A 41-year-old man died after he was knocked down at Coyne’s Cross in Ashford at around 1.30am.
A 21-year-old man was later arrested under road traffic legislation and brought to Gorey Garda Station but was subsequently released.
Gardaí have asked for anyone who was on the N11, travelling south between 12.30am and 1.45am, to contact them.
They say they want to speak to people who may have seen the man walking, or who witnessed the collision.
All diversions have been lifted, but motorists are warned that conditions remain icy in the area.