Durham's City-County Unified Development Ordinance (UDO) represents the first major overhaul of Durham's development regulations in more than 30 years and works in tandem with the newly adopted Comprehensive Plan to strengthen Durham's development regulations. It was adopted by the City Council and Board of Commissioners on December 5, 2005. The UDO became effective on January 1, 2006, replacing the previous Zoning and Subdivision Ordinances.