Roscommon Roads policing unit detected a driver travelling at 144 kilometres an hour in an 80 kilometre zone on the Roscommon/Longford border at Rooskey yesterday during National Slowdown Day.
Gardai say court proceedings are to follow as a result of the detection.
More than a thousand drivers were found to be going above the speed limit during the 24 hour exercise which began in the early hours of yesterday morning.
Two drivers were caught going more than 200 kilometres per hour – one was detected doing 201 kilometres per hour on the M8 at Cashel in county Tipperary, while another was caught on the M50.
In total, just over 126,000 motorists were checked for speeding.
The aim of the day was to advise drivers to watch their speed and save lives.
So far this year 57 people have lost their lives on Irish roads.