A group of 45 Traveller caravans moved last night from the end of the M1 motorway in Dundalk, Co Louth after individual notices were served on their occupants ordering them to move.
There are more than 150 men, women and children living in the caravans. They arrived in the area last Friday and were parked in the central reservation where the motorway ends and construction of the next section starts.
The Travellers are believed to be from Rathkeale in Co Limerick and told gardaí they were in the area to attend a wedding.
However there were grave concerns about the safety of motorists using the road and for Traveller children. The road carries over 25,000 vehicles per day between Dublin and Belfast.
Gardaí, a dog warden, a litter warden and senior council officials visited the site yesterday.
After initial negotiations with the Travellers they were asked to move from the area by 3.30 p.m. They had not left by 4.30 p.m. and gardaí then served an occupant of each caravan with a legal order to move on.
Garda Supt Pat Magee of Dundalk confirmed the orders were issued under the Miscellaneous Housing Provisions Act 2002 which gives gardaí powers to move people on in such situations.
A time limit was not specified but it was believed that if they had not moved by this morning, gardaí and possibly the county council would consider either prosecutions or an injunction.
He confirmed there had been a traffic accident involving at least two cars close to the site and said that overnight last night they would be "paying a lot of attention here as I have concerns about safety, not just of motorists but also for the many children".
It emerged yesterday that the land the Travellers camped on belongs to the county council and it could seek a High Court injunction forcing them to move.
The dog warden and litter warden also visited the site and the council was considering using powers it has under the Control of Dogs Act and Waste Management Act. Earlier a spokesman for the council said it would review its position this morning.