Abstract: A method, comprising: measuring a rotational speed of a wheel of a vehicle, determining a longitudinal acceleration of the vehicle relative to a plurality of ambient terrestrial objects using a measurement system onboard the vehicle, determining a longitudinal speed of the vehicle relative to the plurality of ambient terrestrial objects using the measurement system, judging a slippage state of the vehicle using the longitudinal acceleration, and if a result of the judging indicates the vehicle is in a low-slippage state, estimating a coefficient of traction using the rotational speed and the longitudinal speed, wherein the measurement system is structured to radiate electromagnetic energy and to receive reflections of the electromagnetic energy reflected from the plurality of ambient terrestrial objects.