Seven motorists were arrested after gardai carried out a series of checkpoints testing for drivers under the influence of drugs and alcohol on bank holiday Monday.
A massive Mandatory Intoxicant Test took place in Dublin this morning, when 230 drivers were tested for alcohol and 20 for drugs on the M50 at Junction 16, Cherrywood.
Gardai arrested three motorists who tested positive for alcohol and one for drugs.
One of the arrested parties was already disqualified from driving and an outstanding warrant was out for their arrest.
A garda spokesman tweeted: "Motorway Mandatory Intoxicant Testing checkpoint, M50 at Cherrywood this morning. 231 drivers tested for alcohol, 20 for drugs.
"Four arrests in total. 3 for positive alcohol tests and 1 for drugs, including a disqualified driver re outstanding arrest warrant. # ArriveAlive"
Gardai in Dublin arrest two for drug driving after 'super' MIT checkpoint
An unaccompanied learner driver was stopped by a routine patrol in Ballinrobe, Co. Mayo and tested positive for cocaine, they were arrested and brought to Castlebar Garda Station and the vehicle was seized.
In a separate incident in Mayo a driver failed an MIT checkpoint after testing positive for cannabis.
During a follow up search of the vehicle a quantity of cannabis was recovered and the driver was arrested.
At an MIT checkpoint near Letterkenny, Co Donegal a driver tested positive for cocaine and cannabis, while several motorists were detected speeding in the same area.
