A vital stretch of the new Aberdeen Bypass will open this week.
Drivers can use the 28-mile section Craibstone to Stonehaven and Charleston from early on Wednesday morning.
Police will oversee a phased approach to open the junctions, starting at Craibstone.
Transport secretary Michael Matheson said: “This new section of road, which will make more than 85 per cent of the project open to traffic, will immediately make a tremendous difference to road users across the north east.
“It will provide thousands of drivers every day with a range of benefits, including improved journey time reliability, better local access and reduced congestion, while safety will also be enhanced.
“It will also improve air quality and reduce traffic volume in Aberdeen City, making pedestrian and cycle travel around Aberdeen easier, safer and a more enjoyable experience.”
Work on a bridge over the River Don will continue until later in December.
The development of the Aberdeen Western Peripheral Route (AWPR) is one of the biggest infrastructure projects in Scotland.
The cost was expected to be £745m when the project was given the go-ahead in 2009.
However, a Scottish Parliament committee heard last week it could now cost more than £1bn.
Discussions are ongoing between the contractors and Transport Scotland about who is liable for the extra costs.
The road was due to be completed in spring this year but bad weather, the collapse of one of the contractors, Carillion and problems with a bridge over the River Don has caused delays.
The completion date was then moved back until autumn.
Other sections of the road have already been open for several months.