NZTA Southland contract manager Justin Reid said the work on the outside lane of the road did not satisfy NZTA’s required standards. It had failed within days of its completion — leaving the road in worse condition than before the work started.
Based on its design, the chip seal for the road should have lasted seven years, he said.
But performance also depended on multiple factors, including seal layers, traffic volume, stresses and seal type.
Work at the intersection was completed on May 1, which included road markings. It cost $11,421.
High water tables, tidal fluctuations and a high volume of heavy vehicles had caused the road seal to fail.
The inside lane had more extensive work carried out to cater for heavy traffic exiting the heavy vehicle bypass link at a cost of $449,523.
The failed resurfacing on the outside lane, which was predominantly used by lighter vehicles, was meant to provide a better waterproofing layer to the road’s base.
"This can be compared to putting a new coat of paint on a weatherboard house ... to stop them from rotting."
The costs of the remedial work on the defective strip would be completed once weather was warmer at the expense of the installing contractor, he said.
About 10% of the national highway network were repaired or rehabilitated each year between spring and early autumn.
NZTA monitored the nation’s state highways with data that provided a comprehensive picture of road conditions.
Invercargill City Council declined to comment on the state of the Invercargill city road or its repair as the State Highway came under the jurisdiction of the national road network.
- By Toni McDonald
