This article is about the motorway in the Republic of Ireland. For the motorway in Northern Ireland, see M2 (Northern Ireland). For the motorway in Great Britain, see M2.
A strip map of the M2.
The M2 originally opened as N2 Ashbourne bypass, with a dispensation for a 120 km/h speed limit. It became a motorway in the 2009 redesignations.
While the M2 itself is a relatively young motorway, studies into Co. Dublin's traffic flow right back in the 1960s proposed building a motorway along a very similar line. This road would have been D3M as far as Ashbourne, and then would have continued as a D2M to Drogheda, where it would allow traffic to continue towards Belfast.
This corridor was chosen as the preferred route precisely because it avoided the more densely populated T1 corridor, and would allow traffic to split more evenly into different routes into Dublin. As there was never much of a desire to build an inter-city motorway in Ireland, the original M2 was never progressed, until eventually the T1/N1 corridor had received so many upgrades that it became easier to link them all up.