Orange City Council has completed a review of environmental factors for the project, which is now on public exhibition. 

Heavy vehicles would be required to detour around the work site, but access to all other traffic would be maintained for as long as possible, with full closures limited to high-risk activities like crane lifts. 

But once complete, the bridges would be able to carry B-doubles, cutting out the eight-kilometre diversion they currently have to use via Leewood and Bathurst Road.

When access across the bridge is closed, traffic would be diverted along Gardiner Road, Anson Street, Tynan Street and the Southern Feeder Road, adding 1.08 kilometres to a journey.

Orange mayor John Davis said letters would go out to all adjacent property owners, with signs, message boards and meetings with Orange Heath Service, Cadia Valley Operations, Orange Buslines and emergency services planned.

"This a major boost to transport infrastructure in Orange that will lead to much better access by heavy transport to these industrial areas,” he said.

“We’ll be asking for the patience of Orange residents when work gets under way, but we’ll be doing all we can to minimise the impact of the project.”

Quotes from prospective contractors will be assessed partly on their ability to minimise disruption to road users.

The 19-metre existing bridge at the East Fork will be kept to take northbound traffic, with a second 31-metre long bridge built on the eastern side for southbound traffic and a shared cycleway and footpath.

The second bridge will cost $2.5 million, funded by the state government’s Restart NSW Fixing Country Roads program and the federal government’s Bridges Renewal program, but the council with manage construction.

Work is expected to start in September.

To view the REF and have your say on the detours, visit http://yoursay.orange.nsw.gov.au/forestroadbridge.