 In South Australia , a decade @-@ long program to seal the highway began in the mid @-@ 1960s . The first section to be completed was the 462 @-@ kilometre ( 287 mi ) route between Port Augusta and Ceduna , in December 1967 . In October 1972 the Ceduna to Penong seal was completed , and the final link to be sealed , between Penong and the state border , was completed with a ceremony held on 29 September 1976 near <unk> Tank , South Australia . Between Yalata and the state border , the highway was realigned and deviated considerably from the original unsealed route . In deciding the new alignment for the South Australian section of the highway between Yalata and the state border , long , straight , flat sections were purposely avoided to prevent driver boredom and consequent fatigue , as well as sun @-@ glare and glare from oncoming headlights . The new alignment also took into consideration the potential tourism opportunities provided along the coast of the Great Australian Bight . The older highway route runs from Border Village to the Nullarbor Homestead , approximately 15 to 20 kilometres ( 9 @.@ 3 to 12 @.@ 4 mi ) away from the coast . The previous route from the Nullarbor Homestead to <unk> Motel also travelled further inland than the new alignment , past Ivy Tank Motel and Yalata Roadhouse . 
