A man was killed after his motorbike crashed into a roundabout on the N81 heading towards the M50 on Sunday morning.
The incident happened at about 2.15am and the man, who was in his mid-20s, was pronounced dead at the scene.
The road was closed for a time for a technical examination but has since reopened.
Gardaí are appealing for witnesses and are asking anyone with information, particularly those who were travelling on the N81 early on Sunday morning, to contact them at Tallaght Garda station on 01 - 6666000, The Garda Confidential Line 1800 666111 or any Garda station.