ROAD SURFACE STATE DETERMINATION DEVICE

A road surface state determination device includes a tire-side device and a vehicle-body-side system. The tire-side device is attached to each of a plurality of tires included in a vehicle. The vehicle-body-side system is included in a body of the vehicle. The tire-side device may output a detection signal corresponding to a magnitude of vibration applied to the tire. The tire-side device may extract data items of a road surface state indicative of the vibration of the tire during one rotation of the tire from the detection signal. The tire-side device may generate road surface data. The tire-side device may transmit the road surface data. The vehicle-body-side system may receive the road surface data. The vehicle-body-side system may determine the road surface state based on the road surface data.