Bank holiday traffic is expected to be heavier than usual today, with post-Christmas sales due to start this morning in all major cities.
Despite this, some travel companies are due to operate a Sunday service, and AA Roadwatch has advised motorists and shoppers to plan their journey in advance.
Dublin Bus will today resume a normal service on all routes, while most Nitelinks will operate at 12.30am and 2am. Both red and green Luas lines will operate as normal between 7am and 11.30pm, though the Dart network will run to a Sunday timetable. Clamping will be in effect in the city from noon today.
A spokesman for Bus Éireann said the company would run about 70 per cent of its services around the State. Most routes will follow a Sunday schedule, with some local alterations.
All Irish Ferries and Stena Line Services are expected to resume today, with sailings following a normal timetable.
Park-and-ride facilities are available today in Dublin, Cork and Galway. In Dublin, the facilities from Whitehall church and the Spawell will operate from 9am to 7pm, and it will cost €5 to park for 12 hours.
In Galway the scheme will operate every 15 minutes at the Ballybrit racecourse, while in Cork a park-and-ride is available at the Black Ash car park and runs every 15 minutes to the city centre.
A Dublin Traffic Control Centre spokeswoman said it was not expected that today's traffic would be as busy as a normal Tuesday, although it would be much heavier than a normal bank holiday because of the winter sales. "It wouldn't be like a normal rush-hour, as most people will still be off work, but it will be busy," she said.
"The shops will be busy more than us and we're hoping a lot of people come in on the buses."
She warned that car parks could fill by early afternoon and that city centre streets would be congested if that happened.
"Some of the sales in the large shops have a huge following. We're not expecting it to be like last week, [ but] it will definitely be busier than a normal bank holiday."
Many large clothes retailers begin their post-Christmas sales today.
The earliest opening time is 5am, when the Next store on Grafton Street, Dublin, will open its doors. A-Wear (nationwide), Brown Thomas (Dublin, Cork, Galway and Limerick), Clery's (Dublin) and Louis Copeland (Dublin and Galway) will open at 9am. The winter sale at Arnott's on Henry Street, Dublin, begins at 11.30am.
Met Éireann is forecasting another cold day today, with wintry showers possible on the east coast, although most of the country will be dry and sunny.