Maddox spent much of his time towards the end of his career transitioning the army in Europe to a post-Cold War stance.

After retiring from the army, Maddox has worked as an independent consultant to industry and the government.

In October 2007, Maddox was part of a six-member panel appointed by Secretary of the Army Pete Geren that issued a report critical of the Pentagon's procedures for appointing and supervising contracting officers.

[4] He served as a member of the Department of the Army 120-day study, commissioned by Secretary of the Army John McHugh, to examine its acquisition organizations, policies, workforce and processes, including how it acquires and handles equipment.

Maddox received the Military Operations Research Society's Wanner Award for outstanding contributions to the progress of this advanced profession, the Institute for Operations Research and the Management Sciences' J. Steinhardt prize for lifetime contributions to the practical applications of OR techniques for the solution of military problems, and is a member of the Army Operations Research Society Hall of Fame.