For the first time, last year Finnish police found the same proportion of drivers who were impaired by illegal drugs and other medications as there were drivers under the influence of alcohol.
Slightly more than 12,000 intoxicated drivers were caught by police in Finland last year.
While the number of drunk drivers has steadily declined for a number of years, the number of people driving under the influence of illegal drugs and other substances has increased significantly, police added.
Most people found driving under the influence of substances other than alcohol were aged between 25-34 years old.
"For that age group, the number of people who are driving having had a drink, meaning those who had a blood alcohol content below 0.5 milligrammes, has also increased," said Petri Varjos, a forensic specialist from the National Bureau of Investigation.
The data shows stark regional differences. Helsinki Police Department reported drugs and other substances featuring twice as often as alcohol in cases of intoxicated drivers.
In contrast, Eastern Finland Police Department found that alcohol was still by far the most common intoxicant.