There are reports of people stranded in their cars overnight in Dublin.
They're advised to stay inside their vehicles with the engine turned on for heat and wait for help.
Sean O'Neill from Transport Infrastructure Ireland says they're offering assistance but purely for safety reasons:
"Our network ops have come across people who are stranded. We've taken them to the nearest hotel and just left them there. That's all we can do because primarily we need to keep the network open and get their cars off the road."