Planning is under way for a third lane in both directions along the Princes Motorway between Bulli Tops and Picton Road.
The $84 million project is a joint initiative of the state and federal government, with each contributing $42 million.
Federal minister for Major Projects Paul Fletcher said the work will be completed in two stages.
“Stage one of the project is due to start in 2017 and will provide an additional lane in each direction between Picton Road and Bellambi Creek,” Mr Fletcher said.
“Motorists will also see an improved road alignment at two locations, just south of Bellambi Creek and south of Cataract Creek.
“Planning for stage two, which would provide an additional lane in each direction between Bellambi Creek and Bulli Tops, is also underway.”
Stage one is expected to be completed in 2019 while a start date for stage two is yet to be determined.
Cataract Creek is at the base of the first downhill section after Picton Road heading north while Bellambi Creek is about a kilometre further on.
Environmental planning, finalising the concept and design and tendering for stage one will all be carried out before work on the first stage starts in 2017.
I think this will make a real difference to the driveability of that highway.Gareth Ward
Mr Fletcher said the extra lane northbound will link into the acceleration lane that starts at the Picton Road intersection and which was opened in 2014.
The upgrades will also include widening shoulders to three metres, removing tight bends through realignments and improving drainage.
Parliamentary Secretary for the Illawarra Gareth Ward said the upgrades will address the expected increase in freight on the road.
A 10 per cent increase in freight traffic is expected by 2025.
“Due to the tight turns and steep road, heavy vehicles are forced to travel slowly, which creates a marked difference in speed between light and heavy vehicles,” Mr Ward said.
He said it will also help with the issue that the two-lane motorway will have trouble handling traffic growth in its present form.
“It’s certainly getting to capacity but it’s also the fact that we want make a safer highway,” he said.
“I’m always champing at the bit for safer roads and better roads in our region.
“I think this will make a real difference to the driveability of that highway.”