The passing of the
Main Roads Act of 1924 through the
Parliament of New South Wales provided for the declaration of Main Roads, roads partially funded by the State government through the
Main Roads Board (later
Transport for NSW).
Barrier Highway was declared (as Main Road No. 8) on 8 August 1928, from the intersection with North-Western Highway (today
Mitchell Highway) in Nyngan, via Cobar, Willcannia, and Broken Hill, to the border with South Australia; to provide for additional declarations of State Highways and Trunk Roads, this was amended to State Highway 8 in April 1929. The highway was fully
sealed in October 1972. The passing of the
Roads Act of 1993 through the
Parliament of New South Wales, updated road classifications and the way they could be declared within New South Wales. Under this act, Barrier Highway today retains its declaration as Highway 8, from Nyngan to the state border with South Australia. Barrier Highway was signed as National Route 32 across its entire length in 1955. With both states' conversion to their newer alphanumeric systems in 1998 and 2013, its former route number was updated to A32 for the highway within South Australia in 1998, and within New South Wales in 2013. ==Major intersections==