predict, as a user action, an action of a first user in a certain period, including parking a vehicle in a parking lot shared by a plurality of users including the first user and a second user;

generate proposal data for proposing an action plan in the certain period based on an obtained prediction result and information on the parking lot in the certain period; and

output the generated proposal data, wherein:

the prediction result includes a first estimated time when the first user is expected to leave the parking lot with the vehicle;

the information on the parking lot includes an estimated congestion status of an exit of the parking lot or a road around the parking lot at the first estimated time; and

the controller is configured to include, in the action plan, an action of leaving the parking lot with the vehicle at a leaving time different from the first estimated time under a condition that the estimated congestion status exceeds a reference congestion level.