▁Autor oute ▁de ▁Bret agne ▁( ), ▁is ▁a ▁French ▁autor oute ▁located ▁in ▁Y vel ines , ▁near ▁Paris . ▁It ▁branches ▁off ▁from ▁A 1 3 ▁( also ▁known ▁as ▁the ▁Motor way ▁of ▁Norm andy ) ▁at ▁an ▁exchange ▁known ▁as ▁the ▁Tri angle ▁de ▁Roc qu enc ourt ▁located ▁in ▁the ▁town ▁of ▁B ail ly ▁and ▁mer ges ▁with ▁R N 1 2 ▁and ▁R N 1 0 ▁at ▁Bo is - d ' Ar cy . ▁Its ▁total ▁length ▁is ▁ 8 . 5   km ▁( 5 . 3   mi ). ▁Access ▁is ▁free . ▁ ▁It ▁has ▁not ▁been ▁length ened ▁since ▁its ▁construction , ▁which ▁makes ▁it ▁the ▁oldest ▁French ▁motor way ▁to ▁have ▁remained ▁on ▁its ▁original ▁route . ▁ ▁Its ▁history ▁started ▁in ▁ 1 9 3 4 ▁with ▁the ▁publication ▁of ▁Plan ▁Pro st , ▁which ▁en vis aged ▁a ▁network , ▁already ▁dense , ▁of ▁motor ways ▁in ▁Î le - de - France . ▁ ▁The ▁A 1 2 ▁was ▁then ▁known ▁as ▁the ▁" A utor oute ▁de ▁Bret agne ", ▁which ▁is ▁a ▁reference ▁to ▁its ▁proxim ity ▁to ▁the ▁nearby ▁R N 1 2 ▁route ▁which ▁extends ▁to ▁Brit t any . ▁Its ▁construction ▁began ▁in ▁ 1 9 3 6 ▁with ▁the ▁first ▁def or est ation ▁on ▁the ▁site ▁of ▁the ▁Tri angle ▁de ▁Roc qu enc ourt . ▁Work ▁ceased ▁at ▁the ▁out break ▁of ▁war ▁in ▁ 1 9 3 9