Over 4,700 roadside drug and alcohol tests took place during the St. Brigid's Day Bank Holiday Weekend.
Gardaí launched a major road safety operation from Thursday last week until this Tuesday.
Testing lead to 161 arrests for driving under the influence, and over 15% of those arrests happened between 6:00am and 2:00pm.
Eleven serious crashes happened in that period, resulting in two deaths and 12 people suffering serious or life-threatening injuries.
(pic Garda info)