 When it opened in 1978, the tunnel was the southern end of State Highway 2.Alterations at the Ngauranga SH1/SH2 interchange in 1984 connected SH1 to the motorway; although SH1 continued off the Aotea Quay offramp until 1996.In 1996 Transit extended the SH1 status to the entire route from the end of the Wellington Urban Motorway to Wellington International Airport.