DRIVING DIAGNOSTIC DEVICE, DRIVING DIAGNOSTIC METHOD, AND STORAGE MEDIUM

A driving diagnostic device includes a processor. The processor acquires vehicle operation information including a direction indicator signal indicating an operation of a direction indicator of a vehicle and a yaw rate of the vehicle from a sensor mounted on the vehicle, determines that an event indicates a lane change by the vehicle when the vehicle operation information satisfies a predetermined condition, and performs evaluation of a driving operation of the vehicle during a period of the event.