A man in his 60s was killed when the car he was travelling as a passenger in left the road and collided with a barrier on March 14.
The female driver was taken to Tallaght Hospital where she remains in a critical condition, a Garda spokesperson said.
The crash happened on the south bound side of the M50 between the Ballymount Junction (Junction 10) and Tallaght Junction (Junction 11) in the early hours of March 14.
Gardai wish to renew their appeal for witnesses to this collision who may have been travelling South or North bound between Junction 10 and 11 at around 00:45am on the night in question to come forward.
Gardai are asking anyone with information to contact Terenure Garda Station on 01- 6666400, the Garda Confidential Telephone Line 1800 666 111 or any Garda Station.
A total of 39 people have been killed on Irish roads so far this year.