As Minister for Transport, Tourism & Sport, I have overall responsibility for roads policy in Ireland. However, under the Roads Acts 1993-2015, the planning, design and implementation of individual road projects on national roads is a matter for Transport Infrastructure Ireland in conjunction with the relevant local authority and is a matter for the relevant local authority in the case of regional and local roads.
Should the request, therefore, relate to the location of a sign on a national road, then it would be a matter for Transport Infrastructure Ireland (TII) in conjunction with the relevant local authority. However, should the request relate to the location of a sign on a regional or local road, then it is a matter for the local authority itself, which in this case would be South Dublin County Council.
In either case, the Traffic Signs Manual (TSM) stipulates the traffic signs to be used on Irish roads, their layout and symbols, the circumstances in which each sign should be used and the rules for positioning them. The TSM constitutes a Ministerial Direction to road authorities under section 95(16) of the Road Traffic Act 1961, and is available from my Department's website.