Commissioner Cass joined the NHDOT in 1986 and has over 35 years of state service with the NHDOT. Prior to serving as Assistant NHDOT Commissioner, he held a number of supervisory and management positions at the Department including, Final Design Supervisor, Preliminary Design Section Head, Chief Project Manager, Assistant Director of Project Development, and Director of Project Development. Bill was one of the Project Managers for the largest project the NHDOT has ever undertaken - the 20-mile, 800-million-dollar reconstruction and widening of Interstate I-93 from Salem to Manchester and was involved with the project throughout its development and construction. He is also actively involved on committees for the American Association of State Highway and Transportation Officials (AASHTO), and the Northeast Association of State Transportation Officials (NASTO).

Bill has a Bachelor of Science degree in Civil Engineering from the University of New Hampshire, and lives with his wife Colleen, in Laconia.