The San Luis Obispo Airport Runway 11-29 Extension realigned Santa Fe road with the construction of a 1400-foot long embankment, entailing fills of up to 20 feet, to support a northwesterly extension of the runway. The majority of the previous road alignment was abandoned; two connector roads extending east from the new alignment were also constructed to provide access to existing industrial parcels. Earth Systems performed a soils engineering investigation involving subsurface exploration, soils sampling, laboratory testing. Primary geotechnical concerns were soft upper soils, the presence of fill and stockpiled AC/PCC rubble, the potential for instability during grading, low R-values and erodibility of the site soils. To mitigate these concerns, Earth Systems provided geotechnical recommendations for site preparation, grading, utility trenches, asphalt concrete pavement sections, drainage, and observation and testing during construction. During roadway and runway construction, the Earth Systems team performed compaction testing of base material, onsite sampling of asphalt concrete, and testing for air voids, stability, flow and relative compaction.