1983 Tennessee state highway renumbering

The Tennessee Department of Highways, predecessor to the Tennessee Department of Transportation (TDOT), was founded in 1915, and gradually assumed control of major routes throughout the state. The first 78 state routes were designated in 1923,[1] and additional routes were added over the course of the succeeding decades. By the time of the 1983 takeover, the state route system consisted of approximately 175 numbered routes, in addition to many special suffixed routes. Suffixes and special designations used included "-A" for alternate, "-Byp" for bypass, "-Bus" for business routes, "-Conn" and "-Spur" for connector and spur routes, and "-Temp" for temporary routes. The Tennessee state route shield consisted of a white inverted triangle with the number in large black print and the letters "Tenn" below in smaller capital letters.[2]

As traffic increased on roadways throughout the state, many counties increasingly struggled to appropriate the funding to maintain their major roads, many of which connected to Interstate Highways.[3] In addition, a 1983 study conducted by TDOT found that a number of important roads were partially maintained by both the state and local governments.[4]

In May 1983, Tennessee Governor Lamar Alexander signed legislation which allowed for the state to assume control of 3,300 miles (5,300 km) of city and county maintained roads, and made an additional 11,500 miles (18,500 km) of rural roads eligible for state aid.[5] TDOT took control of these roads on July 1, 1983, and incorporated them into the state route system.[6][7] In addition, as part of this process, the state renumbered most of their suffixed and special routes with by replacing them with extensions or rerouting of existing routes or entirely new designations altogether.[4] State routes were also divided into primary and secondary highways, with new primary shields unveiled to the public in November 1983;[8] secondary routes retained the inverted triangle shields, with the "Tenn" removed. Primary designations were given to highway sections that are part of the Federal-aid primary highway system, and secondary routes, commonly called county routes, are part of the Federal-aid secondary highway system. The sign changes were implemented in 1984 at a cost of $1.3 million (equivalent to $2.91 million in 2021[9]).[8]