The US 66 designation was recognized by the newly formed Arizona State Highway Department (sometimes abbreviated as ASHD) after the state highway system was reorganized on September 9, 1927. The reorganization entailed a transition from state-named highways to state- and U.S.-numbered highways. Arizona now had two principal cross-country U.S. Highways across the entire state: US 66 served the northern part of the state, while the southern half of Arizona heavily promoted and focused on US 80. Proponents of US 80 in Arizona had given their highway the nickname "The Main Street Through Arizona". At the same time, the newly formed U.S. Highway 66 Association dubbed US 66 the "Main Street of America", which may have been in response to the US 80 nickname. From 1927 onward, a friendly in-state competition existed between proponents of US 66 and US 80 within Arizona.