INFORMATION PROCESSING DEVICE, VEHICLE, INFORMATION PROCESSING METHOD, AND NON-TRANSITORY STORAGE MEDIUM

An information processing method includes determining whether at least one condition is satisfied, and calculating a feature quantity on flexibility of a tire (41; 42; 43; 44) when all of the at least one condition is satisfied. The at least one condition includes at least one of a first condition that an absolute value of an angular velocity (ω) of a steering wheel is smaller than a first reference value (ωref), and a second condition that an absolute value of a vector sum of vehicle accelerations (G) of the vehicle (1) including the steering wheel and wheels (400) each provided with the tire (41; 42; 43; 44) is smaller than a second reference value (Gref).