A pedestrian was struck by a Skoda Octavia as it entered the dual carriageway from Bone Island at around 9.25pm on December 26.
The casualty - a man in his 30s - was pronounced dead a short time later, police said.
A 29-year-old man from Skelmersdale was arrested at the scene on suspicion of drug driving and causing death by careless driving while under the influence of drink or drugs.
Detectives today (Monday, December 27) urged anyone who witnessed the incident or caught the collision on camera to come forward.
Sgt Martin Wilcock, of the Lancashire Police TacOps team, said: "This was a tragic incident and first and foremost our thoughts are with the family and friends of the man who died.
"We are now working extremely hard to piece together what happened and are asking anybody with information about this collision to get in touch.
"If you have any information at all, please let us know."
Anyone with information can contact police by calling 101, quoting log number 1076 of December 26.
You can also visit the Lancashire Police website by clicking HERE.
Alternatively, independent charity Crimestoppers can be contacted anonymously on 0800 555 111 or via https://crimestoppers-uk.org/.
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