A section of the A46 between Cold Ashton and Batheaston will be closed overnight for six-and-a-half weeks from Tuesday so new safety signs can be installed.
The six static "bends ahead" warning signs are being put in around the Hartley Bends in response to the number of crashes in the areas.
There will also be two electronic vehicle activated signs which will display a bend symbol and warn drivers to slow down.
The Highways Agency is also taking the opportunity to resurface the road.
Project Sponsor Mark Arberry said: "We are very pleased to be able to introduce these signs which should significantly help to improve safety by giving drivers additional warning that they are approaching the bends.
"The work to being carried out at night between 8pm and 6am when traffic flows are at their lowest and to make the most of the closure we are also undertaking resurfacing work at the same time; this will reduce the need for further closures for resurfacing in the future, so reducing disruption to road users.
"We advise all drivers using this section of the A46 to allow slightly longer to complete their journeys."
Councillor Martin Veal (Con, Bathavon North) said: "At long last we have welcome action from the Highways Agency on the Hartley Bends.
"These remedial measures to improve safety will hopefully begin to save lives on the A46.
"It has taken me many years to make them take action on this KSI black spot, however, the excessive speed of traffic still remains the elephant on the road and apparently a step too far.
"Nevertheless I am grateful what has been proposed is now being actioned."
A 4.3 mile section in both directions of the A46 between Cold Ashton roundabout and the A4, London Road will be closed during the works and a clearly signed diversion route will be in place.
The scheme will be completed by Wednesday, April 30.
Northbound traffic will be diverted along the A4 towards Chippenham, then the A350 and on to the A420 before rejoining the A46 at Cold Ashton Roundabout.
Southbound traffic will follow the same route in the opposite direction.
