Average speed cameras are being installed along a three-mile stretch of the Aberdeen Bypass.

The cameras will stay in place until work is complete on the A90 between Blackdog and Balmedie in mid-2017.

Transport Scotland said the cameras will make the road safer for construction workers and drivers.

Safety experts say average speed cameras installed on the A9 between Dunblane and Inverness have helped cut the number of serious crashes on the road, but campaigners have criticised the scheme.

A spokeswoman for the project said: "Since the beginning of the year, road users will have seen a significant increase in works across the project.

"The 50mph speed limit, which was introduced in January this year, will remain unchanged and the introduction of the cameras will help to ensure that this is observed.

"To enhance the safety of road workers on the A90 between Blackdog and Balmedie, who are now working in close proximity to road users in this area, additional safety measures are necessary."

Installation of the cameras is expected to begin on Friday.