The M1 extension to Raymond Terrace will remove up 25,000 vehicles a day from the Tarro Bridge, the state government has revealed.
The 36 per cent reduction is expected to occur when the $1.7billion project opens in 2028.
Until then, Transport for NSW will work to maintain the 60-year-old piece of critical road infrastructure in a safe condition.
Much of the deterioration that has occurred in the past two decades is the result of the significant increase in heavy vehicle traffic passing over the bridge.
Documents obtained under Government Information (Public Access) show UGLRL engaged engineering consultancy BG&E to conduct inspections on the bridge between April and October.
The inspections highlighted concerns relating to the deterioration of parts of the bridge's structure. As a result, BG&E advised the bridge did not comply with Australian Standard 5100.
It prompted UGLRL to recommend that the bridge be closed.
"For as long as UGLRL remains responsible for Tarro Bridge under the Operations and Maintenance Deed, UGLRL's position will remain that the bridge should be closed to public traffic until such time as it is able to be rated in accordance with AS5100," it advised on October 17.
A team of Transport engineers, accompanied by technical experts from the Australian Rail Track Corporation (ARTC) inspected the bridge on October 18 and 19.
Transport concluded that, apart from general material degradation, the likelihood of failure was "extremely unlikely" based on traffic controls that were in place.
Maitland MP and Minister for Regional Transport and Roads minister Jenny Aitchison said on Thursday that the bridge remained under a routine inspection program and was performing as expected.
"As Minister for Regional Transport and Roads, safety is always my top priority and Transport for NSW has consistently applied a precautionary approach to the management of the safety of Tarro Bridge," she said.
"Meanwhile, construction on the M1 Pacific Motorway extension to Raymond Terrace is on track and due to open in 2028 and this extension will remove up to 25,000 vehicles a day from existing local roads including Tarro Bridge and end long-time traffic bottlenecks in the area."
Newcastle Herald readers were divided about whether the government should have revealed that it had been advised to close the bridge.
"Some of you who are old enough might remember the Granville train crash with many fatalities. The incident changed the legislation around rail bridge integrity and the responsibilities of track owners to maintain bridges to standard. If there were reports of structural problems why weren't TfNSW prosecuted?," a Maitland resident wrote on Facebook.
However, another said Transport had handled the situation responsibly.
"(Revealing the information) It have just had the public panicking over things they don't understand and caused even greater traffic woes. With the benefit of hindsight, it would appear they made the right call," they wrote.
