the vehicle body mounting locations of the suspension arms would be input to a vehicle control system and the overall driving condition of the vehicle may be determined by taking into consideration sensor values for engine rpms wheel rotation speed and the like together with estimated external force for the four wheels since external force exerted on the wheel 20 corresponds to the amount of relative displacement of the inner tubular fixture 26 and the outer tubular fixture 28 sensed in the suspension bushing 12 depending on the particular vehicle control system it may be possible to employ as the control signal therefor the unmodified sensor signal from the sensor 24 indicating relative displacement of inner tubular fixture 26 and outer tubular fixture 28 without the need to calculate external force on the wheel 20 as described hereinabove and amplifying the signal by means of an amp where necessary where the suspension system like that described hereinabove is employed external force acting on the wheel 20 can be sensed with substantially no lag time and with a high degree of accuracy in particular since an estimate of external force on the wheel 20 can be arrived at in the suspension bushing 12 which does not normally undergo relative displacement or rotation relative to the body as does the wheel 20 and which is sufficiently spaced away from the wheel 20 by means of the suspension member the sensing structure can be made simpler and with excellent robustness and durability while the invention has been shown and described in detail hereinabove with reference to certain preferred embodiments for illustrative purpose only it is to be understood that the invention is not limited to.