Mount Ousley Interchange capacity

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Mount Ousley Interchange capacity

Illawarra road network capacity
Mount Ousley, NSW
Smaller cities and regional centres
Efficient urban transport networks
Problem/Opportunity timeframe
Near term (0-5 years)
Proposed By
NSW Government
Date added to the IPL
26 February 2021
Mount Ousley Interchange capacity


The high volume of traffic on the Mount Ousley section of the M1 Princes Motorway is leading to significant congestion in peak periods.

The interchange also has a comparatively high crash rate. This is particularly due to an at-grade right turn across the M1, large speed differentials between light and heavy vehicles, and the current off-ramp configurations that cause significant weaving movements. These issues make journeys slower and less reliable for general traffic, and also reduce freight efficiency.

The M1 Princes Motorway is the primary transport link between southern Sydney and the Illawarra, serving Port Kembla, Wollongong and the NSW South Coast. It is an important connection for a range of domestic and export markets, including coal, steel, agricultural producers and consumer goods.

In 2019, approximately 54,000 vehicles used this section of the M1 Princes Motorway per day, around 16% of which were heavy vehicles.

The 2019 Australian Infrastructure Audit found that regional, rural and remote road networks are less safe than other road networks. There is an opportunity to focus investments and policies on these areas.

Proposed initiative

Potential options to address the initiative include:

  • adding or relocating on-ramps and off‑ramps
  • new interchange configurations
  • new service roads
  • adding heavy vehicle safety ramps.

These works could also consider public transport and active transport improvements to encourage mode shift.

Next steps

Proponent to identify initiatives and develop options (Stage 2 of Infrastructure Australia’s Assessment Framework).