Pioneers in Asphaltic & Unbound Materials Testing

About us

James (Jim) Cox initially worked as a design engineer developing products to test asphalt for highway construction. Jim started out working for the Californian highway materials and research division. Jim left to set up his own business, originally working from his garage in Sacramento. Later Jim set up “James Cox & Sons” based in Colfax, California, a professional business that is globally renowned for innovation and quality. The business has been successfully trading for over 30 years. Cox & Sons was selected by The University of California at Berkeley (UCB) to design and manufacture the prototype shear testing system for the federal Strategic Highway Research Program (SHRP). SHRP was initiated to develop standards for road construction in this country. The original testing system is still in use at the Richmond Field Station (UCB). Over the years, James Cox & Sons has developed a line of products for asphalt, concrete and soil testing which conform to various ASTM, AASHTO and Californian specifications. Cox & Sons has built a reputation for manufacturing the highest quality equipment utilizing the finest materials and latest technology. We integrate all of these factors to provide top-of-the-line systems for a complete customer orientated solution. All of our products are designed and fabricated with care and precision in the heart of Gold Country, Northern California. We are proud to say our products are Made in America.

Why choose James Cox & Sons?

Historic knowledge and the benefits of collaboration
Recently Cox & Sons has entered into collaboration with Cooper Technology. Established in 1990, Cooper Technology is a British company and one of the world leaders in the design and manufacture of high performance testing equipment for asphaltic and unbound materials used in highway construction. The Cox and Cooper collaboration has been formed to strengthen both the American and Global Asphalt, Concrete and Soil Testing supply chain. With over 50 years of combined experience our knowledge base is unsurpassed within our field of technical expertise. Both Cox and Cooper have reputations built on partnering academic institutions. Cox’s close links to UCB along with Coopers links to Nottingham University (NTEC) date back well over 20 years. Keith Cooper began working at the University of Nottingham back in the ‘60s. He worked under professors Pell and Brown. Keith, like Jim Cox was an inventor and innovator. With Steve Brown,Keith developed the Nottingham Asphalt Tester (NAT). The US apart, tests developed for the NAT are used and specified all over the world. Keith’s ideas are still being copied today, over 20 years later. Imitation is flattery, but design without experience and understanding produces poor copies. With Cooper Technology and James Cox & Sons you have over 50 years of experience in designing asphalt testing equipment. Cox and Cooper have a shared vision to design, develop and supply quality test equipment to a global market. We believe the collaboration will strengthen our current position and enhance the customer experience when dealing with the Cox and Cooper group of businesses. It is our joint intention to be a customer focused group. We listen and we care. The Cox and Cooper approach is to first establish customer requirements and then to offer best advice on the options available in order that customers can make informed decisions. We pride ourselves on working in partnership with customers rather than just “order taking”.


The NEW cDAC industry-leading control technology, based on over 50 years combined development experience. Precision control technology is essential to achieving accurate results. With over 50 years combined experience working closely within the civil engineering research community, Cox & Sons provides digital control technology that is unparalleled for its flexibility, scalability and simplicity of operation. No matter what your testing requirements, Cox & Sons offers the perfect control system to meet your every need. Our newly developed control system cDAC and universal software “DIMENSION” is the most advanced system available on the market today. The cDAC controller is a state-of-the-art, fully digital servo hydraulic controller that utilizes National InstrumentsTM RIO hardware and LabviewTM software. It is capable of running the most demanding static and dynamic tests. Fully digitalised with user defined arbitrary wave settings
as standard. No system offers as many input or output channels, using a fully automated input recognition system that pre-loads appropriate drivers and relevant calibration factors (TEDS –Transducer Electronic Data Sheet). True Universal Software with pre-loaded standard test database and a report writer function. The TDMS data output format provides far more information for the user and is fully compatible with Excel® and other Microsoft® software. NI Reconfigurable I/O (RIO) hardware and NI LabVIEWTM software provide the best platform to solve any demanding control and monitoring task. If you have a specific software requirement, the answer is YES our system can do it.


Our consultative approach ensures that your application is fully understood before an order is accepted, thus ensuring that the equipment ordered is fit for purpose and will deliver the expected results reliably, day after day and year after year. Our comprehensive design team covers various engineering disciplines; mechanical, electrical, electronic, pneumatic and hydraulic, coupled with a specialist software department, ensuring that everything gels together and functions as you would wish. Our products are tailored to suit your needs. Supplying the research, DOT’s and commercial sectors means innovation and invention. Innovation and invention is our provenance, work with us, you will enjoy the experience.


We recognize the need to speak your language. In support of this claim it is with great delight that Cox & Sons confirm the appointment of Dr. Geoffrey Rowe as a company specialist and consultant. Dr. Rowe is a member of the US Expert Task Group on asphalt binders and is a licensed Professional Engineer in New Jersey, Pennsylvania and Florida. Geoff Rowe teaches asphalt materials at various institutions and has pioneered a rheology course “Rheobit” which is presented at the Asphalt Institute, University of Nottingham and other institutions working in asphalt research. Geoff Rowe leads various research efforts on the performance of materials and the development of specifications. Geoff Rowe has over 50 publications, many on advanced materials and performance evaluation. Geoff Rowe’s fatigue work on asphalt mixtures has resulted in the development of the standard ASTM Beam Fatigue Standard Test Method – D 7460-08.
Geoff Rowe has over 30-years of experience in asphalt technology and regularly works with contractors, test labs and agencies on sites throughout the USA from his base in Pennsylvania. Geoff Rowe will work alongside Andrew Cooper in ensuring your every need is satisfied and no question is left unanswered when technical understanding is queried. Cox & Sons is much more than a manufacturer: the standard product portfolio presented by Cox & Sons has been carefully selected by Geoff Rowe and Andrew Cooper to best fit customer needs. These products have been designed and developed by an internal team
of degree educated engineers. The complete range of products is manufactured entirely in house by Cox and Cooper, offering the best of both American and British engineering qualities. We are proud to announce that American customers can procure from an American business knowing full well that they can depend on American support and the solid stamp of “American Quality.