A £30 million bypass of Enniskillen has been given the go-ahead.
The new road aims to cut congestion in the Co Fermanagh town and reduce journey times to counties Leitrim and Sligo.
Infrastructure Minister Nichola Mallon announced her plans to proceed with the scheme.
However, the Department for Infrastructure now needs to secure the £30m needed for the project.
Roads expert Wesley Johnston said delays to the A5 scheme between Derry and the border near Aughnacloy in Co Tyrone may "well mean there is funding around".
"It's obvious that there are a small number of bypasses that at the head of the queue," he said.
"Until there's money though there won't be anything happening on the ground."
Mr Johnston said the proposed Enniskillen bypass would bring benefits to the area.
"The A4 is the main route to Sligo, anywhere west of Enniskillen basically, and it goes right through Enniskillen town," he said.
"It is very congested... Getting traffic on to a bypass has the potential to open up the town centre too.
"There are people who would be reluctant to go into the town just because it's so difficult to get out of it."
The project will involve 2km of new single carriageway, including a 3m cycleway/ footpath, two new roundabouts and two river bridges.
The A509 Derrylin Road will also be improved between its junction with the new road and the A4 Sligo Road.
Ms Mallon said the bypass "is of significant importance to the town of Enniskillen and the surrounding area".
"It will provide a new transport link to the southern side of the town, improving the connection between the A4 Dublin Road and the A4 Sligo Road," she said.
"The bypass will also help to significantly alleviate traffic congestion in Enniskillen town centre, reducing delays, improving average journey times by approximately 50% and improving road safety."
Last month, Ms Mallon gave the green light to a £45 million Ballynahinch bypass.
The move means people travelling from Belfast to Newcastle will be able to bypass the Co Down town.
Sinn Féin MLA Jemma Dolan said the new scheme will reduce air pollution and congestion in Enniskillen.
"My constituency is one of the worst areas deprived of modern, decent roads," she said.
"In order to drive regional balance, we need to invest in the right infrastructure that helps us achieve that.
"I will continue to push for the delivery of this vital scheme."
Ulster Unionist MLA Rosemary Barton said former minister Danny Kennedy had announced the preferred route for the scheme almost 10 years ago.
"This will be a significant investment and benefit for the area when it is eventually constructed," she said.
"I trust the Department are looking beyond this part of the process and setting a timescale for when actual development on the ground can commence and a completion date."
