99 people tested positive for drug driving in County Cork in the first four months of the year.
The Irish Examiner reports the figure is higher than the number of people caught drink driving during the same period for the first time ever.
Chief Superintendent Con Cadogan says he isn't surprised by the increase in drug driving and says the offence could soon make up two-thirds of all driving-while-intoxicated arrests.
Legislation to tackle drug driving was introduced two years ago.
