Sussex Police has named Chi Hung Wong, from Brighton, as the victim of a fatal crash on the southbound carriageway near Pease Pottage about 9.10pm on Wednesday, October 20.
He was taken to hospital with serious injuries following the incident involving a Citroen C4.
"He has since sadly died," a police spokesperson said.
"His next of kin have been informed and the cause of the collision remains under investigation."
The driver of the Citroen C4, a 55-year-old man from Worthing, was arrested on suspicion of drug-driving. Police said he has been released under investigation, pending further enquiries.
Police have today (November 8), issued a further appeal for witnesses.
The spokesperson added: "Officers are urging anyone who saw what happened or captured any relevant footage on dash cam – in particular any lorry drivers – to email [email protected] quoting Op Maywood.
"A section of the road was closed in both directions due to the adverse weather conditions at the time."