This study analyzes the flow of used tires from California across the international border into Mexico, primarily the state of Baja California and the San Luis Río Colorado region of Sonora. The study updates the August 2009 report The Flow of Used and Waste Tires in the California-Mexico Border Region to understand better the current challenges and opportunities presented by the commerce and movement of used tires from California to Mexico within the context of the dynamic border region. The report also reviews the disposition of waste tires in the region, along with an examination of the physical infrastructure and institutional framework for the management of waste tires. The report concludes with recommendations for addressing problems associated with used and waste tires in the cross-border trade.