Police are appealing to anyone who was driving on the A24 near Southwater, south of Horsham, at 2pm on Saturday (July 13) and may have seen a pedestrian in the road.
Emergency services were called to the A24 southbound just after 2pm to a report a pedestrian had been struck.
The pedestrian, named as Cyril Jackman, 90, of Fairbrook Road, Southwater, died at the scene from his injuries.
PC Stu Watson from the Road Policing Investigation team said: “We are keen to speak to anyone who was driving in the area and may have seen the elderly man in the road before to the collision”.
“We need to establish what happened and need to speak to anyone with information.
“Please call 101 quoting Operation Plumstead or email firstname.lastname@example.org”