Work will start on the first stage of the $24.6 million duplication of Tuggeranong's Ashley Drive, on Wednesday, with the construction of a noise wall and pedestrian bridge.
The ACT government defended the unexpected costs, longer timeframe and smaller size of the duplication between Erindale Drive and Ellerston Avenue, when it was announced in last May's budget.
Transport and Municipal Services Minister Meegan Fitzharris said constructing a noise wall before construction was one of the "most common themes" to come out of community consultation in late 2014.
"A noise wall will be the first feature built to mitigate noise during construction as well as traffic noise when the upgraded road is operational," she said.
The ACT government has allocated $800,000 for Simeonov Civil Engineering to build the noise wall along the eastern side of the corridor between Statton Street and Isabella Drive.
It is expected to be completed by mid-2016.
The $1.1 million pedestrian bridge over Monks Creek linking Richardson and Isabella Plains also came from community feedback.
Tenders for its construction are still being evaluated and a contractor is expected to be appointed in coming weeks when an open tender process for the rest of the major duplication works will also be advertised.
"The upgrade will cater to all modes of transport, with north and southbound on-road cycle lanes, additional footpaths to link with existing off-road paths and the duplication of existing underpasses near Statton Street and Bugden Avenue," Ms Fitzharris said.