Princes Highway remains one of the worst roads in the state, according to motorists.
Almost 8000 road users voted the Princes Highway the fourth-worst road in NSW or the ACT as part of the NRMA's annual Seeing Red on Roads campaign.
It also topped the list for local roads, followed by King Georges Road, Heathcote Road, the M5 and Forest Road.
NRMA local director Marisa Mastroianni said the results showed it was time to extend the F6.
"It's not coincidental that the most common complaint relates to congestion and other commuter issues, including traffic-light phasing and lane width," she said.
"There are major road and public transport projects scheduled for Sydney, all of which will help alleviate congestion.
"It's time to add the F6 extension and improve the public transport network if we want to deal with local congestion.
"The Princes Highway is clearly past its use-by-date. In addition to commuters coming north from the Illawarra, there's the mass of local peak-hours traffic.
"Two of the reddest roads in NSW and the ACT either pass through or pour into this area."
The most flagged roads in southern Sydney were:
- Princes Highway
- King Georges Road
- Heathcote Road
- M5
- Forest Road
