James Cox & Sons, based in Colfax, California designs & manufactures equipment for asphalt, concrete and soil testing which conform to various ASTM, AASHTO & Californian specifications. James Cox & Sons manufactures & supplies full product range of Superpave Equipment®, including Superpave Gyratory Compactor, Hamburg Wheel Tracker, Four Point Bending Machine, UTM's, RTFO and Texas Overlay Tester.