Temporary traffic lights are to be installed at the A9's Slochd Summit bringing short, single file traffic sections for a seven week period.
The Summit is one of the highest points on the trunk road at 401m (1,315ft) above sea level and is one of 12 sections of the A9 being upgraded from single to dual carriageway between Inverness and Perth. The work gets underway on Monday 13 February.
A Transport Scotland spokesperson said: "This ground investigation is needed to get vital information on the existing ground conditions in the vicinity of the A9 carriageway between Dalraddy and Slochd as we progress our plans to dual the road. This is the latest in a series of ground investigations taking place along the route.
“We apologise for any inconvenience these works will cause and would thank road users and local communities in advance for their patience over the next few weeks. The contractor will closely monitor the operation of the traffic management measures to ensure that delays are kept to a minimum.
“When planning their journeys, we’d encourage drivers to visit the Traffic Scotland website for the latest travel updates.”