A 37-year-old driver died at the scene following a collision involving two cars on the A6 near Steinfort in the direction of Belgium at around 2am on Wednesday, according to police.
The second driver tested positive for alcohol but sustained "no serious injuries", police said.
The forensic and accident investigation teams are on site to determine the cause of the collision, while the public prosecutor has requested an autopsy.
The motorway was closed towards Arlon for a prolonged period with traffic being diverted via the Steinfort exit, however it has since been reopened.
Police issued an appeal for witnesses on Wednesday morning, stating that another car is believed to have overtaken the two vehicles involved shortly before the accident.
The driver of that vehicle, as well as any other witnesses with information, are asked to contact the Capellen police station on +352 244 30 1000 or by email at police.CAPELLENSTEINFORT@police.etat.lu.
