More people died on Irish roads in the last 12 months than in 2018, with 148 people losing their lives in 137 fatal crashes in 2019.
That represents a 4% increase since 2018, when 142 people died in crashes.
2018 remains the safest year on Irish roads since records began.
These provisional figures have been published by the Road Safety Authority (RSA) following an analysis of collision reports by An Garda Síochána.
The figures show some positive news as the numbers of pedestrian and passenger deaths have both declined in 2019.
However, 25 more drivers lost their lives in the past year than in 2018.
The RSA has described this 45% rise as a "worrying increase".
RSA Chairperson Liz O'Donnell has said that the overall year-on-year increase is "deeply saddening", but that the figures should "spur us and our road safety partners on in a renewed effort" to improve road safety.
The Government's eight-year strategy to reduce the number of road deaths to 124 will finish at the end of 2020.
However, the RSA says that despite the 2019 increase, this target can still be achieved by saving two more lives a month every month in 2020.
The provisional figures for 2019 also showed that more than half of all fatalities happened on Thursdays, Fridays and Sundays, with Sunday being the most dangerous day.
September and December proved to be the worst months, with 20 and 16 deaths in those months respectively.
New figures released by gardaí today show that in the last year, 9,658 drivers were arrested on suspicion of driving under the influence of drink or drugs.
The number of detections in relation to drug driving doubled in 2019, with more than 1,200 arrests.
Garda statistics also show that more than 133,000 motorists were caught speeding in 2019, while 28,000 were found holding a mobile phone while driving. Another 11,000 were detected driving without a seatbelt.
An Garda Síochána says that roads policing is a priority for 2020 and that 180 extra gardaí have been allocated to the area in the early part of this year.
A new mobile app that will "revolutionise" roads policing will also be rolled out.
This will mean there will be more than 4,000 devices in the hands of frontline gardaí by the end of the year.