Gardai are investigating whether a fatal two-vehicle motorway collision was caused when another vehicle did a U-turn at a toll plaza and drove the wrong way along the southbound carriageway.
An elderly motorist was killed and a young man was seriously injured in the collision in north Cork, which happened shortly after 11am yesterday.
The tragedy brings the number of people killed on Irish roads this year to 187.
That represents a 15.5pc increase on the numbers who died in 2015.
Total collision numbers were also up this year, by almost 14pc.
Yesterday's crash happened a short distance from junction 16 of the M8 between the north Cork villages of Rathcormac and Watergrasshill.
A garda source said they are investigating whether the collision was caused by a vehicle that approached the Watergrasshill toll plaza on the southbound carriageway.
It then appeared to do a U-turn and drove the wrong way against oncoming traffic.
The collision involved two vehicles, a Mitsubishi Pajero and a van.
The driver of the Mitsubishi, Tom Joe O'Riordan (84), from Castlelyons, Co Cork, suffered critical injuries and died at the scene before he could be transferred to Cork University Hospital. He is understood to have been a farmer.
The van driver, a man aged in his 20s, suffered multiple injuries.
He was taken to hospital by ambulance and remains in a serious but stable condition.
If it is confirmed that a vehicle was driving in the wrong direction on a carriageway, it will be the second time such an incident has been responsible for a fatality on the M8 in north Cork in recent years.
A vehicle being driven the wrong way down the north-bound carriageway outside Fermoy resulted in the death of a young man three years ago.