An information processing system includes a vehicle and a server. The vehicle generates a plurality of captured still images in which scenery outside the vehicle is captured, and acquires position information of the vehicle. The vehicle or the server executes a detection process of detecting a predetermined object in a captured moving image that includes each of the plurality of captured still images as a frame, calculates the number of times that the predetermined object is detected of a section of a predetermined amount of time while changing a position of the section, and determines position information of a candidate start point of a traffic disturbance site on the road based on the position information of the vehicle at a time when at least one captured still image included in the section when the number of times that the predetermined object is detected exceeds a first reference number, is generated.