acquires the setting state of the nighttime assistance switch 16 as driving ability information that indicates information about the driver's nighttime driving ability.

Furthermore, the user of the vehicle 1 may set the strength of the nighttime driving restrictions on the driver by operating the nighttime assistance switch 16. For example, the user of the vehicle 1 may set the strength of the nighttime driving restrictions on the driver so that the strength is stronger when the driver's driving ability at night is lower.
The night support switch 16 may be provided separately from the human-machine interface 15 or may be provided integrally with the human-machine interface 15 .

The external display 17 is provided on the exterior surface of the vehicle body of the vehicle 1 (e.g., the roof, front, and/or rear) and displays visual information output by the controller 20 toward the outside of the vehicle 1. The external display 17 may be, for example, a display that displays text and image information output by the controller 20, or a lamp that indicates the state of the vehicle 1 or the state of the driver of the vehicle 1, etc.

The braking/driving force generating device 18 includes a driving source such as an engine and/or an electric motor that generates driving force for the vehicle 1, and a braking device (including a friction braking device and a regenerative braking device) that generates braking force for the vehicle 1.
Steering force generating device 19 is a device that applies a steering force to the steering system of vehicle 1. Steering force generating device 19 may be, for example, an electric power steering device that assists steering by the driver. Furthermore, for example, steering force generating device 19 may be a steering device that generates a steering force to steer steered wheels in accordance with the steering angle of the steering wheel in a steer-by-wire system in which the steering wheel and steered wheels can be physically separated.
The driving assistance device 10 can control the vehicle behavior of the host vehicle 1 by controlling the driving force and braking force generated by the braking/driving force generating device 18 and the steering force generated by the steering force generating device 19 .

The controller 20 is an electronic control unit (ECU) that performs driving assistance control of the host vehicle 1. The controller 20 includes a processor 21 and peripheral components such as a storage device 22. The processor 21 may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit).
The storage device 22 may include a semiconductor storage device, a magnetic storage device, an optical storage device, etc. The storage device 22 may include memories such as a register, a cache memory, a ROM (Read Only Memory) used as a main memory device, and a RAM (Random Access Memory).
The functions of the controller 20 described below are realized by, for example, the processor 21 executing a computer program stored in the storage device 22 .

The storage device 22 also stores driving ability information 23, which is information relating to the driver's driving ability at night.
For example, the driving ability information 23 may be information that directly represents the visual acuity that constitutes nighttime driving ability. The driving ability information 23 may include, for example, information on the results of a visual function test of the driver conducted by a public institution such as the police, as information on visual acuity. The driving ability information 23 may also include information on the driver's visual acuity treatment history.

For example, the driving assistance device 10 may detect the driving behavior of the driver when driving the vehicle 1 at night, and store the driver's past driving behavior history at night in the storage device 22 as driving ability information 23. For example, the difference in vehicle speed between night and day, the lateral position deviation of the vehicle 1 from the center of the lane when driving at night, and the history of reaction times at night may be stored in the storage device 22 as driving ability information 23.

For example, the driving ability information 23 may include driver attribute information that is an index of the driver's nighttime driving ability. For example, the driver attribute information may be information on the driver's age. The older the driver, the more likely the driver's visual function will decline, leading to poorer nighttime driving ability.
Furthermore, for example, the driver's attribute information may be information about the driver's driving experience at night. The driving assistance device 10 may detect the driving experience when the driver drives the vehicle 1 at night and store the information as the driver's attribute information in the storage device 22. As the driver's driving experience at night, the frequency with which the driver drives the vehicle 1 at night, driving routes that the driver is accustomed to driving the vehicle 1 at night (for example, driving routes that the driver often drives at night), and geographical areas where the driver has driven the vehicle 1 at night may be stored in the storage device 22.

Note that some or all of the driving ability information 23 may be stored in a database external to the vehicle 1. The driving assistance device 10 may receive some or all of the driving ability information 23 from an external database via the communication device 14. For example, information on the driver's visual function results and vision treatment history may be obtained from a database of a public institution.
Furthermore, some or all of the driving ability information 23 may be stored in a storage medium that is removable from the vehicle 1, and the driving ability information 23 may be acquired by the controller 20 from this storage medium. For example, the driving ability information 23 may be stored in an entry key or an electronic key (such as a key fob) used for driver authentication.

2 is a block diagram showing an example of the functional configuration of the controller 20. The controller 20 includes a driving ability information acquisition unit 30, a route setting unit 31, and a driving assistance unit 32.
The driving ability information acquisition unit 30 acquires driving ability information 23 relating to the driving ability of the driver.
For example, the driving ability information acquisition unit 30 may acquire the setting state of the nighttime support switch 16 as the driving ability information 23. For example, whether the nighttime support switch 16 is on or off may be acquired as the driving ability information 23. Furthermore, if the strength of nighttime driving restrictions on the driver is set by the nighttime support switch 16, the set strength of the nighttime driving restrictions may be acquired as the driving ability information 23.

For example, the driving ability information acquisition unit 30 may acquire driving ability information 23 stored in a storage medium removable from the vehicle 1, such as a storage device 22 provided in the controller 20, or an entry key or electronic key used for driver authentication.
For example, if driving ability information 23 regarding the driver's visual function test results and vision treatment history is provided from a driving ability database 2 external to the vehicle 1, the driving ability information acquisition unit 30 may receive the driving ability information 23 from the driving ability database 2 via the communication device 14.

The route setting unit 31 sets a travel route for driving the vehicle 1 from the current position of the vehicle 1 to the destination.
When setting a travel route, the route setting unit 31 acquires current position information of the vehicle 1 based on the measurement results of the positioning device 12. The route setting unit 31 also accepts a setting input of a destination of the vehicle 1 by the driver or a passenger. For example, the driver or a passenger may set the destination of the vehicle 1 by operating the human-machine interface 15.

Next, the route setting unit 31 reads road map data from the map database 13 by referring to the map database 13 based on the measurement results of the vehicle 1 by the positioning device 12. For example, the route setting unit 31 reads road map data for a predetermined area including the current position of the vehicle 1. The route setting unit 31 may set the area from which the road map data is read to include the current position of the vehicle 1 and the destination.
When the nighttime support switch 16 is set to OFF, the route setting unit 31 sets a normal driving route from the current location to the destination. That is, the route setting unit 31 may set the driving route regardless of the nighttime illumination of the driving route. For example, the route setting unit 31 may set the driving route using a normal route search algorithm. The same applies when the driver does not drive at night.

On the other hand, when the nighttime support switch 16 is not set to off (for example, when the nighttime support switch 16 is set to on or when the strength of the nighttime driving restrictions for the driver is set), and the driver is driving at night, the route setting unit 31 sets a driving route so that the vehicle 1 can be driven within the range of the driver's driving ability at night.
In the following description, a driving route that is set so that the vehicle 1 can be driven at night within the range of the driver's driving ability may be referred to as a "nighttime assistance route."
When setting a nighttime assistance route, the route setting unit 31 reads from the map database 13 illuminance information on nighttime illumination of roads in the area for which road map data has been read, traffic volume information, and attribute information.
The route setting unit 31 may acquire the nighttime illuminance, illuminance information, and traffic volume information from an external server device.

The route setting unit 31 compares the driving ability information 23 acquired by the driving ability information acquisition unit 30 with illuminance information acquired from the map database 13 or an external server device, and sets a nighttime assistance route from the current position to the destination via only roads with nighttime illuminance according to the driving ability indicated by the driving ability information 23. In other words, it sets a nighttime assistance route from the current position to the destination via only roads that satisfy the nighttime illuminance conditions set according to the driving ability indicated by the driving ability information 23.
For example, the route setting unit 31 may set a nighttime assistance route that passes through roads with higher nighttime illumination when the driving ability indicated by the driving ability information 23 is low compared to when the driving ability is high. In other words, the nighttime illumination condition may be set to be higher as the driving ability indicated by the driving ability information 23 is low.

3A to 3C are diagrams illustrating examples of restrictions on nighttime assistance routes according to nighttime driving ability.
For example, as shown in FIG. 3A, when the nighttime assistance switch 16 is off (i.e., when the driving ability at night is normal), a normal driving route may be set regardless of the nighttime illumination.
Furthermore, if the strength of the nighttime driving restrictions imposed on the driver is set to "weak" by the nighttime support switch 16 (i.e., if the driver's nighttime driving ability is somewhat low), a nighttime support route may be set that passes only on roads with a nighttime illumination of 5 lx or more. If the strength of the nighttime driving restrictions imposed on the driver is set to "strong" (i.e., if the driver's nighttime driving ability is low), a nighttime support route may be set that passes only on roads with a nighttime illumination of 10 lx or more.

3B, for example, if the driver is under 60 years old, a normal driving route may be set regardless of the nighttime illumination. If the driver is between 60 and 70 years old, a nighttime assistance route may be set that passes only on roads with a nighttime illumination of 5 lx or more. If the driver is 70 years old or older, a nighttime assistance route may be set that passes only on roads with a nighttime illumination of 10 lx or more.
3C, if the driver has normal eyesight, a normal driving route may be set regardless of the nighttime illumination. If the driver has slightly impaired eyesight, a nighttime assistance route may be set that passes only on roads with a nighttime illumination of 7 lx or more. If the driver has impaired eyesight, a nighttime assistance route may be set that passes only on roads with a nighttime illumination of 12 lx or more.

Furthermore, for example, when the driving ability indicated by the driving ability information 23 is low compared to when the driving ability is high, the route setting unit 31 may set a nighttime assistance route that passes through roads that present a lower driving load at night. In the following description, the driving load at night may be simply referred to as "driving load."
For example, the route setting unit 31 sets a nighttime assistance route from the current position to the destination via only roads with a driving load corresponding to the driving ability indicated by the driving ability information 23. In other words, the route setting unit 31 sets a nighttime assistance route from the current position to the destination via only roads that satisfy the driving load conditions set according to the driving ability indicated by the driving ability information 23.
For example, the driving load condition, that is, the nighttime illumination condition, may be set to be lower as the driving ability indicated by the driving ability information 23 becomes lower.

For example, since the driving load at night increases as the number of oncoming vehicles increases, the driving load condition may be defined according to the number of oncoming vehicles. For example, the driving load condition may be set to be lower as the driving ability indicated by the driving ability information 23 becomes lower.
Furthermore, for example, since the greater the gradient or curvature of the road, the greater the driving load at night, the driving load condition may be defined according to the gradient or curvature of the road. For example, the driving load condition may be set to be smaller as the driving ability indicated by the driving ability information 23 becomes lower.
Furthermore, since the narrower the road width, the higher the driving load at night, the driving load condition may be defined according to the road width. For example, the road width may be set to be wider as the driving ability indicated by the driving ability information 23 becomes lower.

For example, in the example of FIGS. 3A to 3C, the width, number of oncoming vehicles, and gradient of the roads included in the nighttime assistance route are restricted based on the driving ability indicated by the driving ability information 23.
For example, as shown in FIG. 3A, when the nighttime support switch 16 is off, the route setting unit 31 may set a normal driving route regardless of the speed limit, road width, or number of lanes.
Furthermore, when the strength of the nighttime driving restrictions imposed on the driver is set to "weak" using the nighttime support switch 16, a nighttime support route is set that passes only on roads that are 4 m or wider, that pass no more than 8 oncoming vehicles per minute, and that have a gradient of 10% or less.When the strength of the nighttime driving restrictions imposed on the driver is set to "strong," a nighttime support route is set that passes only on roads that are 5.5 m or wider, that pass no more than 3 oncoming vehicles per minute, and that have a gradient of 5% or less.

Also, for example, as shown in Figure 3B, if the driver is under 60 years old, a normal driving route may be set regardless of the speed limit, road width, or number of lanes. If the driver is between 60 and 70 years old, a nighttime support route is set that uses only roads that are 4 meters or wider, have no more than 8 oncoming vehicles passing per minute, and have a gradient of 10% or less. If the driver is 70 years old or older, a nighttime support route is set that uses only roads that are 5.5 meters or wider, have no more than 3 oncoming vehicles passing per minute, and have a gradient of 5% or less.

Also, for example, as shown in Figure 3C, if the driver's eyesight is normal, a normal driving route may be set regardless of the speed limit, road width, or number of lanes. If the driver's eyesight is slightly impaired, a nighttime support route is set that passes only on roads that are 4m or wider, have no more than five oncoming vehicles passing per minute, and have a gradient of 10% or less. If the driver's eyesight is impaired, a nighttime support route is set that passes only on roads that are 5.5m or wider, have no more than two oncoming vehicles passing per minute, and have a gradient of 5% or less.

This allows the route setting unit 31 to identify roads that do not meet the nighttime illumination conditions or driving load conditions set in accordance with the driving ability indicated by the driving ability information 23 as roads that exceed the driver's driving ability at night, and to set a nighttime assistance route that does not pass through roads that exceed the driver's driving ability at night.
3A to 3C show an example in which nighttime illumination conditions and driving load conditions are set according to the driving ability at night based on the setting state of the nighttime support switch 16, the driver's age, and eyesight, but nighttime illumination conditions and driving load conditions according to the driving ability at night may also be set based on the driver's past driving behavior at night and the driver's driving experience.
The route setting unit 31 may also set a nighttime assistance route that does not pass through roads that lead to a junction with roads that do not meet the nighttime illumination and driving load conditions set in accordance with the driving ability indicated by the driving ability information 23 (i.e., roads that exceed the driver's driving ability at night).

2 , the driving assistance unit 32 determines whether the setting of the nighttime assistance switch 16 is on. For example, as shown in FIG. 3A , when the strength of the nighttime driving restriction imposed on the driver is set by the nighttime assistance switch 16, the driving assistance unit 32 may determine that the setting of the nighttime assistance switch 16 is on if the nighttime assistance switch 16 is not off (i.e., if the strength of the driving restriction is set to “weak” or “strong”).
When the nighttime support switch 16 is set to on, the driving support unit 32 supports the driver in driving to avoid driving the vehicle 1 on roads that exceed the driving ability indicated by the driving ability information 23.

For example, the driving assistance unit 32 may notify the driver of information encouraging the driver to depart with the vehicle 1 so that the driver does not drive the vehicle 1 after sunset.
For example, the driving assistance unit 32 may determine whether or not there is a possibility that the driver will drive the vehicle 1 until tomorrow morning. For example, if the destination of the vehicle 1 has been input into the route setting unit 31 by the driver or a passenger, it may be determined that there is a possibility that the driver will drive the vehicle 1 until tomorrow morning. Also, even if a destination has not been input into the route setting unit 31, and the current location of the vehicle 1 is not the driver's home, it may be determined that there is a possibility that the driver will drive the vehicle 1 until tomorrow morning. In this case, the route setting unit 31 may set the driver's home as the destination. The location of the driver's home may be registered in advance in the storage device 22, for example.
If the destination has not been input into the route setting unit 31 and the current location of the vehicle 1 is the driver's home, it may be determined that there is no possibility that the driver will drive the vehicle 1 until tomorrow morning.

If there is a possibility that the driver will drive the vehicle 1 between now and tomorrow morning, the driving assistance unit 32 may calculate the required time for the vehicle 1 to travel from the current position of the vehicle 1 to the destination.
The driving assistance unit 32 also obtains the sunset time for today. For example, the driving assistance unit 32 may obtain the earlier of the sunset time at the driver's home and the sunset time at the current location of the vehicle 1. The driving assistance unit 32 may obtain information about the sunset time from an external server device, for example, via the communication device 14, or may store information about the sunset time in advance in the storage device 22.

The driving assistance unit 32 may calculate a scheduled departure time that will allow the vehicle 1 to reach the destination before sunset, based on the time required for the vehicle 1 to travel from the current location to the destination and the sunset time for the day. The driving assistance unit 32 may notify the driver of the scheduled departure time or information urging the driver to depart with the vehicle 1 before the scheduled departure time.
For example, as information encouraging departure, the driving assistance unit 32 may notify the driver of information informing the driver of the scheduled departure time, or may notify the driver of information encouraging departure at the scheduled departure time or a predetermined time (e.g., 10 minutes) earlier than the scheduled departure time.
The driving assistance unit 32 may notify the driver of information encouraging departure by, for example, transmitting the information via the communication device 14 to an external terminal device 3 such as a mobile information terminal used by the driver, or may notify the driver of information encouraging departure by sounding the horn of the vehicle 1.

In addition, when the driver drives the vehicle 1 after sunset (i.e., when the driver drives the vehicle 1 at night), the driving assistance unit 32 executes night driving assistance control to assist the driver in driving at night.
In the nighttime driving assistance control, the driving assistance unit 32 assists the driver in driving the vehicle 1 along the nighttime assistance route set by the route setting unit 31. For example, the driving assistance unit 32 presents driving guidance to the driver so as to drive the vehicle 1 along the nighttime assistance route set by the route setting unit 31.
For example, the route setting unit 31 may display the nighttime assistance route set by the route setting unit 31 on a map on the display screen of the human-machine interface 15. In addition, the route setting unit 31 may output, from a speaker of the human-machine interface 15, audio guidance that provides voice guidance on turning right or left or going straight at an intersection.

Furthermore, for example, when a destination of the vehicle 1 is not set (i.e., when the driver does not use the driving route guidance function of the driving assistance device 10), the driving assistance unit 32 assists the driver in driving so as to prevent the driver from approaching a road that exceeds the driving ability indicated by the driving ability information 23. Furthermore, when the driver enters a road that exceeds the driving ability indicated by the driving ability information 23, the driving assistance unit 32 assists the driver in driving so as to prevent the driver from driving beyond the driving ability.
The same applies if the driver or passenger inputs a destination and the route setting unit 31 sets a driving route, but the driver intentionally or unintentionally deviates from the nighttime assistance route.

For example, the driving assistance unit 32 may determine whether the distance between the vehicle 1 and a road that exceeds the driving ability indicated by the driving ability information 23 is equal to or less than a predetermined value. In this specification, the term "distance" may refer to a spatial distance or a temporal distance. That is, the distance between a certain position A and another position B may be the distance between positions A and B, or the travel time taken for the vehicle 1 to travel between positions A and B.
When the distance between the road that exceeds the driving ability and the host vehicle 1 is equal to or less than a predetermined value, the driving assistance unit 32 may output an alarm from the display screen or speaker of the human-machine interface 15 to alert the driver that the driver has approached a road that exceeds the driving ability, to attract the driver's attention. Information guiding the driver to a road that matches the driver's driving ability may also be output from the human-machine interface 15. For example, a route away from the road that exceeds the driving ability may be displayed on a map on the display screen of the human-machine interface 15. Furthermore, audio guidance providing audio guidance on driving away from the road that exceeds the driving ability may also be output from the speaker of the human-machine interface 15.

Furthermore, for example, the driving assistance unit 32 may determine whether the vehicle 1 is heading toward a road that exceeds the driving ability indicated by the driving ability information 23. For example, the driving assistance unit 32 may determine whether the vehicle 1 is heading toward a road that exceeds the driving ability based on the current position and traveling direction of the vehicle 1, the road illuminance information, traffic volume information, and attribute information read from the map database 13, and the driving ability information 23.
When the vehicle 1 is heading towards a road that exceeds the driver's driving ability, the driving assistance unit 32 may output an alarm from the display screen or speaker of the human-machine interface 15 to inform the driver that the vehicle is approaching a road that exceeds the driver's driving ability and to draw the driver's attention.
Alternatively, information guiding the driver to a road appropriate for the driver's driving ability may be output from the human-machine interface 15. For example, a route away from roads that exceed the driver's driving ability may be displayed on a map on the display screen of the human-machine interface 15. Also, audio guidance providing voice guidance on driving away from roads that exceed the driver's driving ability may be output from a speaker of the human-machine interface 15.

In addition, the driving assistance unit 32 may determine whether the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the driving ability information 23 based on the current position of the vehicle 1, road illumination information, traffic volume information and attribute information read from the map database 13, and driving ability information 23.
When the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the driving ability information 23, the driving assistance unit 32 assists the driver in driving so as to reduce the driver's driving burden at night.
For example, when the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the driving ability information 23 , the driving assistance unit 32 may limit the vehicle speed of the vehicle 1 .

For example, the driving assistance unit 32 may limit the speed of the vehicle 1 to a speed equal to or lower than a predetermined speed set in advance.
For example, when the vehicle speed of the vehicle 1 is above a predetermined speed, the driving assistance unit 32 may suppress the acceleration force generated in the vehicle 1 so that the rate of increase in the speed of the vehicle 1 relative to the amount of depression of the accelerator pedal is smaller than when the vehicle speed is below the predetermined speed.
The driving assistance unit 32 may control the braking/driving force generating device 18 so that the vehicle speed of the host vehicle 1 is kept below a predetermined speed or so that the acceleration force is suppressed. Alternatively, the driving assistance unit 32 may output an audio message or a visual message from the human-machine interface 15 to urge the driver to drive at or below the predetermined speed.

For example, if the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the driving ability information 23, the driving assistance unit 32 may strengthen lane departure prevention control that prevents the vehicle 1 from deviating from the lane. For example, if the lane departure prevention control is a control that issues a warning to the driver when the lateral position of the vehicle 1 deviates from the center of the lane by a threshold or more, the threshold for issuing the warning may be reduced. For example, if the lane departure prevention control is a control that generates a steering force that prevents the vehicle 1 from deviating from the lane, the steering force generating device 19 may be controlled to reduce the lateral positional deviation of the vehicle 1 from the center of the lane.

Furthermore, for example, when the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the driving ability information 23, the driving assistance unit 32 may assist the driver in driving the vehicle 1 in a lane farther from the oncoming lane among multiple lanes on one side. For example, the driving assistance unit 32 may output a voice message or a visual message from the human-machine interface 15 to encourage the driver to drive in a lane farther from the oncoming lane.
For example, the driving assistance unit 32 may output an audio message or a visual message from the human-machine interface 15 encouraging the driver to change lanes to a lane farther from the oncoming lane, or may output an audio message or a visual message from the human-machine interface 15 discouraging the driver from changing lanes to a lane closer to the oncoming lane.

For example, if the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the driving ability information 23, the driving assistance unit 32 may alert vehicles around the vehicle 1 that the vehicle 1 is being driven on a road that exceeds the driver's driving ability at night.
For example, the driving assistance unit 32 may transmit information indicating that the vehicle 1 is being driven on a road that exceeds the driver's driving ability at night to another vehicle via the communication device 14, and alert the driver of the other vehicle.
The driving assistance unit 32 may also notify other vehicles that the vehicle 1 is being driven on a road that exceeds the driver's driving ability at night by displaying a message on the external display 17 .

(operation)
FIG. 4 is a flowchart illustrating an example of a driving assistance method according to the embodiment.
In step S1, the driving ability information acquisition unit 30 acquires driving ability information 23 relating to the driving ability of the driver.
In step S2, the route setting unit 31 and the driving support unit 32 determine whether the nighttime support switch 16 is off. If the nighttime support switch 16 is not off (step S2: N), the process proceeds to step S4. If the nighttime support switch 16 is off (step S2: Y), the process proceeds to step S3.
In step S3, the route setting unit 31 sets a normal driving route, after which the process ends.

In step S4, the route setting unit 31 and the driving assistance unit 32 determine whether or not a destination has been set by the driver or a passenger of the vehicle 1. If a destination has not been set (step S4: N), the process proceeds to step S6. If a destination has been set (step S4: Y), the process proceeds to step S5.
In step S5, the driving assistance unit 32 calculates the time required for the vehicle 1 to travel from the current position of the vehicle 1 to the destination. Based on the calculated time required and the sunset time of the day, the driving assistance unit 32 calculates a scheduled departure time that will allow the vehicle 1 to arrive at the destination before sunset. The process then proceeds to step S8.

On the other hand, if the driver or passenger has not set a destination for the vehicle 1 (step S4: N), the driving assistance unit 32 determines in step S6 whether the current location of the vehicle 1 is the home. If the current location of the vehicle 1 is the home (step S6: Y), the process ends. If the current location of the vehicle 1 is not the home (step S6: N), the process proceeds to step S7.
In step S7, the driving assistance unit 32 sets the home as the destination. Then, the driving assistance unit 32 calculates the required time for the vehicle 1 to travel from the current position of the vehicle 1 to the home. Based on the calculated required time and the sunset time for today, the driving assistance unit 32 calculates a scheduled departure time that will allow the vehicle 1 to arrive at the home before sunset. Then, the process proceeds to step S8.

In step S8, the driving support unit 32 determines whether the scheduled departure time calculated in step S5 or S7 has arrived. If the scheduled departure time has arrived (step S8: Y), the process proceeds to step S10. If the scheduled departure time has not yet arrived (step S8: N), the process proceeds to step S9.
In step S9, the driving assistance unit 32 determines whether the host vehicle 1 has already departed. If the host vehicle 1 has already departed (step S9: Y), the process proceeds to step S3. If the host vehicle 1 has not yet departed (step S9: N), the process returns to step S8.
In step S10, the driving support unit 32 notifies the driver of information urging the driver to depart for the destination set by the driver or passenger or for home.

In step S11, the driving assistance unit 32 determines whether the host vehicle 1 departs after the scheduled departure time. If the host vehicle 1 departs before the scheduled departure time (step S11: N), the process proceeds to step S3. If the host vehicle 1 departs after the scheduled departure time (step S11: Y), the process proceeds to step S12.
In step S<b>12 , the route setting unit 31 reads out the illuminance information, traffic volume information, and attribute information from the map database 13 .

In step S13, the route setting unit 31 sets a nighttime assistance route based on the driving ability information 23 acquired in step S1 and the illuminance information, traffic volume information, and attribute information read in step S12.
In step S14, the driving assistance unit 32 executes night driving assistance control to assist the driver in driving at night.

(Effects of the embodiment)
(1) The controller 20 executes the following processes: acquiring driving ability information 23, which is information on the driver's driving ability at night; reading illuminance information regarding the illumination of the road at night from the map information by referring to the map information based on the current position of the vehicle 1; and assisting the driver in driving based on a comparison between the acquired driving ability information 23 and the read illuminance information.
This allows the driver to be assisted in driving the vehicle 1 at night within the limits of their driving ability.

(2) The controller 20 may accept the setting of the destination, and based on the read illuminance information, set a driving route from the current position to the destination via roads with illuminance according to the driving ability indicated by the acquired driving ability information 23, and assist the driver in driving the vehicle 1 along the set driving route.
This prevents the driver from driving the vehicle 1 on roads that exceed the driver's driving ability at night.

(3) The controller 20 may display roads with nighttime illumination equal to or greater than a predetermined value on a map on a display screen that is visible to the driver.
This allows the driver to be informed of roads that are appropriate for their nighttime driving ability.
(4) When the driving ability indicated by the acquired driving ability information 23 is low compared to when the driving ability is high, the controller 20 may set a driving route that passes through roads with higher illumination at night.
This allows a driving route to be set according to the driver's driving ability at night.

(5) The controller 20 may acquire information regarding road traffic volume, and if the driving ability indicated by the acquired driving ability information 23 is low compared to when the driving ability is high, set a driving route that passes through roads or lanes with fewer oncoming vehicles.
This allows for the setting of a driving route that places less strain on the driver at night.
(6) The controller 20 acquires information regarding the gradient, curvature, or width of the road, and if the driving ability indicated by the acquired driving ability information 23 is low compared to when the driving ability is high, the controller 20 may limit the upper limit of the gradient, the upper limit of the curvature, or the lower limit of the width of the road included in the driving route.
This allows for the setting of a driving route that places less strain on the driver at night.

(7) The controller 20 may assist the driver in driving to avoid driving the vehicle 1 on roads that exceed the driving ability indicated by the acquired driving ability information 23.
This allows the driver to be assisted so that he or she can drive the vehicle 1 at night within the limits of his or her driving ability.
(8) The controller 20 may calculate the required time from the current location to the destination and prompt the driver to depart in the vehicle 1 at a scheduled departure time that will allow the driver to reach the destination before sunset or before the scheduled departure time.
This makes it possible to avoid driving the vehicle 1 on roads that exceed the driver's driving ability at night.

(9) The controller 20 determines whether the distance between the vehicle 1 and a road that exceeds the driving ability indicated by the acquired driving ability information 23 is less than a predetermined value, and if the distance is less than the predetermined value, the controller 20 may warn the driver or guide the driver to a road that corresponds to the driving ability indicated by the acquired driving ability information 23.
This makes it possible to prevent the vehicle 1 from entering roads that exceed the driver's driving ability at night.
(10) The controller 20 may determine whether the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the acquired driving ability information 23, and may limit the vehicle speed of the vehicle 1 if the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the acquired driving ability information 23.
This can assist the driver by reducing the driving burden on the driver at night.

(11) The controller 20 may determine whether the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the acquired driving ability information 23, and may alert vehicles around the vehicle 1 if the driver is driving the vehicle 1 on a road that exceeds the driving ability indicated by the acquired driving ability information 23.
This makes it possible to notify the drivers of vehicles around the vehicle 1 that the vehicle 1 is being driven on a road that exceeds the driver's driving ability at night.

1...Own vehicle, 2...Driving ability database, 3...External terminal device, 10...Driving assistance device, 11...Sensor, 12...Positioning device, 13...Map database, 14...Communication device, 15...Human-machine interface, 16...Nighttime assistance switch, 17...External display, 18...Braking/driving force generator, 19...Steering force generator, 20...Controller, 21...Processor, 22...Storage device, 23...Driving ability information, 30...Driving ability information acquisition unit, 31...Route setting unit, 32...Driving assistance unit

Claims (10)

A process of acquiring driving ability information, which is information on the driver's driving ability at night;
a process of reading illuminance information relating to nighttime illuminance of a road from map information by referring to the map information based on the current position of the vehicle;
a process of providing driving support to the driver based on a comparison between the acquired driving ability information and the read illuminance information;
The controller executes
The controller
Accept the destination setting,
Based on the read illuminance information, a driving route is set from the current location to the destination via roads with illuminance according to the driving ability indicated by the acquired driving ability information;
assisting the driver in driving the vehicle along the set travel route;
When the driving ability indicated by the acquired driving ability information is low compared to when the driving ability is high, the driving route is set to take place via roads with higher illumination at night .
A driving assistance method comprising: 2. The driving assistance method according to claim 1 , wherein the controller displays roads having a nighttime illumination level equal to or higher than a predetermined value on a map on a display screen visible to the driver. The controller
Obtain information about road traffic,
When the driving ability indicated by the acquired driving ability information is low compared to when the driving ability is high, the driving route is set to take roads or lanes with fewer oncoming vehicles.
3. The driving assistance method according to claim 1 or 2 . The controller
Obtaining information about the gradient, curvature or width of the road;
When the driving ability indicated by the acquired driving ability information is low compared to when the driving ability is high, limiting the upper limit of the gradient, the upper limit of the curvature, or the lower limit of the road width of the road included in the travel route.
4. The driving assistance method according to claim 1 , wherein the driving assistance method is a driving assistance method for a vehicle. The driving assistance method according to any one of claims 1 to 4 , characterized in that the controller assists the driver in driving the vehicle so as to avoid driving the vehicle on a road that exceeds the driving ability indicated by the acquired driving ability information. 6. The driving assistance method according to claim 5, wherein the controller calculates a required time from the current position to the destination, and prompts the driver to depart in the vehicle at a scheduled departure time that will allow the vehicle to reach the destination before sunset, or before the scheduled departure time . The controller
determining whether a distance between the vehicle and a road that exceeds the driving ability indicated by the acquired driving ability information is equal to or less than a predetermined value;
If the distance is equal to or less than a predetermined value, the driver is warned or guided to a road according to the driving ability indicated by the acquired driving ability information.
7. The driving assistance method according to claim 5 or 6 . The controller
determining whether the driver is driving the vehicle on a road that exceeds the driving ability indicated by the acquired driving ability information;
limiting the vehicle speed when the driver is driving the vehicle on a road that exceeds the driving ability indicated by the acquired driving ability information;
The driving assistance method according to any one of claims 5 to 7 . The controller
determining whether the driver is driving the vehicle on a road that exceeds the driving ability indicated by the acquired driving ability information;
When the driver is driving the vehicle on a road that exceeds the driving ability indicated by the acquired driving ability information, a notification is sent to vehicles around the vehicle.
The driving assistance method according to any one of claims 5 to 8 . a controller that executes a process of acquiring driving ability information, which is information on the driving ability of a driver at night; a process of reading illuminance information relating to the illuminance of a road at night from map information by referring to the map information based on the current position of the vehicle; and a process of assisting the driver in driving based on a comparison between the acquired driving ability information and the read illuminance information ;
The controller
Accept the destination setting,
Based on the read illuminance information, a driving route is set from the current location to the destination via roads with illuminance according to the driving ability indicated by the acquired driving ability information;
assisting the driver in driving the vehicle along the set travel route;
When the driving ability indicated by the acquired driving ability information is low compared to when the driving ability is high, the driving route is set to take place via roads with higher illumination at night .
A driving assistance device characterized by: