A main objective in all geotechnical site investigations is to determine the type, extent, and properties of the geologic materials in as much detail as possible within the constraints of the given site conditions and project budget. Cone penetrometers (CPTs), specifically piezocones (CPTUs), offer a site investigation tool that can effectively identify the behavioral type and extent of tested stratigraphy, and provide unparalleled profiling ability, with CPTU response times typically sufficiently fast to identify very thin layers (< 5 mm) (Lunne et al., 1997). Accurate geostratification and classification are paramount to successful geotechnical engineering practice, as the soil layering and classification often serve as the basis for all subsequent analyses and calculations. The values of CPT data are functions of a number of fundamental soil characteristics, and as such, the variations in measured response can be used to identify both the layering and properties of tested soils. The interface behavior of soils is known to vary as both a function of soil type and the contacting interface properties. Most notably soil – continuum interface response is known to be primarily affected by the angle of internal friction of the soil and the surface roughness of the counterface material. The multi friction attachment devices recently developed at Georgia Tech have the ability to provide in situ measurements of interface behavior across the full range of typical surface roughness properties encountered in geotechnical engineering and for all soil conditions amenable to penetrometer investigations. This paper analyzes the friction data obtained for the various geologic conditions tested to date, to investigate whether the use of the multi friction attachment (MFA) and multi piezo friction attachment (MPFA) can provide data allowing for improved in situ soil classification through the use of fundamental soil-interface behavior concepts.