7 6 . ▁The ▁section ▁of ▁the ▁M 2 5 ▁to ▁the ▁south ▁( Ch ert sey ▁to ▁Thor pe ) ▁began ▁in ▁July ▁ 1 9 7 8 ▁and ▁opened ▁on ▁ 9 ▁October ▁ 1 9 8 0 . ▁ ▁The ▁M 2 5 ▁north ▁of ▁here ▁to ▁the ▁j unction ▁with ▁the ▁M 4 ▁j unction ▁ 1 5 , ▁is ▁one ▁of ▁the ▁bus iest ▁roads ▁in ▁the ▁UK . ▁The ▁M 2 5 ▁reached ▁the ▁M 4 ▁from ▁the ▁M 3 ▁in ▁ 1 9 8 5 . ▁ ▁Const ruction ▁Const ruction ▁of ▁the ▁full ▁inter change ▁began ▁in ▁July ▁ 1 9 7 8 ▁and ▁it ▁opened ▁in ▁ 1 9 8 0 . ▁ ▁Str ucture ▁The ▁j unction ▁is ▁j unction ▁ 2 ▁of ▁the ▁M 3 , ▁and ▁j unction ▁ 1 2 ▁of ▁the ▁M 2 5 . ▁The ▁M 2 5 ▁north ▁of ▁the ▁j unction ▁is ▁ 5 ▁lan es , ▁and ▁south ▁of ▁the ▁j unction ▁it ▁is ▁ 4 ▁lan es ▁wide . ▁The ▁next ▁j unction ▁north ▁along ▁the ▁M 2 5 ▁is ▁the ▁Add l estone ▁Inter change , ▁and ▁south ▁along ▁the ▁M 2 5 ▁is ▁the ▁R unn ym ede ▁Inter change . ▁The ▁design ▁is ▁a ▁tur bine ▁inter change . ▁The ▁B 3 8 9 ▁( west ) ▁and ▁B 3 8 8 ▁( east ) ▁pass ▁east - west ▁close ▁to ▁the ▁north ▁of ▁the ▁inter change . ▁Ch ert sey