A severe weather warning was issued today as temperatures were forecast to plummet to minus five degrees.
Motorists were bracing themselves for treacherous conditions over the weekend as the cold snap left many routes icy and slippery, especially on high ground.
Met Eireann said showers of sleet and snow will fall in many areas, with the northern half of country and western counties most at risk.
Freezing fog can also be expected.
Transport Minister Noel Dempsey urged all motorists, cyclists and pedestrians to take extra precautions when travelling during the cold snap.
“Visibility is reduced for everyone in snow and foggy conditions,” he said.
“Remember other roads users may not expect you, so slow down, be alert and always expect the unexpected when driving, cycling or walking.”
Nicola Hudson, of AA Roadwatch, revealed flurries of snowfall have already affected visibility in the Dublin suburbs of Lucan, Mulhuddart and Blanchardstown, with more than 120 drivers calling its breakdown service by mid morning.
“With very low temperatures and frost forecast, it is likely that road conditions will be very dangerous,” she said.
“Motorists should take particular care when driving overnight and in the early hours of the morning.
“Road temperatures are often far lower than the air temperature and often drivers may not realise the roads are still icy.”
Ms Hudson warned that on winter mornings roads often re-freeze around 8am and cause car crashes.
Drivers were advised to allow extra time for all journeys and watch out for black ice on all roads, particularly in sheltered areas.
Key areas to be cautious include the Conor Pass, Co Kerry, Barnsmore Gap in Co Donegal, Sally Gap and Wicklow Gap and Dublin’s M50.
Elsewhere, Age Action urged members of the public to make an extra effort to keep in contact with elderly neighbours in the coming days.
Spokesman Eamon Timmins said sub-zero temperatures, sleet and snow forecast is particularly challenging for older people living alone.
“The cold can kill,” said Mr Timmins.
“It is important that everyone plays their part to ensure that those who are frail or house-bound remain safe and well over this period.
“We are reminding people to call in on their older neighbours to ensure they have enough fuel and basics such as milk and bread. Older people can also play their part by keeping in telephone contact with each other and with their family and neighbours.”