The country's airports, roads and rail networks are expected to be extremely busy over the course of the August bank holiday weekend, which gets under way today.
Motorists are being urged to take extra care over the weekend.
The Road Safety Authority says four people died and ten were injured in crashes this time last year.
Spokesperson Brian Farrell says it is one of the most dangerous times to be on the roads and appealed for the use of seat belts on every trip.
Meanwhile, more than 300,000 passengers are expected to travel through Dublin Airport between today and Monday 3 August.
The Dublin Airport Authority says over 2,000 flights will arrive and depart during this time, including 170 charter flights, which have been added to the normal schedule.
Iarnród Éireann says it expects up to 250,000 passengers to use its Intercity services over the weekend, with routes to Cork and Galway expected to be especially busy.
Meanwhile, the Connolly and Busáras stops on the Red Line of the LUAS in Dublin will be closed this weekend to facilitate the construction of the extension of the system to the Docklands.
Red Line services will operate between Abbey Street and Tallaght Saturday, Sunday and Bank Holiday Monday.
The Connolly and Busáras Luas stops will reopen at 5.30am on Tuesday.
The temporary closure is to facilitate the installation of overhead electricity cables for Luas Docklands
