The roadworks to Birdseye Highway from Cleve to the Lincoln Highway have been completed.
The $2.5 million upgrade was announced by the state government in late 2018 after advocacy from the council to cater better to heavy truck movements.
Cleve mayor Phil Cameron said he was "pretty proud of those blokes".
"The contractors and everyone involved has done a pretty good job because they got it done in a timely fashion and it's definitely made a huge difference," he said.
Cleve-Kimba road works are also expected to begin in August to reinstate the speed limit to 110km/h after shoulder sealing is completed.
Member for Flinders Peter Treloar said a contract for the works had been awarded to Downer EDI.
"The works on the Cleve Road will consist of 67 kilometres of shoulder sealing between Kimba and Cleve, and also include new line marking, replacement of guide posts and the installation of audio tactile line marking," he said.