The drivers had been fined and given two penalty points for speeding but it emerged yesterday that the speed limit in question had been increased and they were not breaking the law.
They were all fined in error after Louth County Council increased the speed limit from 80kph to 100 kph on a section of the former Dublin to Belfast road but failed to change the speed limit signs.
The motorists were caught by a fixed speed camera at the bottom of Tullyesker Hill at Killineer, north of Drogheda or by the Gatso speed camera van.
The gardaí confirmed there had been an “administrative error” on their part and the fines would be returned and penalty points removed.
Around 380 motorists could benefit from the mix-up, which saw them paying €80 and getting two penalty points for apparently breaking the speed limit.
The bye-law came into effect on April 28 and €24,000 has been taken in fines to date. Where appropriate, it will be repaid.
The garda press office said gardaí would be going through the records and anyone who was under the 100kph will be refunded. The Department of Transport will be asked to cancel the penalty points.
However, a spokesman added that anyone who was doing more than 100kph will not be refunded.
The decision to increase the speed limit was made by the council. Its senior executive officer, Patrick Donnelly, says statutory procedures were followed. The change was advertised in the local press and it wrote as required to the local garda chief superintendent.
Mr Donnelly admitted it should have changed the signs so that motorists were alerted to the new limit.