A control method for a vehicle, the control method being executable by at least one information processing device that includes a communication unit and a memory, the control method comprising: collecting vehicle information from the vehicle that includes the travelling history of the vehicle in a range of a communication data amount or a rate of communication that is allowed in communication with the vehicle, based on information about the communication data amount or the rate of communication and storing the vehicle information in the memory; predicting a traveling route of the vehicle based on the collected vehicle information; deriving a predicted fuel consumption of the vehicle based on the predicted travelling route, wherein the fuel consumption is derived based on a traveling state of other vehicles on the predicted travelling route; generating a control command based on the derived fuel consumption, wherein the control command is a fuel reduction command to reduce fuel consumption of the vehicle on the route; calculating an accuracy of the control command based on an information amount of the collected vehicle information and a relation of the vehicle information amount and the predicted value of the accuracy of the vehicle control stored in the memory, wherein the predicted value of the accuracy of the vehicle control increases with the increase in the data amount, and storing the predicted value of the accuracy of the vehicle control in the memory; regulating the control command based on the calculated accuracy, wherein regulating the control command includes decreasing the fuel reduction amount in response to a decrease in the calculated accuracy; and sending the fuel reduction command to the vehicle through the communication unit. collecting vehicle information from the vehicle that includes the travelling history of the vehicle in a range of a communication data amount or a rate of communication that is allowed in communication with the vehicle, based on information about the communication data amount or the rate of communication and storing the vehicle information in the memory; predicting a traveling route of the vehicle based on the collected vehicle information; deriving a predicted fuel consumption of the vehicle based on the predicted travelling route, wherein the fuel consumption is derived based on a traveling state of other vehicles on the predicted travelling route; generating a control command based on the derived fuel consumption, wherein the control command is a fuel reduction command to reduce fuel consumption of the vehicle on the route; calculating an accuracy of the control command based on an information amount of the collected vehicle information and a relation of the vehicle information amount and the predicted value of the accuracy of the vehicle control stored in the memory, wherein the predicted value of the accuracy of the vehicle control increases with the increase in the data amount, and storing the predicted value of the accuracy of the vehicle control in the memory; regulating the control command based on the calculated accuracy, wherein regulating the control command includes decreasing the fuel reduction amount in response to a decrease in the calculated accuracy; and sending the fuel reduction command to the vehicle through the communication unit.