Commuters faced further traffic headaches this morning as dangerous road conditions doubled travel times.
The volume of traffic increased later in the morning as some employees waited until daybreak before beginning their journeys.
Aoife Carragher, from AA Roadwatch control centre, said they received reports of vehicles stuck on hills and a number of minor collisions and were anticipated more.
"We haven't seen any improvement in the roads," Ms Carragher said. "Traffic is slow and people are taking their time coming into work.
"It appears people are waiting until later, until it gets a bit brighter to travel into work."
There were a number of minor road traffic accidents on the N32 and Oscar Traynor Road in the early morning. Motorists abandoned their cars on Enniskerry Road to Lambs Cross which was causing problems for trucks to pass.
As much as 30-minute delays were experienced on the N3 Navan Road inbound from Clonee to the M50 and AA Roadwatch also warned motorists to be careful at Lucan, Chapelizod, Kylemore Road.
Conditions in Tallaght were particularly icy at the hospital and the bypass and on St Margaret's Road and Santry Avenue.
Gardai are advising motorists to avoid all higher ground and mountain roads as many are impassable. Local authority gritters were out on many main roads, but secondary roads remained treacherous.
Traffic volumes were light in the early morning as schools remained closed because of the weather. The Irish Primary Principals Network estimated that about 2,500 of the 3,200 primary schools in the country will be closed again today. That amounts to more than 75pc.
Dublin City Council has re-deployed 500 staff from waste management, drainage and parks departments to assist staff remove ice from roads.
Dublin Bus said that it was was operating a full service. However there are a number of areas where conditions where curtailments are in place.
Dublin Airport is open and operating normally today, but passengers are advised to consult airline websites or their airline directly before travelling to the airport.
And Irish Rail said services were at normal operating levels this morning, but the Docklands to Clonsilla services are now running between Clonsilla and Connolly. All Luas services are running as normal.