Councillors resolved to pass a motion which approved council's $900,000 commitment to improve road and pedestrian access on the Old Hume Highway at Balaclava and Willow Vale.

Council's transport planning engineer Frank Iacono said the project came about because of a proposal from John Holland Rail to replace and re-align a bridge over the Picton to Mittagong loop line on Railway Terrace.

"They have approached us incidentally to talk about replacing the bridge over the Mittagong to Picton loop line and we were able to convince them to put it in a new location," Mr Iacono said.

"The bridge is going to be substantially bigger than the existing bridge in that it is going to be substantially wider, as the existing bridge is around seven metres wide in total and the new bridge accommodating shared paths and wider pavement will end up being about 29 metres wide."

Negotiations with the Roads and Maritime Service (RMS) have resulted in full support of the project and its proposed results.

The project will include improvements for pedestrian access including a shared path on both sides of the railway over bridge, a proposed pathway between traffic signals at Renwick Drive and the bridge and safe pedestrian and cycleway access across the Old Hume Highway between Willow Vale and Balaclava.

Bus bays on each side of the highway and traffic signals to help Willow Vale and Balaclava traffic entering and leaving the Old Hume Highway will also be included in the project.

"Because of the four way intersection, signalisation is important to be undertaken in conjunction with the road works," Mr Iacono said.

"This will provide ease of access to Willow Vale and Balaclava communities and also provide safe pedestrian crossings."

Mr Iacona said these improvements would help the increased traffic in these areas flow better.

As the Old Hume Highway is a main road it has more than 20,000 cars a day using it and at the current rate of growth, the number is expected to rise to about 30,000 cars a day before 2031.