Mathew Crook, of Albatross Way, Blyth, was charged after his Ford Transit van hit a Subaru car head-on.
The car was being driven by 30-year-old Barry Carmon, known as Baz.
On Monday, Newcastle Crown Court heard that on the night of April 8, 2017, Crook, 26, turned onto the northbound carriageway following a meal with his partner at The Cook and Barker Inn, Newton on the Moor, but headed in the wrong direction – southbound.
The collision happened less than a minute later and one of the witnesses, Ian Walters, said he called the police at 9.52pm immediately afterwards.
Mr Carmon was pronounced dead at the scene. He was a car enthusiast and friends and family have held numerous tributes since his death.
Crook has pleaded guilty to causing death by careless driving, but he denies the charge of causing death by dangerous driving.
He broke down in tears during cross-examination yesterday afternoon when prosecutor Sue Hirst was describing how he went to pick up his partner from the front of the pub after walking to where the van was parked nearby, but he was able to resume following a short break.
The sat nav he was using had audio and he said when asked by defence barrister Christopher Knox that he followed the instruction to turn right and did not realise he was on the wrong carriageway until he saw the headlights of Mr Carmon’s car as it headed towards him.
He said he does not have a clear memory of what happened leading up to the collision – he was in hospital for a couple of months afterwards and his injuries included a head injury.
Crook said: “It’s all incredibly unclear and anything not out of the ordinary doesn’t stand out.”
During cross-examination, when Miss Hirst referred to a picture showing the sign at the relevant junction saying a dual carriageway is ahead, he agreed that the sign was clear on the ‘well-lit picture’.
But he said he could not answer the question when she asked him why he did not see this sign on the night of April 8, 2017.
He added that if he had seen anything to make him aware that he needed to go to the central reservation and then turn right to go on the A1 southbound, he certainly would have taken this action.