Drivers will face three weeks of roadworks on the A9 from the weekend.
The A9 will be reduced to one lane in both directions at the dual carriageway stretch at Killiecrankie, as well as a reduced speed limit of 50mph.
The restriction is to allow repairs to the retaining walls at the side of the road.
The work starts on Monday, but BEAR Scotland warned motorists to expect delays on Sunday night as staff prepare the road.
Eddie Ross, BEAR Scotland’s north west representative, said: “These works are necessary to ensure the structural integrity of the retaining walls supporting the A9 at Killiecrankie.
“The lane closures are essential to make sure that everyone is kept safe during the maintenance work.
“Our teams will look to complete the works as quickly and safely as possible. We encourage motorists to plan their journeys in advance and check Traffic Scotland for real-time journey information.”
Roadworks are expected to be in place for three weeks.
The announcement comes amid more delays on the A9 north of Perth as preparations begin for the next stage of the £3 billion project to dual the trunk road between the Fair City and Inverness.
Engineers are about halfway through the eight-week programme, between Luncarty and Pass of Birnam, which has resulted in a 30mph limit during weekdays.
The dualling project has caused controversy in Perthshire, particularly in Killiecrankie, where a campaign group is fighting to stop the new road being built over part of a historic battlefield.
More than 180 people have objected to a Scottish Government bid to gain the land needed for the Killiecrankie to Glen Garry phase.
Transport bosses are using compulsory purchase powers to snap up more than 240 roadside sites.
A public inquiry could be called to settle any disputes if landowners refuse to sell.
Transport Scotland is in negotiations with 182 objectors along the 13-mile stretch but said the opposition is unlikely to cause any delays to the dualling project, which is still on target for completion in 2025.
Another hearing took place in June 2015 after objections to the Luncarty to Birnam phase.
An agreement was eventually struck with main objector Network Rail.