A system and method estimating a vehicle tire load includes a tire static load estimator estimating a static tire load using a tire attached TPMS sensor; a Kalman filter based tire deflection estimator estimating tire vertical deflection; a load variation estimator estimating the instantaneous load variation by using the tire vertical deflection information; and an output tire load estimator calculating an output load estimation mathematically by fusing the static tire load with the instantaneous load variation information. The tire deflection estimator includes a chassis accelerometer measuring a chassis vertical acceleration; and a hub accelerometer measuring a wheel hub vertical acceleration of the tire. A linear filter model receives as inputs the chassis vertical acceleration and the wheel hub vertical acceleration.

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 of the tire. The tire-side device may sense the detection signal and generate road surface data indicative of a road surface state appearing in a waveform of the detection signal. The tire-side device may transmit the road surface data. The vehicle-body-side system may perform bidirectional communication with the tire-side device and receive the road surface data. The vehicle-body-side system may determine the road surface state of a road surface on which the vehicle is traveling based on the road surface data.

A discloses system and method utilizes sensed oscillatory characteristics of a vehicle to detect a defect within a tire. The system utilizes information from sensors that are not disposed within a vehicle tire to detect tire defects. Information of oscillatory characteristics of the vehicle are analyzed to determine if the vehicle is operating as expected, or if a defect on the tire has changed the expected characteristics. Once a determination is made that a defect is present, an alert signal can be initiated to alert an operator that corrective action is required.

A system includes a computer including a processor and memory, the memory storing instructions executable by the processor. The instructions include instructions to detect body vibration of a vehicle body over time and to calculate wheel vibration of each wheel of the vehicle over time. In response to detection of body vibration under a first body vibration threshold, the computer calculates a baseline wheel vibration value for each wheel based on the calculated wheel vibration for each wheel, respectively. In response to detection of body vibration above a second body vibration threshold, the computer compares the calculated wheel vibration for each wheel with the baseline wheel vibration value of each wheels, respectively. The computer identifies a wheel imbalance in one of the wheels when a difference between the wheel vibration of the wheel and the baseline wheel vibration value of the wheel exceeds a wheel vibration threshold.