A stretch of road affected by landslips has closed for stabilisation works, expected to take a year.
Dorset Council previously said there was a risk of a fatality on the C13 at Dinah’s Hollow, near Shaftesbury, Dorset unless tree felling and stabilisation works went ahead.
The road will be closed between Boundary Road and the B3081, with access for residents and emergency services between Boundary Lane and West Lane.
The C13 is a key north-south route for Dorset. Previous landslips have completely blocked the road and concrete safety barriers are in place to mitigate any further collapse.
During the closure, a diversion route will be in place on the A350 but HGVs travelling southbound will be directed along the A30 to Shaftesbury then on to Stalbridge and the A357 to re-join the A350 south of Steepleton Bends.
Other measures, including one-way systems and temporary 20mph speed limits, will be in place to support the flow of traffic in villages affected by the diversions.
Jon Andrews, cabinet member for place services at Dorset Council, said: “This is a vital safety project to protect everyone who uses the C13 and to make sure this route remains resilient for the future.
“We recognise these works will affect travel, so we have reviewed all options and developed a comprehensive package of traffic management measures.
