Ireland has seen over the last decade or two a huge trunk road and motorway building program. The centrepiece of this investment was a network of radial motorways linking Dublin with other cities. Built under the Transport21 program, the bulk of the motorways had a closeout date of 2010, and were completed on time. For decades possessing 19th century road infrastructure, many of the Republic's trunk routes were catapulted into the 21st century in one go.

After 2008, however, Ireland's financial crisis greatly slowed the pace of this infrastructural boom and the remaining schemes in the plan no longer have completion dates. There is no longer an official road development plan and it has been clear for some time now that new road schemes around the country are being built in a fairly random manner, moving to construction as they get through planning, with no attempt being made to create end-to-end improvements of entire routes. This is in contrast to the building of the radial motorways, which were all end-to-end.

Below information can be found on existing and planned roads, including a list of all national roads currently under construction or about to start.



MOTORWAY MATRIX
Bolded roads exist or will soon; unbolded may potentially be created in the future. Further discussion on this.

 0123456789
0 M1M2M3M4 M6M7M8M9
1 M11     M17M18 
2M20M21 M22 M24M25  M28  
3          
4M40    M45    
5M50         

The M45 represents the future Leinster Outer Orbital and has been repeatedly moved to planning and then cancelled. No part of it exists yet and its numbering is uncertain.
In November 2021 it was once again cancelled and is unlikely to ever proceed.
Additionally, no sections of the N25 are motorway but the Waterford Bypass narrowly missed getting the designation in 2009 and it is possible that some may be created in future.
Therefore it has its own page.
Similarly the Cork Southern Ring Road was renumbered N40 in February 2012. It was formerly a part of the N25.
Although it is not a motorway, it is motorway standard and may be changed in future. It was therefore also given its own page.
It is planned to build an M21 Adare Bypass which will start at the M20, and in October 2017 it was confirmed that this will be motorway. This is expected to open by 2027.
Also by 2027, a new motorway, the M28, will be created, between Cork and Ringaskiddy port.

Click here for the full project tracker list, including information on all major previous and upcoming road openings.