Gardaí are trying to ascertain exactly how far the man drove on the wrong carriageway before his red Seat Ibiza ploughed into a Subaru Impreza driven by a man in his 20s.
The accident happened on the eastbound carriageway of the main Cork-Midleton road shortly before 11.30am.
It occurred at Harper’s Island, about 1km along the city side of the Carrigtwohill/Cobh Cross junction. Gardaí are appealing for anybody who saw the Seat Ibiza travelling the wrong way to call them.
The dead man — named locally as John O Driscoll, 82, from Innygreega, Midleton — may have driven the car all the way from his home to Harper’s Island.
However, it is also possible he became confused at either the Barryscourt or Carrigtwohill/Cobh Cross junctions and drove down the wrong slip road, leaving him facing into eastbound traffic.
Gardaí confirmed that just prior to the accident they received 999 calls from motorists who claimed they had to swerve to avoid a car travelling on the wrong side of the motorway.
It is understood that some people who came across the accident pulled the elderly man from the car fearing his vehicle was about to go on fire.
Mr O’Driscoll, who is the 94th fatality on Irish roads this year, was pronounced dead at the scene.
His body was removed to Cork University Hospital where an autopsy will be carried out. Five units of the Cork City Fire Brigade attended the accident along with one from Cobh and one from Midleton.
City fire brigade third officer Gerry Myers said they had to use cutting equipment to free the driver of the Subaru Impreza.
He was taken to CUH with suspected non-life threatening leg and chest injuries.
Major tailbacks occurred as gardaí had to close the motorway for several hours as forensic crash scene investigators carried out an examination of the area.
Diversions were put in place until 3.30pm.
Anybody with information about the incident should contact Cobh Garda Station on 021 4908530.
Meanwhile, as fire brigade crews were returning to the city from the crash they had to respond to calls that two young men had fallen into the River Lee near the Metropole Hotel.
Mr Myers said that his crews saved the two men, described as being in their 20s, and that they were taken by ambulance to Mercy University Hospital.