The number of cars using the M50 has dropped by 30% during the coronavirus pandemic.
Last Sunday was the quietest day of the year so far with 60,000 vehicles recorded on the Dublin motorway.
Similar reductions have been recorded on the Jack Lynch Tunnel in Cork, the Killarney bypass in Kerry, and on the M7 near Ballysimon in Limerick.
Transport Infrastructure Ireland (TII) expects a further drop when this week's figures are available.
Sean O'Neill from TII says its clear people are playing their part.
"We all have to abide by the requirement to not travel if we do not have to," said Mr O'Neill.
"The logical conclusion here is to get through this emergency and everyone needs to stay at home as required.
"So we will see a significant drop-off in traffic over the coming weeks and again it's all part of our collective effort to accommodate the needs of the entire country.
"We need to make sure that the personnel who need to get to hospitals and who need to do their jobs to save lives can do that."