A section of the Great Western Highway at Victoria Pass, including Mitchell's Causeway (also known as the Convict Bridge), remains closed following the detection of structural issues. The closure, which began around March 9-11, was initially estimated to last at least three months.
Authorities have confirmed this period will be extended.
Geotechnical assessments have revealed significant deterioration beneath the road, leading to an ongoing search for repair solutions involving national and international experts.
Closure Details and Cause
The Great Western Highway was fully closed at Victoria Pass, near Little Hartley in the Blue Mountains, after cracks and movement were detected in Mitchell's Causeway, a heritage structure built by convicts in the 1830s. Cracks were initially observed on the eastbound lanes on a Thursday, leading to a full closure of all lanes by early the following week.
Geotechnical studies conducted since the closure have identified a major geotechnical failure, significant bridge movement, and a risk of landslip.
These studies confirmed deterioration of the fill material beneath the road, along with voids and gaps within the causeway's structure. Proactive monitoring initiated in December had previously identified cracks and bulging. Engineers are actively drilling into the fill, installing instruments to monitor bore water pressure and ground movement, and utilizing 3D imaging for a comprehensive assessment.
Traffic Diversions and Impact
The closed section of the highway is a primary road link connecting Sydney to the Central West of New South Wales. It is used by an estimated 11,000 to 12,000 vehicles daily, including approximately 1,800 heavy vehicles.
Traffic is being diverted primarily through Lithgow to the Bells Line of Road and Chifley Road, and the Darling Causeway. Westbound traffic is detoured along the Darling Causeway at Mount Victoria to the Bells Line of Road and Chifley Road. Eastbound traffic is redirected via Lithgow to Chifley Road and either the Bells Line of Road or the Darling Causeway. Alternative routes such as the Golden Highway or the Hume Highway near Yass have also been suggested for those travelling to the Central West.
Increased Travel Times and Local Congestion
These diversions have resulted in increased travel times, ranging from approximately 25 minutes to two hours during peak periods. Lithgow has experienced increased traffic volumes, congestion, heightened noise levels, and challenges for residents accessing their driveways. The Bells Line of Road, a diversion route, is considered challenging for heavy vehicles, and a tow truck has been stationed there to assist.
Business Impacts
Local businesses, particularly in areas like Little Hartley, have reported significant financial impacts, with some noting substantial reductions in takings.
A survey of 300 Central West businesses indicated that over half experienced cost increases of up to 30 percent, citing factors such as reduced revenue, supply chain delays, increased fuel prices, and a decline in customers.
Businesses have requested financial support packages and promotional campaigns from the government.
Public Transport and Infrastructure Response
The New South Wales government has implemented several public transport adjustments to mitigate the impact:
- Amended school and regular bus services operated by Lithgow Buslines.
- Coaches operating NSW TrainLink services between Bathurst and Katoomba.
- Additional Sydney Train services between Bathurst and Mount Victoria.
In response to the increased traffic on detour routes, the NSW government has allocated $50 million for upgrades to the Darling Causeway, Chifley Road, and Main Street in Lithgow. This funding covers asphalt laying, road shoulder widening, and other general improvements, with work already commenced on some sections.
Investigation and Future Outlook
Initial assessments of the damage were projected to take approximately two weeks, with repairs anticipated to require at least two additional months under optimistic scenarios. However, NSW Roads Minister Jenny Aitchison confirmed that the closure is now expected to extend beyond the initial three-month estimate, and a new timetable will be established once a solution is identified.
To accelerate a resolution, the NSW government is convening a technical briefing on April 23, inviting experts from Australia and internationally to explore repair options. The procurement process for a solution will be fast-tracked.
Previous Plans and Reconsideration
Previous state and federal governments had funded initial phases of a 34km road widening project between Katoomba and Lithgow, which included an 11km twin-tunnel planned beneath Victoria Pass. This project's funding was ceased by the Perrottet government in 2022 and subsequently shelved by the Minns government in 2023 after a federal funding withdrawal. Remaining funds were reallocated.
A 2.4km dual-lane road was constructed at either end of the planned tunnel route, bypassing Little Hartley but still connecting to the single-lane Victoria Pass. The Roads Minister has stated that "nothing was off the table" regarding reconsideration of the tunnel plan.
Emergency services maintain accessibility to local hospitals and through the impacted area via alternative routes. A "whole of government response" is under development, though financial relief for affected parties has not yet been confirmed.