A method is disclosed for providing optimal compaction of various materials by controlling the vibration amplitude of an adjustable amplitude vibratory roller. The vibration amplitude is automatically reduced when excessively high jolting forces are sensed by transducers carried by the roller or its frame. The apparatus for carrying out the method includes a continuously adjustable eccentric element in the vibratory roller, at least two signal transducers mounted on the roller drum or frame and axially separated, to generate signals representing the vibrational movement of the roller. A regulating system responsive to the signals from the signal transducers reset the adjustable eccentric element to vary the vibration amplitude and provide optimal compaction.