The purpose of the paper is to demonstrate the usefulness of the Dynamic Penetration Cone Index (DPCI) as an alternative for the control of sub grade surface. Correlating its results with other in place parameters such as load tests and the Penetration Index, the geotechnical characteristics of the sub grade surface can be estimated with great accuracy. The DPCI, gives consistent relationship when it is plotted against depth. Previous research concentrated on the relationship of the DCP with the CBR and SPT and the water content. This paper goes one step further introducing an index that better represent the geotechnical engineering properties of the subgrade surface. An extension of the use of the method for hard soils, such as the cemented sands of Asuncion, Paraguay, is also presented as an alternative to penetrability determinations with SPT equipment.