The R744 at Clonhaston will stay closed overnight to allow a forensic investigation to take place.
Local diversions are in place.
Gardaí in Enniscorthy are appealing to any person who may have information in relation to this incident to contact them.
Any person who was travelling on the R744 outside Enniscorthy this evening and through Clonhaston between 7.15pm and 7.40pm is asked to contact investigating Gardaí. Road users who may have camera (including dash cam) footage of this area are asked to make it available to Gardaí.
Anyone with any information is asked to contact Enniscorthy Garda Station on 053 924 2580, the Garda Confidential Line on 1800 666 111, or any Garda station.