[5] Cellular Business Systems, Inc. (CBSI) was the first company to provide billing services to the U.S. cell phone industry.

He was a founder of the organization that became the Cellular Telecommunications and Internet Association (CTIA) and was the President of the Automotive Multimedia Interface Collaboration (AMI‑C).

Shields was Convenor of the international working group developing standards for vehicle-vehicle and vehicle-infrastructure communications (ISO/TC204/WG16).

Mr. Shields is a member of the National Space-Based Positioning, Navigation and Timing Advisory Board, a Presidential Commission (United States).

He received the 1998 SAE‑Delco Electronics Intelligent Transportation Systems Award for distinguished service to the ITS industry, and was named an SAE Fellow in 2007.