West Yorkshire Police have made nearly 400 arrests for drink or drug driving in December - an increase from arrests in December last year.
The force has published the figures as part of its December campaign, WYP The Cost, cracking down on drink and drug driving over the festive period.
In just 28 days, 396 drivers have been arrested for failing roadside breath tests for alcohol or roadside saliva specimen tests for cocaine or cannabis.
Last year, West Yorkshire Police made 284 arrests for drink driving and 92 arrests for drug driving throughout December.
There have been 20 more arrests this year than during the campaign in December 2018 - with three days still left in the month.
Chief Inspector Lisa Kirkland, head of West Yorkshire Police’s Roads Policing Unit, said: “Over the festive period, many of us will be out for meals, drinks and nights out with work colleagues, friends and family.
"What we are asking is for people to plan ahead and think not just about how they are going to get home on a night but also about their plans for the following morning.
“Every year, we catch people driving under the influence of drink or drugs not just in the evening but also the next day, dropping the children at school, driving to work, taking the car on a Christmas shopping trip.
“Christmas can be costly enough but think about what it would mean for your new year to be facing losing your licence, an unlimited fine and potentially time in prison.
“That really is the best case scenario as well. Drink or drugs has been listed as a contributory factor in 15 fatal collisions in West Yorkshire this year to date.
"This could be due to one or more drivers involved in the collision being under the influence but equally could be due to a pedestrian or cyclist being intoxicated.
"This festive season is a timely reminder for us all to look out for each other and for pedestrians as well to be mindful of their own safety.”