A blanket of dense fog caused commuter chaos as it swept across the country.
Motorists were warned to take extra care as the M1, M3 and M50 motorways were among the main roads worse affected by the blanket of fog.
Bus services were also delayed as traffic came to a standstill in parts of the capital.
AA Roadwatch urged caution on roads in several counties across the country, including Dublin city centre, Louth, Meath, Wexford, Wicklow, Leitrim, Monaghan and Donegal.
In Dunboyne, at least three cars have hit the roundabout on Maynooth Road. No one was injured in the multi-vehicle car crash.
An accident was also reported on the Malahide Road near Griffith Avenue.
Meanwhile the Main Street Castlebellingham remains closed while gardai probe a fatal car crash, which is believed to have been caused by dense fog.
“We are advising motorists to slow down, take extra care and give themselves more time to get to their destination,” AA Roadwatch said.
“Use your fog lights in the affected areas but be sure to switch them off afterwards.”
Met Eireann said it’s misty this morning with dense fog patches and poor visibility.
“This will slowly clear to give a dry day with sunny spells developing,” it said.
“Fog patches again will be dense in places tonight and Saturday morning with poor visibility."
Dublin Bus said while it very foggy this morning, particularly in the city centre, it did not have any major problems.