The Road Safety Authority is advising motorists to take care after an updated Orange weather warning was issued from Met Éireann.
The warning forecasts fog across the east, northeast and midlands again this evening until tomorrow morning.
Foggy in northern half of the country.Cold with frost tonight except for W & SW coasts where it will be cloudy with some rain.Lows -2 to +3C— Met Éireann (@MetEireann) November 26, 2014
Motorists are advised to switch on dipped headlights and fog lamps, reduce speed, and keep a safe distance from the vehicle in front.
If the fog closes in, reduce your speed further and take your time getting to your destination.
Open your window a little so you can listen out for other road users, particularly at junctions.
Vulnerable road users should avoid cycling or walking in fog unless it is a necessity.