The 7.5-mile (12km) Balmedie to Tipperty section of the new Aberdeen bypass will fully open to traffic on Wednesday, it has been announced.
The £745m, 28-mile (45km) route was given the green light by Scottish ministers in 2009, but was delayed by legal action.
The first main part - between Parkhill and Blackdog - opened in June.
Michael Matheson, cabinet secretary for transport and infrastructure, said the opening was "very welcome news".
He said: "Every day tens of thousands of drivers will now begin to reap the benefits of this section of new road."