Quite a number of people on Irish roads have UK issued driving licenses. Either because they learned to drive in the UK, are immigrants from our next door island, or they are from Northern Ireland. The law which gives these licenses validity is EU law, and unless there is a specific agreement on this point, all UK licenses holders lose the legal right to drive in Ireland on 30 March 2019.
Nonsense - you might say. Aren't Americans allowed to drive here? Well, yes. Because of the United Nations convention on road traffic. The UK is not a member of it.
They are now in a mad rush to join. But whether they will manage to join and implement all the red tape required by Brexit day is uncertain.
Anyone with a UK license here has the next 12 months to get it converted to an Irish license. Might be a good idea.