The youth and two teenage girls were travelling in a car near the townland of Meelaghans on the Portarlington Road outside Tullamore, Co Offaly, at around 7.30pm yesterday when the crash happened.
The crash occurred on the same stretch of road where a crash claimed the lives of three Dublin brothers and their friend. The four men were killed when the car they were travelling in collided with a minibus at the very same spot on the road in August.
David (24), Darren (27) and Ryan Doyle (17), originally from Killinarden, along with Clondalkin man Lee Bryan (24) died on August 10 when their Honda Civic car collided with the minibus in which three occupants were injured.
Referring to last night's incident, Gardai say a second car was involved but appears to have left the scene.
It is understood that gardai have spoken to the teenage girls and are actively searching for the other driver. The teenager had to be cut from the wreckage of the VW Bora car he was driving after it left the road and reportedly hit a ditch before rebounding back into the road.
The two teenage girls were also hospitalised after the crash.
The R420 road remained sealed off this morning pending an examination by crash investigators, and diversions were in place.
All the victims were taken to Tullamore General Hospital.