Driving assist system

1. A driving assist system that assists driving of a vehicle,

the driving assist system comprising:

a processor configured to execute driving assist control that has a plurality of control modes associated with a plurality of scenes on a one-to-one basis; and

a memory device in which driving environment information indicating a driving environment for the vehicle and plural pieces of scene description information respectively defining the plurality of scenes are stored, wherein

the processor recognizes a scene corresponding to the driving environment among the plurality of scenes as a subject scene, based on the driving environment information and the plural pieces of scene description information,

a selected control mode is one associated with the subject scene among the plurality of control modes,

selected scene description information is one defining the subject scene among the plural pieces of scene description information and indicates parameters used in the driving assist control of the selected control mode,

the processor executes the driving assist control of the selected control mode based on the parameters indicated by the selected scene description information, and switches the selected control mode by switching the selected scene description information, and

when the subject scene changes from a first scene to a second scene, the processor notifies an occupant of the vehicle of switching of the selected control mode before switching the selected scene description information and the selected control mode,

wherein

when notifying the occupant of the switching, the processor requests the occupant for approval of the switching,

when the occupant approves the switching, the processor executes the switching,

when the occupant refuses the switching, the processor requests a driver of the vehicle to perform manual driving, and

when the occupant refuses the switching, the processor beforehand switches the selected scene description information during execution of the manual driving and notifies the driver that resumption of the driving assist control is possible.

2. The driving assist system according to claim 1 , wherein

at least a part of the parameters indicated by the selected scene description information regarding the second scene is not indicated by the selected scene description information regarding the first scene.

3. The driving assist system according to claim 1 , wherein

when the subject scene changes from a third scene to a fourth scene, the processor executes the switching without beforehand notifying the occupant of the switching of the selected control mode.

4. The driving assist system according to claim 3 , wherein

all of the parameters indicated by the selected scene description information regarding the fourth scene are included in the parameters indicated by the selected scene description information regarding the third scene.

5. The driving assist system according to claim 1 , wherein

each of the plurality of scenes is defined by a configuration of the vehicle and a moving object in a predetermined space around the vehicle.

6. The driving assist system according to claim 5 , wherein

the parameters include:

vehicle parameters including a lane in which the vehicle exists, a position of the vehicle, and a velocity of the vehicle; and

moving object parameters including a lane in which the moving object exists, a position of the moving object, and a velocity of the moving object.