The victim was transported to Southside Hospital in Bay Shore where his injuries were determined to be consistent with being struck by a vehicle.
The man, who was in serious condition, was also suffering from hypothermia.
Police say it is unclear how long he was in the roadway.
Investigators are looking for assistance in identifying the victim who is described as a Hispanic man, approximately 30-years-old, approximately 5 feet tall and between 140-150 pounds.
He was wearing a black shirt, dark jacket, and blue jeans.
Anyone with information regarding the victim's identity or about the incident is asked to call anonymously to Crime Stoppers at 1-800-220-TIPS or the Third Squad at 631-854-8352.
All calls will be kept confidential.