A massive underground interchange beneath Sydney’s inner west will be opened to motorists within months, completing the final piece of the $17 billion WestConnex motorway and promising to relieve congestion on local roads and the Anzac Bridge.
A new 1.1-kilometre tunnel bypass of Victoria Road in Rozelle – linking the Iron Cove and Anzac bridges – will be free for vehicles, but motorists will be tolled when they pass through the rest of the Rozelle interchange and connect to other parts of WestConnex.
A worker walks through one of the interchange’s road tunnels which now has line markings. Credit: Jessica Hromas
Describing the complex project as an engineering marvel, NSW Roads Minister John Graham said the interchange was crucial to delivering travel time savings of up to 40 minutes for motorists using WestConnex.
“This is one crucial part of the puzzle. It’s one of the most complex construction projects ever completed in Sydney and possibly the country,” he said during a tour of the interchange.
Bordering the City West Link, a 10-hectare parkland above the underground spaghetti junction is starting to take shape and will largely be completed by the end of the year. Playgrounds, barbecues and pathways are being installed, and an oval and rectangular field on a site that was once the Rozelle rail yards will have grass put down within several months.
Australia’s most complex motorway project comprises 24 kilometres of tunnels beneath Rozelle and Lilyfield, about seven kilometres of which will mostly be used for ventilation.
Motorists and residents have had to endure major disruptions during the construction of the interchange over the last four years, which has involved 38 traffic changes on roads such as the City West Link. A further three will have to take place before the interchange opens.
Graham said the opening of the interchange by December would improve traffic flows on roads, but he cautioned that “not all the issues will be resolved” when the tunnels are completed.
“With these complex tunnels, motorists will need to take their time getting used to moving through,” he said. “It won’t be straightforward at first, but over time, as we’ve all gotten used to moving through these tunnels … this will make a real difference.”
The $3.9 billion interchange will connect the recently opened M4-M8 Link between St Peters and Haberfield, the City West Link, the Anzac Bridge, Iron Cove and, by 2028, the planned Western Harbour Tunnel. The latter will allow motorists to bypass the CBD, and avoid having to use the Anzac Bridge and Western Distributor to travel between the inner west and north shore.
A 10-hectare parkland is taking shape above the Rozelle interchange.Credit: Jessica Hromas
Graham said the government was “unapologetic about then shifting our priorities” to local roads once the final piece of the WestConnex project was completed this year.
Rozelle interchange project director Steven Keyser said it was now in the final testing and commissioning phase, which involved ensuring lights, signs, cameras and systems worked in accordance with the design.
“It’s lights, camera, action. We are very close to finishing the project,” he said.
All up, about 144,000 devices such as switches and signs need to be connected and tested. A high-tech control centre for WestConnex at St Peters will later oversee the interchange when it is in operation.
NSW Roads Minister John Graham at an entrance to one of the tunnels.Credit: Jessica Hromas
While the pandemic disrupted the project, one of the biggest challenges was removing about 7 million tonnes of spoil from the site, which required 250,000 truck trips. Much of the spoil was used to help build Western Sydney Airport at Badgerys Creek.
Keyser said the large number of motorway and ventilation tunnels within a small area also added to the project’s complexity. “We have two areas where three tunnels are stacked on top of each other. The deepest part is 55 metres [below the surface],” he said.
“What you don’t see behind all the panels is the network of cross passages that are fitted with electrical equipment. [It has] taken 19,000 people to do this job over a five-year period.”
Transport for NSW’s deputy secretary of infrastructure and place, Camilla Drover, said the 1.1-kilometre tunnel bypass of Victoria Road was projected to halve traffic on the latter and create opportunities to revitalise it.
Drover said the interchange would help relieve a traffic bottleneck on the Anzac Bridge and, together with the rest of WestConnex, deliver a 20-minute travel time saving for motorists driving between Parramatta and the Sydney CBD.
Like the other WestConnex tunnels, the Rozelle interchange will have a speed limit of 80km/h despite them being designed for 90km/h. The possibility of lifting the speed limit to 90km/h was aired during the NSW election campaign in March, prompting the state’s transport agency to assess the impact of any increase.
Distance-based tolls across the entire 33-kilometre WestConnex motorway are capped at $11.11 per journey for cars and motorcycles. The tolls for WestConnex are increased annually by the rate of inflation or 4 per cent, whichever is greater.
By the numbers
- Almost 17 kilometres of motorway tunnels and 7 kilometres of mostly ventilation passages.
- The tunnels required 1.74 million metres of cabling to be laid.
- Almost 7 million tonnes of earth excavated.
- Installation of 132 jet fans, 335 emergency phones and 7400 lights.
- Nine electricity substations built.
- The project has required 38 traffic changes on nearby roads since 2019.
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