The number of drug and drink-driving convictions in Wales rose by 18% in 2018 compared with the previous year, a report has found.
The Welsh Government report showed 3,882 people were found guilty of drink and drug-driving offences last year.
It added that while drug-driving tests had significantly increased, breath tests for drink driving fell by 11%.
Road safety charity Brake said the data showed both drink and drug driving were "still prevalent" on Welsh roads.
Ministry of Justice data included in the report showed the number of guilty verdicts in Wales for driving under the influence of a controlled drug above a specific limit rose by 95% in 2018, from 506 to 988 convictions.
However, the report said this rise did not necessarily reflect increases in drug driving due to significantly more drug testing being carried out by police.
The number of people found guilty of driving with alcohol in the blood above the prescribed limit rose by 3% from 2,285 to 2,353.
Despite a small rise in convictions in drink driving, the number of breath tests fell by 11% in the past year, with 36,975 conducted by Wales' four police forces in 2018.
It represents a continued fall in the number of tests in the past decade, 70% fewer than the 123,019 tests carried out in 2009.
Although the number of tests has dropped significantly, the number of positive or refused results was similar between 2017 and 2018, with 4,474 recorded in 2018, but this was the lowest total since 1992.
Meanwhile, speeding, seatbelt and mobile phone offences all fell between 2017 and 2018.
A spokesman for Brake said: "The findings from this report are a clear illustration that drink and drug driving are still prevalent on Welsh roads.
"Driving over the alcohol limit or under the influence of drugs is illegal and extremely dangerous behaviour with potentially devastating consequences, something which is particularly important to remind drivers of at this time of year."
The charity added: "We also need to see action by the new UK government to tackle this menace with a zero-tolerance approach to drink and drug driving.
The Department for Transport said: "Thousands of drivers have been prosecuted for drug-driving since new laws came into force in 2015, with over 9,000 in 2018 alone.
"Since 2010 there have been 14% fewer drink-drive accidents, but we are determined to reduce this number further - through our award-winning Think campaign, enforcement and tough penalties."
Drink-driving limits in England and Wales are currently set at 80mg of alcohol per 100ml of blood, but in Scotland, the limit was lowered to 50mg per 100ml.
Using test results from 21 motor vehicle drivers killed in road crashes in Wales, the report found 16 of these were below the legal limit of 80mg, but two of those killed had blood to alcohol levels of between 50mg and 80mg.
Three people who were killed in crashes in Wales had blood-alcohol levels of more than 200mg per 100ml of blood.