The load limit is required to preserve the existing bridge with its original features.

The existing bridge was built in 1883 and is a State Heritage significant bridge.

A recent traffic survey identified there were only a few heavy vehicles per day using the bridge that exceeded 33 tonnes.

An alternative route for vehicles greater than 33 tonnes is via the Kamilaroi Highway (H29) from Boggabri to Gunnedah and then via the Gunnedah – Kelvin Road (in the Gunnedah and Narrabri shires).