The crash took place at about 7.15am on Sunday at the Frankfort Roundabout, near Camolin.
The man in his 30s was pronounced dead at the scene. His body has been brought to Waterford University Hospital where a post-mortem will be carried out.
The road had been closed for forensic examination but has since been reopened.
Gardaí are appealing to anyone who witnessed the collision to come forward, particularly road users with dash-cams who were travelling in the area at the time of the incident.