Vehicle system and vehicle

1. A vehicle system comprising:

a warning device including

at least one of a vibration generation device configured to generate a vibration and a sound output device configured to output a sound, and

a display projection device configured to project a display on a display area of a head-up display provided in a vehicle; and

at least one electronic control unit configured to

present a light stimulus to a driver of the vehicle by using the head-up display when a change in a traffic environment is detected ahead of the vehicle, while the vehicle is performing autonomous driving,

determine whether the driver is facing forward,

determine whether the driver holds a steering wheel, and

cause the warning device to

perform a first warning, when it is determined that the driver is not facing forward while the light stimulus is being presented, the first warning being either the vibration generated by the vibration generation device or the sound output by the sound output device, and

perform a second warning, when it is determined that the driver does not hold the steering wheel before a first predetermined time elapses after the first warning is started, the second warning including the vibration generated by the vibration generation device and the sound output by the sound output device.

2. The vehicle system according to claim 1 , wherein

the at least one electronic control unit is configured to

increment a number of re-holding times, when it is determined that the driver faces forward before a second predetermined time elapses after the second warning is started or when it is determined that the driver holds the steering wheel before the second predetermined time elapses after the second warning is started, and

output a signal for terminating the autonomous driving of the vehicle to an autonomous driving electronic control unit, when number of re-holding times while the light stimulus is being presented, is equal to or greater than a threshold, the autonomous driving electronic control unit being provided in the vehicle and being configured to perform the autonomous driving of the vehicle.

3. The vehicle system according to claim 2 , wherein

the at least one electronic control unit is configured to decelerate the vehicle or stop the vehicle when it is determined that the driver does not hold the steering wheel before the second predetermined time elapses after the second warning is started.

4. The vehicle system according to claim 1 , wherein

the at least one electronic control unit is configured to decelerate the vehicle or to stop the vehicle when it is determined that the driver does not hold the steering wheel before a second predetermined time elapses after the second warning is started.

5. The vehicle system according to claim 1 , further comprising

a driver monitor camera, wherein

the at least one electronic control unit is configured to detect whether the driver is facing forward by using the driver monitor camera.

6. The vehicle system according to claim 1 , wherein

the second warning has a stimulus intensity higher than the stimulus intensity of the first warning.

7. The vehicle system according to claim 1 , wherein the vibration generation device includes a weight and motor configured to rotate the weight to generate the vibration, and wherein the sound output device includes a speaker configured to output the sound.

8. A vehicle comprising:

a sensor configured to detect a change in a traffic environment ahead of the vehicle;

a head-up display including a display projection device, the display projection device being configured to present a light stimulus to a driver of the vehicle by projecting a display on a display area of the head-up display based on a detection result of the sensor;

a warning device including at least one of a vibration generation device and a sound output device, the warning device configured to output at least one of a vibration generated by the vibration generation device and a sound output by the sound output device; and

at least one electronic control unit configured to

cause the display projection device to present the light stimulus,

determine whether the driver is facing forward,

cause the warning device to perform a first warning when it is determined that the driver is not facing forward while the light stimulus is being presented,

determine whether the driver holds a steering wheel, and

cause the warning device to perform a second warning, when it is determined that the driver does not hold the steering wheel before a first predetermined time elapses after the first warning is started, cause the warning device to perform a second warning, when it is determined that the driver does not hold the steering wheel before a first predetermined time elapses after the first warning is started, wherein the second warning:

has a stimulus intensity higher than the stimulus intensity of the first warning, or

is performed to stimulate a number of senses of the driver greater than a number of senses that the first warning is performed to stimulate.

9. The vehicle according to claim 8 , further comprising

an autonomous driving electronic control unit configured to perform autonomous driving of the vehicle, wherein

the at least one electronic control unit is configured to

cause the autonomous driving electronic control unit to perform the autonomous driving of the vehicle,

increment the number of re-holding times when it is determined that the driver faces forward before a second predetermined time elapses after the second warning is started or when it is determined that the driver holds the steering wheel before the second predetermined time elapses after the second warning is started, and

output a signal for terminating the autonomous driving of the vehicle to the autonomous driving electronic control unit when the number of re-holding times is equal to or greater than a threshold.

10. The vehicle according to claim 8 , wherein

the at least one electronic control unit is configured to decelerate the vehicle or to stop the vehicle when it is determined that the driver does not hold the steering wheel before a second predetermined time elapses after the second warning is started.

11. The vehicle according to claim 8 , wherein the senses of the driver include a visual sense and a non-visual sense.

12. The vehicle according to claim 8 , wherein the vibration generation device includes a weight and motor configured to rotate the weight to generate the vibration, and wherein the sound output device includes a speaker configured to output the sound.