Police are appealing for information after a collision involving a car and a pedestrian on the westbound carriageway of the B3400 at Newfound between Basingstoke and Oakley.
It happened at around 4.25am on Saturday, August 20.
A Vauxhall Insignia car, driven by a man in his 20s, was in collision with a pedestrian.
The pedestrian, a man in his 40s, sustained serious head injuries and is being treated at Southampton General hospital. The driver of the car was uninjured.
Anyone who may have witnessed the incident or has any information should contact the Roads Policing Unit at Whitchurch police station on 101 quoting Operation Seat. Alternatively call Crimestoppers anonymously on 0800 555 111.