As Minister for Transport, Tourism and Sport, I have responsibility for overall policy in relation to roads. Matters relating to the management, including signage, of national roads are a matter for Transport Infrastructure Ireland under the Roads Acts 1993-2015 in conjunction with the relevant local authority. For regional and local roads it is a matter for each respective local authority. The Traffic Signs Manual, which my Department has issued, contains all information on which Warning Signs are necessary. There are no provisions of EU law as it stands that apply to this matter.
I would note that traffic signs generally follow international conventions, which of course should not be confused with EU or other law.
In relation to the operation of road traffic law enforcement, this is a matter for the Garda Síochána, as with law enforcement generally.