Two state highway bridges in west Waikato will have weight restrictions introduced for heavy vehicles from 1 November 2021.

The Kopaki rail overbridge on State Highway 30 will be restricted to vehicles under 6 tonnes and the Mangaotama Stream bridge on State Highway 39 will be restricted to vehicles that are less than 50% of Class 1.

Waka Kotahi Waikato system manager Cara Lauder said that while weight restrictions can be inconvenient for trucks, the safety of all traffic “has to be the main priority”.

“We’d like to thank the freight industry for playing their part to ensure these bridges remain safe for light vehicles to use,” said Lauder.

The Mangaotama Stream bridge, two kilometres south of Ngahinapouri on SH39, needs a new deck and beams. A project to replace these was unsuccessfully tendered earlier this year and will be retendered once funding is reconfirmed.

The exact weight in tonnes of the Mangaotama restriction will vary between vehicles, depending on size and axle configuration.

The recommended detour for vehicles over 50% of Class 1 travelling between Otorohanga and north of Hamilton is State Highway 3 and State Highway 1 through Te Awamutu and Hamilton.

A detour is available at the bridge for local heavy traffic using Meadway Road, Hams Road, Forkert Road and Ngahinapouri Road. This detour is not advised for through traffic as it is narrow with single lane bridges.

The timber Kopaki rail overbridge, about 23km south of Te Kuiti on SH30, is currently restricted to 80% of Class 1. However a further restriction is required to ensure it can remain open to light traffic while the replacement bridge is under construction. The new bridge, which will be able to be used by all heavy traffic, will be complete in 2023.

Trucks travelling between Te Kuiti and Maniaiti/Benneydale will need to use the existing heavy traffic bypass of State Highway 4 and Kopaki Road.