Flushing captured at Transmission Gully. (Photo in Stantec report)

from the NZ Herald

The Transmission Gully highway has been plagued by flawed chipseal and water seeping through the road’s surface before it has even opened, independent inspection reports reveal.

The chipseal defect has played a significant part in the road’s opening being pushed back once again; originally expected to open in April 2020, the road is now expected to open next year. Excessive flushing can mean roads are more slippery than they should otherwise be, compromising the safety of the road. It can also mean the road becomes sticky and car tyres end up pulling the bitumen further into the chipseal.

Extensive parts of the road have evidence of “flushing” — a phenomenon caused by bitumen seeping up through a layer of chipseal on top of it, according to two reports the NZ Herald has obtained under the Official Information Act.

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