Abstract: An alert system includes a display device, a display control unit, and a target recognition unit. The display control unit: when the number of targets recognized by the target recognition unit is equal to or more than an upper limit number, sets a display range of a surrounding icon as a whole circular area; and in a state where the number of targets is equal to or more than the upper limit number and the display range of the surrounding icon is set as the whole circular area, when the number of targets increases, reduces the size of the surrounding icon.

Abstract: The alert system includes a projection device, a display control unit, and a target object recognition unit. When a state changes from a state where a target object is not recognized by the target object recognition unit to a state where a target object is recognized by the target object recognition unit, the display control unit causes the projection device to output an alert display on a front window such that the length of the alert display is gradually shortened toward a position where a direction from an operator to the target object intersects with a front window.

Abstract: An alert system includes a display device, a display control unit, and a target recognition unit. The display control unit: when the number of targets recognized by the target recognition unit is equal to or more than an upper limit number, sets a display range of a surrounding icon as a whole circular area; and in a state where the number of targets is equal to or more than the upper limit number and the display range of the surrounding icon is set as the whole circular area, when the number of targets increases, reduces the size of the surrounding icon.

Abstract: A driving assistance apparatus includes a memory, and a processor coupled to the memory and configured to detect a state of surroundings of a mobile body, and reduce, when an object is detected during when a stationary sound is continuously output to a subject by using a plurality of sound sources that are arranged around the subject aboard the mobile body, output of the stationary sound toward the subject from a direction in which the object is detected.

Abstract: A driving assistance apparatus includes a memory, and a processor coupled to the memory and configured to detect a state of surroundings of a mobile body, and reduce, when an object is detected during when a stationary sound is continuously output to a subject by using a plurality of sound sources that are arranged around the subject aboard the mobile body, output of the stationary sound toward the subject from a direction in which the object is detected.