Work to repair the slow vehicle lane on State Highway 1 at the Picton Elevation to stop future ground movement and build resilience is largely complete with all three lanes open. A temporary speed limit of 70km/h will be in place until chipseal can be applied when the weather is warmer.
Following the most recent movement of the slow vehicle lane on State Highway 1 at the Picton Elevation in early 2023, investigation, monitoring and design work was undertaken to determine the best way to repair this stretch of the state highway.
Investigation and monitoring revealed the groundwater flow was under pressure and had pushed through the state highway. This caused upward pressure just below the surface of the slow vehicle lane, cracking the road’s surface
In early January 2024 horizontal drains were installed to slowly drain the pressurised water under the highway. Additional culverts were then installed, with associated inlet and outlet protection, along with under road cut off drains to improve slope stability by controlling groundwater pressures through subsurface drainage. Following this work the team was able to make repairs to the road surface of all three lanes.
On 8 June all three lanes reopened. To ensure the safety of all road users a temporary speed limit of 70km/h will remain in place until a layer of chipseal can be applied when the weather is warmer.
Due to the complexity of this site, we will continue to monitor this section of State Highway 1.
Drainage works as part of this project have been funded from the Transport Resilience Fund announced in 2023. Road repair works have been funded from the Emergency Works Fund.
Close| Stage | Action | Status |
| Stage 1 | Preparation for directional drilling. This includes:
|
Complete |
| Stage 2 | Installation of directionally drilled drains. The excavator will be onsite to reach into the creek and directionally drill pipes back under the road. |
Complete |
| Stage 3 | Installation of new culverts. Installation of new sumps and drainage channels on the eastern side of the state highway. Installation of new outlets and bank protection on the western side of the state highway. Slumped pavement repair in the western slow vehicle lane. |
Complete |
| Stage 4 | Road reopens to three lanes under a 70km/h temporary speed limit | Complete |
| Stage 5 | Chipseal applied to three lanes and 100km/h speed limit reinstated | September/October 2024 |
