Drink or drugs were responsible for a quarter of fatal collisions in Northern Ireland last year, police say, the highest level recorded for the last five years.
Some drivers stopped were so drunk they could barely talk, Assistant Chief Constable Barbara Gray said.
Police launched the annual winter drink-drive operation on Friday, which will feature random breath tests at vehicle checkpoints.
ACC Gray said: “During last year’s operation, we carried out over 12,600 preliminary breath tests at the roadside.
“At one end of the spectrum, we stopped drivers who were so drunk, they could barely talk, never mind drive.
“At the other, we detected some drivers who had gone out socialising and not intended to drive, but their circumstances changed and they decided to take a risk.”
Some who passed the test may think they had a lucky escape she said.
ACC Gray added: “Considering that statistics detailed in our report show that one in four (24.6%) of fatal collisions throughout all of 2016 in Northern Ireland were attributed to a principal cause related to ‘drink/drugs - driver/rider’, the highest level recorded in the last five years, I believe it is the other innocent road users, passengers and pedestrians who had the lucky escape.”
She urged people not to drink and drive this festive season, saying: “Just one drink can impair your decision making. Just one drink can cause a collision. Just one drink could kill.”
“Across the country, road policing officers, local and neighbourhood policing teams and our TSG colleagues will again be using legislation introduced last year to set up vehicle checkpoints and carrying out random breath tests as very visible, physical deterrent.”
The senior officer added: “We are determined to catch those people who take life-threatening, unacceptable, and simply stupid risks.”