The incident occurred at around 1.50pm on Wednesday at the Sarsfield Rd Roundabout in Wilton.
The driver, a man in his 50s, was taken to Cork University Hospital, where he was later pronounced dead.
An autopsy will take place in due course.
The scene was preserved for a technical examination and the road has since reopened.
Any road users who may have camera footage (including dash-cam) and were travelling in the area between 1pm and 2pm on Wednesday December 3, are asked to make this footage available to investigating gardaí.
Anyone with information is asked to contact Togher Garda Station on (021) 4947120, the Garda Confidential Line on 1800 666 111, or any Garda station.