Theman, who has been named locally as Leonard Lowe, died after being struck by a silver Seat Ibiza car on the Westbound carriageway at Wickford, at just before 10pm on Sunday.
Paramedics battled to save Mr Lowe, who lived on the Hovefields travellers site and was in his early thirties, but he was declared dead at about 10.15pm.
The 47-year-old male driver was taken to Basildon Hospital with minor facial injuries He was discharged and is now recovering from shock at his home in Southend.
Michael Knight, owner of Gemini Kennels, in Hovefields Avenue, Wickford, had known Mr Lowe, who was known as Lucky, for a number of years.
He said: “He was a really nice guy and we had known him since he was a young lad.
“His family are very nice people.
He was just a very pleasant young man. I would describe him as a gentle giant.”
The accident happened opposite the Shell petrol station, on the eastbound carriageway.
Other friends of Mr Lowe said he was devoted to his wife and family and was a true horseman.
Police shut the road in both directions until 5.30am yesterday while collision investigators carried out their inquiries.
One driver who witnessed the aftermath said: “I was a few cars back and it was horrific. All his family were hysterical.
“Police shut the road and I was there for two hours. The police helicopter was above.”
A spokesman for the East of England Ambulance Service, said two ambulances attended with medical volunteers.
He said: “One patient was taken to Basildon Hospital with non-life-threatening injuries.
“Paramedics tried everything they could to try to save the second man, but he was pronounced dead at the scene.”
Police are appealing for any witnesses to contact the serious collision investigation unit on 01245 240590 or e-mail collision firstname.lastname@example.org