The A5 starts at a crossroads in Derry where the Craigavon Bridge meets the A2.

A section of the route near Dublin forms the M2 motorway . This estimate was revised upwards to £650–850 million in November 2008, £844 in August 2009 and then reached £1.049 billion in October 2016.The Republic of Ireland was meant to contribute €460 million of the cost. The A5 Western Transport Corridor is one of five key transport corridors identified in the Regional Transportation Strategy for Northern Ireland.

However, in May 2011 the Republic's In 2011 a set of four public inquiries into the A5WTC was held.
"Ms Begley said more unnecessary delays "will ultimately result in commuters' lives being put at risk". This work is likely to include the publication of an addendum to the existing Environmental Statement followed by a six-week public consultation process. Road closure required to facilitate planing, binder course, ironwork and surface course. The project is called the A5 Western Transport Corridor,It was suggested that the new road would reduce journey times from Derry and Northern Donegal to Dublin by 20 minutes. The Inspector’s report is scheduled for completion in September 2020. "Progress on this vital piece of infrastructure has been delayed over the past decade by repeated legal challenges by an unrepresentative minority group," she said.

Their report was submitted to the Minister for Regional Development in March 2012 and published in 31 July.A campaign umbrella group called the Alternative A5 Alliance (AA5A) had been founded in 2010 to oppose the A5WTC. What this means in practice is that, in terms of process, the Department moves back to a point in time just before its decision to proceed with the scheme in November 2017 and, as a result, the Direction and Vesting Orders for the scheme are no longer in force. This first section of the A5WTC scheme to be constructed is approximately 15 kilometres in length with works expected to start early 2018.►Copies of the Notice of Intention to Proceed, Planning Appeals Commission (PAC) report and the Department’s Statement can be viewed online at the links below.►The final versions of the RIAA’s, together with a Habitats Regulations Assessment Summary Report that set out an assessment of those impacts and all other documents relating to the project that include the Direction / Vesting Order maps can be viewed at: ►A legal challenge to the Department’s Decision was submitted by the Alternative A5 Alliance (AA5A) on 22 December 2017.Having given careful consideration to recent High Court decisions as well as the provisions of the recently enacted NI (Executive Formation and Exercise of Functions) Act 2018, the Department decided that it was not in the public interest to continue defending the legal challenge brought about by the AA5A. Supporters of the project are hoping, with a new power-sharing executive in place, it can finally move forward.However, opposition to the project still remains and further delays may be likely. Órfhlaith Begley hopes the public inquiry will allow the project to "proceed with haste" In September 2012 the AA5A began legal proceedings against the A5WTC. "The inquiry, at the Strule Arts Centre in Omagh, will discuss the possibility of road work affecting air quality, cultural heritage, landscape and visual effects. Its improvement represents a significant link in plans to improve strategic links between the urban centres of Londonderry, Strabane, Omagh and Aughnacloy and improves connections to the North West. The judge found against the Department on one count and ruled that an appropriate assessment under the Habitats Directive should have been carried out in respect of the River Foyle and River Finn Special Areas of Conservation. Information on the Roads Service proposals to upgrade the A5 Western Transport Corridor in Northern Ireland between the City of Derry and Aughnacloy. Consequently at a Court hearing on the 15 November 2018, the Department invited the Court to quash the above mentioned Orders and this took effect from Friday 16 November 2018.

I think it is safe to assume that the overall A5 dualling scheme is now costing over £1bn, making it the single most expensive road project ever undertaken in Northern Ireland, beating even the building of the M1 and M2 in the 1960s/early 1970s. It's Northern Ireland's biggest ever road project - but will it get back on track after a new public inquiry?