Ferren served as lead designer, engineer, and producer of the 50-state, 16-month tour of the Bill of Rights, which celebrated the document's bicentennial. For the tour, he designed and built the Bill of Rights Secure Transit Vehicle, which transported the fragile parchment document, as well as a 15,000-square-foot travelling exhibit equipped with state-of-the-art lighting, A/V, security, and safety systems. He was the chief designer for the award-winning Columbus Center Hall of Exploration, a science discovery center, located at Baltimore's Inner Harbor in 1997.