We’re more than halfway through the detailed design phase, and at the stage where engineers confirm that everything is working together as planned and where we identify any issues before finalising the design.
At the halfway point is where the design is more refined, and it confirms the big-picture approach before we dive further into the details.
Engineers have worked through many of the technical details, including:
We have been working closely with local iwi and the Waimakariri District Council throughout the detailed design process to ensure their aspirations and wider network plans are fully considered and integrated.
We expect to have final designs at the end of 2025.
There will be a grade separated interchange (overpass) at the intersection of SH1 and Williams Street, Pineacres. An off-ramp is included for traffic accessing Woodend via Main North Road and Kaiapoi via Williams Street.
The interchange will include south-facing ramps to access the motorway to head towards Christchurch.
The existing quarry lakes have grown in the time the designation for the new motorway has been in place. This means we need to reclaim part of the lakes to build a causeway for the road to cross the lake. To prepare for the new road, bulk fill material will be placed to form a solid base and an embankment for the new road. A new wetland area will be developed to the east of the road causeway.
Recognising the significant growth in the Pegasus, Ravenswood and Woodend communities since the original scheme design was developed, a motorway overpass with signalised on and off ramps will be included in the design where the Pegasus roundabout is now. The signalised intersections provide safer crossing facilities for pedestrians and cyclists between Ravenswood and Pegasus.
The interchange is also future proofed to allow space for a second bridge in the future if it is needed.
Overbridges at Woodend Beach Road and Gladstone Road maintain these local connections.
Woodend Beach Road will be realigned, avoiding the sharp bends.
There will be no motorway access to or from these roads.
Motorways are designed for high-speed, uninterrupted travel. Every access point (on-ramp or off-ramp) introduces potential conflict between entering, exiting, and through traffic. The more access points there are the greater the risk of crashes, as vehicles must slow down, merge, or cross lanes. With interrupted traffic flow it reduces the efficiency and safety of the motorway.
Local traffic is directed to use arterial or collector roads to reach motorway interchanges, rather than having frequent direct connections.
For the Belfast to Pegasus Motorway and Woodend Bypass, access to the local road network is provided only at key interchanges - Lineside Road, Williams Street, and Pegasus.
Detailed design has reached the 50 percent milestone. Explore the full layout of the project in the long plot design drawing below, which illustrates key features and alignment of the project at the halfway point.
Williams Street interchange [PDF, 48 MB]
Pegasus interchange [PDF, 43 MB]
As part of the detailed design phase and following data collected from the recent geotechnical investigations, planning is underway for work needed to strengthen the SH1 Kaiapoi River Bridge. This upgrade will improve its seismic performance and ensure the bridge can safely carry an additional southbound lane between the Lineside Road intersection and the Ohoka Road southbound slip lane. This lane will provide the capacity needed between the Lineside Road onramp and the Ohoka Road off-ramp.
The work is part of an early works package expected to begin in early 2026 and will involve strengthening the bridge columns by wrapping them with a special material called CFRP (Carbon Fibre Reinforced Polymer) along with strengthening of the bridge abutments.
The second piece of work included in the early works package is the reclamation of the quarry lakes within the road designation.
To prepare for the new road, bulk fill material will be placed to form a solid base and an embankment for the new road across the lake. Doing this early allows time for the fill to settle properly, helping ensure the main construction works can begin more smoothly and efficiently.
In early 2026 we will lodge applications for statutory approvals for the main construction package under the Fast-track Approvals Act (FTAA). The consent application documents will be made available on the Fast-track website:
fasttrack.govt.nz(external link)
