may determine, for example, a consciousness state, an emotional state, and a health state of an occupant, e.g., the driver D.

Moreover, the occupant state determination unit 400 may detect a gaze direction of the driver.

To the occupant state determination unit 400, for example, a driver monitoring camera 401 and a seat surface pressure sensor 402 may be coupled.

FIG. 2 schematically illustrates arrangement of the driver monitoring camera 401 and the seat surface pressure sensor 402 in the driver assistance apparatus according to the embodiment.

The vehicle 1 may include a seat S on which the driver D is to be seated.

The seat S may include, for example, a seat cushion S1, a backrest S2, and a headrest S3.

The seat cushion S1 may be a seat surface portion on which the thighs, the buttocks, etc. of the driver D are to be placed.

The backrest S2 may be a portion that comes into contact with the back of the driver D and hold the upper body of the driver D.

The backrest S2 may protrude upward and diagonally rearward from the vicinity of a rear part of the seat cushion S1.

The headrest S3 may be disposed behind the head of the driver D. The headrest S3 may hold the head when the head moves backward.

The headrest S3 may be disposed to protrude upward from an upper end of the backrest S2.

The driver monitoring camera 401 may be an imaging device that captures an image of the driver D from the front of the vehicle.

The driver monitoring camera 401 may be disposed to include, in an imaging angle of view, the face of the driver D and the hands of the driver D in a state of holding a steering wheel SW.

The driver monitoring camera 401 may include, for example, a solid-state image sensor such as a complementary metal oxide semiconductor (CMOS) or a charge-coupled device (CCD), an optical system such as a lens group, and a driver circuit and an output processing circuit for the solid-state image sensor. The lens group may form a subject image on the solid-state image sensor.

The seat surface pressure sensor 402 may be provided at the seat cushion S1 and the backrest S2. The seat surface pressure sensor 402 may measure distribution of seat surface pressure to be received from the driver D by an upper surface of the seat cushion S1 and a front surface of the backrest S2.

Moreover, the occupant state determination unit 400 may include other sensors than these sensors.

For example, a sensor may be provided that acquires, for example, various kinds of biometric data, i.e., so-called vital signs, and an alcohol concentration in exhaled air. Non-limiting examples of the biometric data may include a heart rate, a body temperature, blood pressure, and a blood oxygen saturation level of the occupant.

The occupant state determination unit 400 may determine the gaze direction and the driving skill of the occupant, based on, for example, data regarding the environment around the vehicle, the travel state of the vehicle 1, and an occupant state. The gaze direction means a position of a central visual field. The data regarding the environment around the vehicle is recognized by the environment recognition unit 100. Non-limiting examples of the travel state of the vehicle 1 may include the data detected by the various sensors. The occupant state is detected by, for example, the driver monitoring camera 401 and the seat surface pressure sensor 402.

The occupant state determination unit 400 may estimate quality of the driving skill of the occupant based on, for example, changes in the gaze direction. The gaze direction means a direction from the eye toward the central visual field.

FIGS. 3A and 3B illustrate examples of a position history of the central visual field of the driver while the vehicle is traveling on a general road.

FIG. 3A illustrates data regarding a low skilled driver having relatively low driving skill, and FIG. 3B illustrates data regarding a highly skilled driver having relatively high driving skill.

In FIGS. 3A and 3B, the horizontal axes indicate an angle in a horizontal direction, and the vertical axes indicate an angle in a vertical direction.

As illustrated in FIGS. 3A and 3B, it can be seen that the gaze direction of the low skilled driver has a larger amount of the changes and higher frequency of the changes than the gaze direction of the highly skilled driver.

Some reasons for this may include: that the low skilled driver is not able to appropriately determine where to gaze at while driving; that the low skilled driver is not able to check the surrounding environment by a peripheral visual field while stabilizing the central visual field; and that the low skilled driver tends to excessively gaze at a region close to the vehicle.

In the meanwhile, it has been found that even the highly skilled driver sometimes has significant horizontal movement of the gaze direction because of, for example, poor visibility. Non-limiting examples with poor visibility may include a blind corner where an exit from a curved road is invisible, or an intersection with a road where someone may rush out.

Thus, the occupant state determination unit 400 may estimate the driving skill based on the vertical changes in the gaze direction of the occupant. The gaze direction means the direction toward the central visual field.

For example, the occupant state determination unit 400 may assume, for example, a variance and a standard deviation of a gaze position in the vertical direction, frequency of the vertical movement of gaze, an average value of an amount of the vertical movement of the gaze, as parameters. Thus, the occupant state determination unit 400 may estimate that the driving skill is low, in accordance with an increase in an average value of the parameters within a predetermined period of time.

Moreover, the occupant state determination unit 400 may estimate the driving skill with the use of multiple parameters in combination. For example, the occupant state determination unit 400 may compare a weighted sum of the multiple parameters with a predetermined threshold value to determine the driving skill.

The occupant state determination unit 400 may perform predetermined image processing on the images captured by the driver monitoring camera 401 to detect the vertical changes in the gaze direction of the occupant.

The image processing to detect the gaze direction may include, for example, detecting the center position of the eyeball and the center position of the pupil from the image of the eyes of the occupant, estimating a direction in which the pupil is directed from a deviation between the center position of the eyeball and the center position of the pupil, and assuming the estimated direction to be the gaze direction.

Instead of, or in addition to, the estimation of the gaze direction with the use of the position of the pupil described above, the occupant state determination unit 400 may estimate a skeleton state of the occupant from the images, and estimate the gaze direction from the skeleton state.

FIG. 4 schematically illustrates a skeleton of an occupant as viewed from front.

In general, when the occupant is mainly looking at something nearby, i.e., when the gaze direction lowers, the driver is getting nervous, or the shoulder of the driver tends to rise.

Thus, the occupant state determination unit 400 may estimate a distance L1 between a position of the eyes E of the skull B1 and an upper portion of the clavicle B2 based on the images captured by the driver monitoring camera 401, and estimate that the gaze direction lowers in accordance with a decrease in the distance L1.

In estimating the gaze direction in this way, positional relation between the eyes E and the clavicle B2 may sometimes change depending on, for example, individual differences, a degree of fatigue, a degree of nervousness of the driver.

To cope with this, for example, the occupant state determination unit 400 may initialize the parameters to be involved in a logic of the detection of the gaze direction when the vehicle 1 is stopped by, for example, a red light, and the gaze position of the occupant is high to visually recognize the traffic light.

FIG. 5 illustrates an example of a track of a vehicle when passing through a curved road.

In FIG. 5, a right curve in a case of left-side traffic is given as an example.

When driven by a highly skilled driver having relatively high driving skill, a vehicle V1 often takes a so-called “out-in-out” track to suppress a curvature of a cornering locus of the vehicle. In one example, the vehicle V1 may be the vehicle 1.

In this case, at a position P1 immediately before entering the curve, the vehicle is close to the left, or outer side, in the lane in preparation for the right curve.

Thereafter, the driver decelerates the vehicle by braking as necessary, and applies a rightward steering angle, to cause the vehicle V1 to start cornering. At a position P2 immediately after a start of cornering, the vehicle V1 has a yaw angle θ with respect to a direction of extension of the lane, to assume a posture in which the front of the vehicle body faces a clipping point CP. The clipping point CP is a position where the track is on innermost side of cornering.

When the vehicle V1 further advances to reach a position P3 where the vehicle V1 is about to pass through the clipping point, the track of the vehicle V1 is close to the innermost side within a lane width. Before or after this, the driver makes an accelerator operation, or an acceleration operation, while decreasing the steering angle, to allow the vehicle V1 to start to shift to a posture to escape toward an exit from the curve.

At a position P4 of a start of the escape, the vehicle V1 accelerates while decreasing the steering angle, and a lateral position in the lane gradually shifts to the outer side.

Thereafter, at a position P5 of an end of the escape after exiting from the curve, the steering angle becomes substantially zero, and the vehicle V1 continues to accelerate to a predetermined speed.

At this occasion, the lateral position in the lane is along the outer side of the curved road.

Driving by the highly skilled driver and driving by the low skilled driver are considered to have the following features, for example.

First, description is given of changes in the visual field.

FIG. 6 schematically illustrates an example of a visual field to be visually recognized by the driver when the vehicle enters the curve illustrated in FIG. 5.

Here, good visibility means, for example, a case with a sufficient visual field where the exit from the curve is visible.

Poor visibility means a case with a blind corner where the exit from the curve is invisible, and a case where there is a concern of a rush out.

For example, when checking a curve with good visibility, a highly skilled driver has the central visual field located at, for example, the lane-widthwise center, while checking the situation of the surroundings by the peripheral visual field.

Thereafter, during a period from immediately before the clipping point CP to just after passing through the clipping point CP, the central visual field is located on the inner side of the curve. During this period, the vehicle travels on the innermost side of the curve. FIG. 6 illustrates an example of the central visual field VP1 of the highly skilled driver at this occasion.

After passing through the clipping point CP, when the vehicle takes the posture to escape the curve, the central visual field often shifts to the outer side and moves to, for example, near the centerline of the lane.

In the case of poor visibility as well, the basic movement of the central visual field is similar to the case of good visibility. However, a highly skilled driver has relatively small movement of the central visual field, and tends to grasp the situation of the surroundings by the peripheral visual field.

In contrast, a low skilled driver has the central visual field displaced to the outer side, even in the case of a curve with good visibility, or when entering the curve. This may result in possibility that the track of the vehicle is insufficiently checked.

FIG. 6 illustrates an example of changes in a central visual field VP2 of a low skilled driver.

Moreover, a low skilled driver sometimes gazes at the inner side of the curve during the period from immediately before the clipping point CP to just after passing through the clipping point CP, even until the vehicle exits from the curve. Thus, a low skilled driver often fails in exiting from the curve in an ideal state while shifting the track toward the outer side.

In the case of a curve having poor visibility, such a feature becomes more remarkable.

Furthermore, for example, as illustrated in FIG. 5, when an oncoming vehicle V2 is present, a low skilled driver tends to gaze at the oncoming vehicle V2 too much, and fail in visually recognizing other regions sufficiently.

In general, a low skilled driver is easily distracted from the track of the vehicle by the situation of the surroundings, and tends to fail in concentrating on road conditions ahead. Thus, a low skilled driver may possibly fail in preparing for a driving operation to be made afterwards.

With regard to the steering operation, a highly skilled driver is able to travel along a curved road with a minimum steering angle and a minimum steering operation in accordance with the situation by taking the out-in-out track mentioned above.

In contrast, a low skilled driver is afraid of taking an outwardly protruding track, and therefore, tends to keep to the lane-widthwise inner side throughout from entering the curved road to exiting from the curved road. As a result, a curvature of the track increases and the lateral acceleration rate increases, or excessive deceleration becomes necessary. Furthermore, a low skilled driver is hasty in keeping to the inner side, resulting in an excessively high steering speed and the excessively large steering angle. This contributes to a concern of lane deviation toward an opposite lane or coming close to an obstacle such as a curbstone.

With regard to a speed control, e.g., an acceleration operation and a deceleration operation, a highly skilled driver is able to decelerate to an appropriate speed before starting steering in entering the curve. A highly skilled driver is able to maintain an appropriate vehicle speed suitable for the steering angle, road surface conditions, and the surrounding environment, etc., from entering the curve to passing through the clipping point CP.

Moreover, in exiting from the curved road, a highly skilled driver is able to accelerate the vehicle by making an appropriate acceleration operation that does not disturb the behavior of the vehicle 1.

In contrast, a low skilled driver has low accuracy of a determination as to a distance to the entrance to the curved road or a curvature of the curved road, in entering the curved road. It follows that the low skilled driver may sometimes make sudden braking immediately before entering the curved road, or enter the curve at an excessively high speed.

Moreover, during the period from entering the curved road to passing through the clipping point CP, the low skilled driver may make an unnecessary deceleration operation or an unnecessary acceleration operation, resulting in a concern that the behavior of vehicle is disturbed.

Furthermore, when the vehicle exits from the curved road, a low skilled driver may become so hasty in acceleration and make an excessive acceleration operation, resulting in a concern that the behavior of the vehicle is disturbed.

To allow for stable travel regardless of the quality of the driving skill in traveling along the curved road, the driver assistance apparatus according to the embodiment may make different driver assistance controls in accordance with the skill of the driver, as described below.

FIG. 7 is a flowchart illustrating start-up operation in the vehicle including the driver assistance apparatus according to the embodiment.

This processing may be performed, for example, every driving cycle after a main power supply of the vehicle 1 is turned on, or the ignition switch is turned on.

Here, the driving cycle refers to a period of time from the turning on of the main power supply of the vehicle 1 to turning off of the main power supply after travel to a destination.

In the following, description is given in the order of steps.

Step S01: Vehicle Calibration

The driver assistance control unit 200 may perform vehicle calibration, in cooperation with the vehicle state recognition unit 340. The vehicle calibration includes calibration and initialization of parameters related to the performance of the vehicle 1.

The vehicle calibration is carried out, for example, after a start of the driving cycle until all the following conditions are satisfied:

- (a) the vehicle has passed through right-angle intersections accompanied by a stop in response to a traffic signal or a pause, a predetermined number of times (for example, three times) or more;
- (b) a travel distance has reached a predetermined distance (for example, 4 km); and
- (c) a continuous travel distance at a predetermined speed (for example, 40 km/h) is a predetermined distance (for example, 200 m) or more.

Non-limiting examples of the parameters to be calibrated may include the spring constants and the damping characteristics of the suspension and the tire of each wheel, and a loading state of the vehicle, and load distribution to each wheel. The loading state of the vehicle may include, for example, a loading weight and the total weight of the vehicle.

It is to be noted that, until an end of the calibration, values acquired in the previous driving cycle may be used.

Thereafter, the flow may be allowed to proceed to step S02.

Step S02: Occupant Calibration

The occupant state determination unit 400 may determine the quality of the driving skill of the occupant, e.g., the driver.

At this occasion, the occupant state determination unit 400 may determine whether or not the driver is in an unsuitable state for driving. Non-limiting examples of the unsuitable state for driving may include being in a poor physical condition, having unsuitable emotions for driving, and having taken alcohol. Having unsuitable emotions for driving may include, for example, being distracted, anxious, confused, frustrated, or angry. When the driver is in the unsuitable state for driving, the occupant state determination unit 400 may give a warning to the occupant or give a notification to the base station provided outside through the driver assistance control unit 200.

Such occupant calibration may be made at any time during the driving cycle, for example, every time a duration of travel at a predetermined vehicle speed, e.g., 20 km/h, or more reaches predetermined time, e.g., 15 minutes.

It is to be noted that, until an end of the calibration, values acquired in the previous driving cycle may be used.

Thereafter, the flow may be allowed to proceed to step S03.

Step S03: Start to Compare Current Position with Map Data

The environment recognition unit 100 may start to detect the current position of the vehicle with the use of the positioning device 150.

The environment recognition unit 100 may make comparison between the current position of the vehicle and the map data accumulated in the high-precision map database 140, based on the detected current position, and grasp data regarding, for example, road shapes, e.g., the lane shapes, around the vehicle.

Thereafter, the flow may be allowed to proceed to step S04.

Step S04: Start to Acquire Vehicle Speed

The driver assistance control unit 200 may acquire, from the brake control unit 330, data regarding the vehicle speed calculated from an output of the vehicle speed sensor 332.

Thereafter, the flow may be allowed to proceed to step S05.

Step S05: Start to Detect Vehicle Position and Angle

The environment recognition unit 100 may start to detect the lateral position in the lane along which the vehicle 1 travels, and a deflection angle, or an angle, of a longitudinal direction of the vehicle body of the vehicle 1 with respect to the direction of extension of the lane, with the use of the output of each sensor. The lateral position means a vehicle-widthwise position.

Thereafter, the flow may be allowed to proceed to step S06.

Step S06: Start to Detect Gaze Direction

The occupant state determination unit 400 may start to detect the gaze direction of the driver based on the images captured by the driver monitoring camera 401. The gaze direction means the direction toward the central visual field,

Thereafter, the flow may be allowed to proceed to step S07.

Step S07: Start to Detect Vehicle Behavior

The brake control unit 330 may start to detect the longitudinal, vehicle-widthwise, and vertical acceleration rates in a translational direction, and the yaw rate, each acting on the vehicle body, with the use of outputs of the acceleration rate sensor 333 and the yaw rate sensor 334.

Thereafter, the flow may be allowed to proceed to step S08.

Step S08: Start to Detect Oncoming Vehicle

The environment recognition unit 100 may start to detect other vehicles, e.g., an oncoming vehicle V2, traveling in a direction in which they approach the vehicle, along an opposite lane adjacent to the lane along which the vehicle travels, with the use of, for example, the visible light camera device 110.

Thereafter, the series of start-up processing may be ended.

After the end of the start-up processing described above, the vehicle 1 may start the following control as the vehicle 1 approaches the curved road.

FIG. 8 is a flowchart illustrating a control in entering a curved road, in the driver assistance apparatus according to the embodiment.

In the following, description is given in the order of steps.

Step S11: Determine Whether Curve is Approaching

The environment recognition unit 100 may determine whether or not the curved road is approaching ahead of the vehicle, based on the position of the vehicle detected by the positioning device 150 and the map data accumulated in the high-precision map database 140.

When the curved road is approaching until estimated arrival time is equal to or less than a predetermined value, the flow may be allowed to proceed to step S12. Otherwise, step S11 may be repeated.

Step S12: Start Priority Management of Vehicle Position and Angle

The environment recognition unit 100 may start priority management that includes detecting the lateral position in the lane of the vehicle and the angle of the longitudinal direction of the vehicle with respect to the direction of extension of the lane, with higher temporal resolution and higher spatial resolution than usual.

Thereafter, the flow may be allowed to proceed to step S13.

Step S13: Start Priority Management of Gaze Direction

The occupant state determination unit 400 may start priority management that includes detecting the gaze direction of the driver, with higher temporal resolution and higher spatial resolution than usual.

Thereafter, the flow may be allowed to proceed to step S14.

Step S14: Start Priority Management of Vehicle Behavior

The driver assistance control unit 200 may start priority management that includes detecting the longitudinal, vehicle-widthwise, and vertical acceleration rates in the translational direction, and the yaw rate, each acting on the vehicle body, with higher temporal resolution and higher spatial resolution than usual.

Thereafter, the flow may be allowed to proceed to step S15.

Step S15: Start Priority Management of Oncoming Vehicle

The environment recognition unit 100 may start priority management that includes detecting an oncoming vehicle, with higher temporal resolution and higher spatial resolution than usual.

Thereafter, the flow may be allowed to proceed to step S16.

Step S16: Estimate Deceleration Potential

The driver assistance control unit 200 may estimate a deceleration potential, based on the result of the vehicle calibration mentioned above, the current vehicle speed, and a longitudinal gradient of the lane along which the vehicle travels. The deceleration potential is a parameter related to possibility that the vehicle is able to safely decelerate to a predetermined vehicle speed by the time of the entry to the curved road. The deceleration potential may be set to lower in accordance with an increase in the loading weight of the vehicle, an increase in a degree of deviation of the load distribution to the side on which the front wheels are disposed or the side on which the rear wheels are disposed, an increase in the vehicle speed, and an increase in a downward gradient of a road surface.

Thereafter, the flow may be allowed to proceed to step S17.

Step S17: Determine Driver's Skill

The occupant state determination unit 400 may determine whether the driver is a highly skilled driver having relatively high driving skill or whether the driver is a low skilled driver having relatively low driving skill.

It is possible to determine the driving skill based on, for example, as described above, the vertical changes in the gaze direction during normal travel.

Moreover, the skill of the driver may be determined in accordance with the travel state during previous travel along the curved road. For example, in entering the curved road in an initial stage at the start of cornering at the position P2 in FIG. 5, when the yaw angle θ of the vehicle with respect to the lane is directed toward the clipping point CP, the occupant state determination unit 400 may determine that the driver is a highly skilled driver. When the yaw angle θ of the vehicle with respect to the lane is close to a parallel direction to the lane, the occupant state determination unit 400 may determine that the driver is a low skilled driver.

Thereafter, the series of processing may be ended.

Description now moves on to detailed contents of the driver assistance control in traveling along the curved road.

First, description is given of processing to be carried out when the determination is made in step S17 described above that the driver is a highly skilled driver.

FIG. 9 is a flowchart illustrating the driver assistance control in traveling along the curved road when the determination is made that the driver is a highly skilled driver, in the driver assistance apparatus according to the embodiment.

In the following, description is given in the order of steps.

Step S21: Determine Whether Position of Entering is on Outer Side

The environment recognition unit 100 may determine whether or not the lateral position in the lane is within a predetermined outer region when the vehicle is at a predetermined distance from the entrance to the curved road. The outer region is set on the outer side of the curved road.

When the lateral position in the lane is within the outer region, the flow may be allowed to proceed to step S23. Otherwise, the flow may be allowed to proceed to step S22.

Step S22: Determine Whether Position of Entering is at the Center

The environment recognition unit 100 may determine whether or not the lateral position in the lane is within a predetermined center region when the vehicle is at the predetermined distance from the entrance to the curved road. The center region is set at the center portion of the lane.

When the lateral position in the lane is within the center region, the flow may be allowed to proceed to step S25. Otherwise, assuming that the vehicle is entering the curved road on the inner side, the flow may be allowed to proceed to step S30.

Step S23: Steering Assistance Normal Control

The electric power steering control unit 310 may set correlation between an output of the torque sensor 312 and the assistance force, i.e., the output of the motor 313, to a state for the normal travel.

Thereafter, the flow may be allowed to proceed to step S24.

Step S24: Accelerator Normal Control

The power unit control unit 320 may set correlation between the amount of operation of the accelerator pedal and the request torque to be used in the control of the travel power source, to a state for the normal travel.

Thereafter, the series of processing may be ended.

As described, when the highly skilled driver enters the curved road on the outer side, the driver takes the so-called out-in-out track. This often causes generation of a relatively large yaw angle θ (refer to FIG. 5) in entering the curved road, to allow the vehicle body to be directed toward the clipping point CP with respect to the direction of the lane.

Here, when the yaw angle θ of the vehicle with respect to the direction of the lane is not sufficiently large in entering the curved road at a position corresponding to, for example, the position P2 in FIG. 5, there is possibility that there has been an error in the estimation of the driving skill of the driver or possibility that the driver has made a driving mistake. Thus, it is possible to make, for example, a control of automatically braking to reduce the vehicle speed, a steering force reduction control, or a yaw moment generation control. The steering force reduction control includes increasing the assistance force by the power steering device to promote the steering operation in a direction in which the steering angle increases. The yaw moment generation control includes generating a yaw moment in the vehicle to allow the vehicle to pass through the inner side of the lane when the vehicle passes through the clipping point CP.

Step S25: Slow Deceleration Control in Entering

The driver assistance control unit 200 may give a command to the brake control unit 330, and make a deceleration control in entering. The deceleration control in entering includes automatically reducing the vehicle speed of the vehicle 1 to a predetermined target vehicle speed by the time of the entry to the curved road.

The target vehicle speed may be set in accordance with, for example, the curvature of the curved road recognized by the environment recognition unit 100 with the use of the visible light camera device 110 or the high-precision map database 140.

A deceleration rate, or the braking force, in the deceleration control in entering may be controlled to be suppressed in accordance with a decline in the deceleration potential described above.

Thereafter, the flow may be allowed to proceed to step S26.

Step S26: Steering Assistance Suppression Control; Weak

The driver assistance control unit 200 may give a command to the electric power steering control unit 310, and make a steering assistance suppression control, i.e., a steering force increase control. The steering assistance suppression control includes reducing the output of the motor 313 with respect to the output of the torque sensor 312, i.e., an amount of assistance by the electric power steering device.

This causes an increase in an operation force, or the steering force, when the driver makes the steering operation in the direction in which the steering angle increases, and an increase in a steering retention force to maintain the steering angle. Hence, it is possible to prevent an application of an excessive steering angle by an inappropriate steering operation, leading to prevention of lane deviation toward the inner side and an abnormal approach to the oncoming vehicle V2.

Thereafter, the flow may be allowed to proceed to step S27.

Step S27: Accelerator Suppression Control

The power unit control unit 320 may carry out an accelerator suppression control. The accelerator suppression control includes changing the correlation between the amount of operation of the accelerator pedal and the request torque to cause suppression of an output of the travel power source as compared to the normal state, to reduce the request torque for the same amount of operation.

Hence, it is possible to prevent the vehicle from becoming unstable because of the generation of an excessive driving force even when the skill of the driver is lower than originally estimated.

Thereafter, the flow may be allowed to proceed to step S28.

Step S28: Determine Whether Vehicle has Shifted toward Inner Side

The driver assistance control unit 200 may determine, based on an output of the environment recognition unit 100, whether or not the track of the vehicle 1 has shifted toward the inner side of the curved road by a predetermined amount or more.

For example, when the yaw angle θ of the vehicle 1 is on the inner side with respect to the direction of the lane and is equal to or larger than a predetermined threshold value, or when the lateral position in the lane of the vehicle 1 has shifted toward the inner side by the predetermined amount or more, the flow may be allowed to proceed to step S29. Otherwise, the series of processing may be ended. The inner side with respect to the direction of the lane means the side on which the clipping point CP is disposed.

Step S29: Steering Assistance Suppression Control; Strong

The driver assistance control unit 200 may give a command to the electric power steering control unit 310, and make the steering assistance suppression control; strong, i.e., the steering force increasing control; strong. The steering assistance suppression control; strong includes reducing the amount of assistance by the electric power steering device to an even smaller amount than the steering assistance suppression control; weak in step S26.

This causes a greater increase in the steering force. Hence, after the driver makes the steering control to increase the steering angle to cause the track to shift toward the inner side, it is possible to prevent, for example, the lane deviation by further increasing the steering angle because of an erroneous operation.

Thereafter, the series of processing may be ended.

Step S30: Deceleration Control in Entering