Completed in 2014, the U.S. Highway 101 / 13th Street Bridge Overcrossing project involved the construction of new southbound on/off ramps, construction of additional traffic lanes, and retaining walls. This city funded project is along U.S. Highway101, and extends from the 13th Street overcrossing to State Route 46 East in Paso Robles. The 13th Street Overcrossing Bridge was retrofitted by constructing two retaining walls at the west abutment. This effort provides additional room for traffic on the overcrossing structure. During the design phase of the project, Earth Systems prepared a preliminary foundation report (PFR) and a foundation report (FR) for the augmentation of the 13th Street overcrossing. The team prepared a materials report for the widening of the highway. Earth Systems also conducted soil sampling and analysis along approximately 6,000 feet of the highway to assess the potential for Aerially Deposited Lead (ADL). Laboratory analysis of 60 samples revealed the presence of several ‘hot spots’ that required more detailed assessment. Earth Systems provided materials testing in accordance with Caltrans standards.