A teenage motorcyclist was killed and his passenger seriously injured when his bike crashed into a lamppost in the north of Dublin.
Coolock gardai launched an investigation into the accident in Clarehall. No other vehicle was involved.
The accident happened at 4.20pm yesterday.
"An 18-year-old male motorcyclist was fatally injured when his motorcycle collided with a lamppost," said a garda statement.
"He was pronounced dead at the scene and his body removed to Beaumont Hospital.
"A 23-year-old male pillion passenger was seriously injured and has been taken to the Mater Misericordiae University Hospital."
The road was closed and diversions put in place while garda forensic collision investigators examined the area.
Gardai have appealed for witnesses to contact Coolock Garda Station on 01 666 4200.
Alternatively, they can call the garda confidential line on 1800 666 111 or any garda station.
Dublin Fire Brigade said two fire tenders, an ambulance from Swords and UCD emergency care attended the scene at the Clare Hall roundabout.
Two pedestrians were also killed in separate road accidents in Limerick and Cork.
A 40-year-old man died when he was hit by a car in Kileely Road in Limerick city on Sunday night.
In the second accident, a man was hit by a lorry while walking in the Bridge Street area of Cork city at 11am yesterday. He died at the scene.