Motorists can expect 30 weeks of delays as the latest phase of the massive A9 dualling scheme gets underway.
Single file traffic sections and temporary traffic signals will have to be introduced as work begins in earnest in Highland Perthshire.
A major milestone will be reached within a matter of days as the new £35m stretch of dualled road between Kincraig and Dalraddy opens after two years of work.
When complete, attention will shift to other sections of the A9 where dualling work is soon to begin after years of planning.
Ground investigations will begin on a 13.6 mile stretch between Pitlochry and Glen Garry.
That work is expected to last around 30 weeks and Transport Scotland has said the vast majority will be carried out away from the existing road.
However, some traffic management measures will be required to allow work beside the carriageway to be carried out safely.
Similar measures were in place earlier this year as specialist contractors carried out surveys of the rocky outcrops next to the A9 along parts of the route.
A Transport Scotland spokesman said: “This ground investigation is needed to get important information on the existing ground conditions in the vicinity of the A9 carriageway between Pitlochry and Glen Garry as we progress our plans to dual the road.
“This is the latest in a series of ground investigations taking place along the route.
“Traffic management measures will include alternate single file traffic sections controlled by temporary traffic signals.
“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 months.
“The contractor will closely monitor the operation of the traffic management measures to ensure that delays are kept to a minimum.
“While we do not expect major disruption to traffic, we would ask drivers to plan their journeys in advance using the Traffic Scotland website, twitter feed or Traffic Scotland radio.”
Cabinet Secretary for Economy, Jobs and Fair Work Keith Brown visited the Kincraig to Dalraddy dualling earlier this week ahead of its opening.
He said that 4.6 mile stretch alone would deliver a range of benefits to the public and the Scottish economy.
Next up will be construction of the Luncarty to Birnam section, where advance works, such as utility diversions (water/gas/telephone lines) – are to begin in late 2017/early 2018.
Transport Scotland is currently considering a shortlist of bidders for the main construction contract.