The Coffs Harbour bypass project has reached several milestones in the last year, with major tunnelling, bridge construction and earthworks well underway.
The 14-kilometre Coffs Harbour bypass project is the final stage of the Pacific Highway upgrade program, one of the largest road infrastructure projects in Australia.
Connecting Sydney and Brisbane, the Pacific Highway is a major contributor to Australia’s economic activity. The existing highway through Coffs Harbour forms part of this freight corridor and carries between 30,000 and 35,000 vehicles per day. It’s also one of the last remaining sections of the highway upgrade that still has traffic lights.
Coffs Harbour bypass project director Greg Nash and his family have lived on the North Coast of New South Wales for over 20 years. He said they’ve seen firsthand the major changes and improvements in the Pacific Highway upgrade.
“Travel between places like Grafton and Brisbane has gotten much safer and that’s a great achievement, to see the benefits we’re actually making to the safety of the community.”
At the moment, road users are navigating 12 kilometres of low-speed arterial road through the CBD of Coffs Harbour. That’s 12 sets of traffic lights, a major roundabout and 26 at-grade intersections.
“This means the area experiences a motorist, cyclist and pedestrian casualty rate more than three times higher than expected of a road of this class,” Nash said.
“It also means increased travel time and inefficient on-road freight operation, loss of economic development opportunities and a decrease in the amenity of Coffs Harbour CBD.
“By providing the bypass for all the freight movements, predominantly, we’ll see some safer, more consistent travels through Coffs Harbour.”
The new bypass is also set to reduce travel times with improved freight transport efficiency and improved amenity for local communities. Additionally, it will provide a more reliable route with improved flood tolerance.
Key milestones
There were several firsts for the Coffs Harbour bypass project in 2024, including the commencement of tunnelling at Gatelys Road in January and beginning of excavation at Shephards Lane Tunnel. The microtunnel boring machine successfully completed the excavation of twin pipes beneath the Pacific Highway at Boambee and under the North Coast Rail embankment, a key step in the project’s tunnelling work.
Additionally, 2024 saw the installation of the first super-t girder at the bridge over Newports Creek, as well as several major approvals.
“Our Place Design and Landscape Plan and Operational Noise Report were approved in 2024, two fairly significant plans that help guide the project this year,” Nash said.
“We commenced one of the longest bridges, the 250 metre bridge over the North Coast Railway Line.
“As for earthworks, we’ve been tracking well. As of December 2024 about 80 per cent of earthworks are complete (2.65 of 3.3 million cubic metres) on the whole project.
“We also established our on-site asphalt batch plant and started paving at Korora Hill northbound on-ramp.”
At the end of October, crews completed a major traffic switch at Bruxner Park Road.
“We switched traffic over one of our newly constructed bridges and one of the central roundabouts, enabling us to open up the next phase of work,” Nash said.
“In the next 12 months, we’ll see more traffic switches, which enables opening up more of the existing highway to do work.
“We’ll also see the opening of the Luke Bowen pedestrian bridge and completion of hard rock drill and blast excavation at Roberts Hill and Shephards Lane Tunnels.
“This means we’ll see the tunnels actually finalised in terms of excavation, enabling us then to move on to the final part, which is pavements and full fit out of mechanical, electrical and any of the other polarised safety systems in the tunnels as well.”
Project complexities
The geology in Coffs Harbour presents unique challenges for tunnelling.
“The area is primarily made up of argillite rock, which is a very hard jointed rock mass,” Nash said.
“This is very different from Sydney, where tunnelling typically happens in sandstone, which is easier to drill through using tunnel boring machines.”
In Coffs Harbour, tunnel boring machines wouldn’t work as effectively, so the team relies on the traditional drill and blast method.
Despite the tough terrain, Nash emphasised that this hasn’t delayed progress.
“We’re now operating 24/7 in the tunnels, and tunnelling is ahead of schedule. It’s tracking really well.”
One of the project’s biggest hurdles is managing major earthworks in close proximity to urban areas and a high-rainfall environment.
“It’s 3.2 million cubic meters of earthworks right next to dense urban area,” Nash said.
“Then we have the added challenge of the high rainfall effects that come through Coffs Harbour because of the proximity of the Great Dividing Range to the coast. This has required some out-of-the-box thinking.”
To tackle this, the team has implemented cutting-edge erosion control measures.
“We’ve installed High Efficiency Sediment Basins (HESBs), which are EPA licensed and have five key features: automated dosing, coarse sediment bay, weir, settling basin, and outlet spillway,” Nash said.
“They provide continuous flow processing rather than the batch process of traditional basins. Treatment and discharge occur during a rainfall event, rather than after.
“This offers many advantages, the main being that a much greater volume of runoff can be treated for a given basin size, compared to traditional basins.”
With this solution in place, the team is effectively navigating the project’s challenges while maintaining high standards of environmental control.
Community engagement
“We’ve adopted a ‘no surprises’ approach to keep the community informed and minimise construction impacts,” Nash said.
The team shares updates via the project website, social media and emails.
“We’ve also got a bus that we take out to the community and actually talk to people about what’s happening.”
Nash said feedback is always welcomed from the community and stakeholders about the work and its impact.
“The surveys we’ve done have given us really good feedback, showing that the work we’re doing is really hitting the right note.
“I think a lot of people believed the project was never going to happen, but I think that’s starting to change.
“A lot of the project is hidden around the foothills, around the back of Coffs Harbour, and you can’t see it. That’s why the photo books and video flyovers of the project on our website are one of the best tools because the community can actually see what’s going on.”
Smart systems
The new bypass incorporates aspects of SMART motorway systems, and can be managed from St Helena’s Regional Traffic Operations Centre.
“The three tunnels need to be fully controlled 24/7 and they will be monitored through a regional traffic operation centre based up at Byron Bay,” Nash said.
Key intelligent transport systems include variable speed lane signs, variable and changeable message signs, overheight detectors, traffic signals, boom gates, CCTV and infra-red traffic loggers.
“These systems enable rapid, remote response in the case of an incident to close lanes, re-route traffic back through Coffs Harbour and prevent overheight vehicles from entering the tunnels,” Nash said.
Additionally, the tunnels are equipped with sensors to monitor smoke, heat and fires, ensuring a quick, effective emergency response.
These systems will ensure the bypass operates smoothly and safely once open.
“The Coffs bypass is on track to be open to traffic by the end of 2026. Once we open the bypass, we’ll return to finish work on the northern and southern tie-ins, which will take another 12 months.”
The project is set to be fully complete by the end of 2027.
