The news confirms reports in The Scotsman last August which revealed the newly formed A9 Safety Group, which includes police and local authorities, was considering the plan.
The £122,000 scheme will remove more than 100,000 square metres of vegetation from a 41-mile section of the road between Perth and Dalnacardoch, just north of House of Bruar.
The work, which will continue until early next month, will involve lower speed limits over sections of the road, which carries up to 21,500 vehicles a day.
Much of the 113-mile section of the A9 between Perth and Inverness remains single carriageway, but upgrades since the 1970s have included long curves which were designed to provide a clear view of the road ahead to enable overtaking.
However, trees and bushes have grown at the sides of dozens of bends, preventing drivers from seeing oncoming traffic.
Experts say this has made overtaking more dangerous and increased motorists’ frustration, making them more likely to risk potentially fatal manoeuvres to pass slower vehicles.
Neil Greig, the Scotland-based policy and research director of the Institute of Advanced Motorists, said: “A clear view at junctions and for overtaking is an essential prerequisite of any safe road so we are very much in favour of this improvement work.
“It will have to be maintained, however, if the benefits are to be long-lasting.”
A9 Safety Group chair Stewart Leggett said: “This work is an important part of our safety plan for the A9. It will help drivers see more of the road ahead and this will give them a better understanding of what’s happening, improving safety as a result.
“We are focusing on engineering, education and enforcement as we look to improve conditions on the A9.
“A total of £137million has been spent on safety and maintenance on the route in the last five years, including work to improve junctions as well as overtaking opportunities, and over the next two years we expect to spend an additional £18m.”
Eddie Ross, north-west unit representative for Bear Scotland, which maintains the road, said: “This landscaping programme of roadside vegetation clearing will give further safety benefits to drivers by improving visibility.
“It will be particularly beneficial once the annual growing season starts.”