The man, from Chorley, was struck by a Volkswagen Polo in Pall Mall shortly before 1am on Sunday morning (July 28).
Police said the man is believed to have been standing in the middle of the road when the collision occurred.
The 29-year-old has suffered serious head injuries and is currently in a serious but stable condition at Royal Preston Hospital.
No one has been arrested, but police are appealing for any eyewitnesses to the incident to come forward.
Sgt Oliver Jones from Lancashire’s Tactical Operations said: "I appreciate this happened in the early hours of the morning when not many people will have been out and about but if you think you witnessed this collision or have any information about it, please come forward.
"It happened at shortly before 1am on Pall Mall when a Volkswagen Polo collided with a man believed to have been stood in the road.
"The 29-year-old man from Chorley suffered serious head injuries and is currently in a serious but stable condition at Royal Preston Hospital."
If you witnessed the incident, you can call 101 quoting incident reference 0092 of Sunday, July 28.