Abstract: Estimation of the degree of compaction of a bed when using a compacting machine employs an oscillatory principle. The oscillatory compacting machine is arranged to act on the bed by gravitational force and rapidly alternating horizontal force. The method uses a recorded signal from a horizontally mounted sensor connected to the bearing of the roller drum. The system for performing this method, utilizes a processor to calculate results which are presented by a display unit. Beside the acceleration sensor another sensor and a switch are used in order to enable calculation by the processor of different kinds of averages of the compaction meter value and also for determination of travel speed.