Robert Malcolm Jones, 48, of New Park Road, Castlefields, hit the back of the Freelander as it slowed down after the clutch failed, causing it to flip over on to its roof and slide down the road, Mold Crown Court heard.
The driver of the Freelander, 69-year-old Kenneth Gordon Brereton, was trapped in the vehicle and died later in hospital while his wife Rosalind – whose last memory before waking up in hospital was picking up her phone to call for help – was thrown out of the car.
The couple, from Rossett, North Wales, had been making their way along Llanypwll Link Road, near Wrexham, on February 6 last year towards the home of Mrs Brereton's mother, who had died a few days earlier.
Jones denies a charge of causing death by dangerous driving and causing death by careless driving.
Mr Brereton suffered a brain injury, was taken to hospital at Wrexham, but transferred the same day to the University Hospital of North Staffordshire at Stoke on Trent where he died on February 24.
A forensic collision examiner concluded that the defendant was travelling at between 44mph and 51mph, he would have had a clear and unobstructed view of the collision scene for 240 metres, which would have been more than ten seconds.
It was the prosecution case that defendant would have had time, given the glare of the low sun, to adapt or modify his driving. He could have used the sun visor, reduced his speed, or if necessary, stopped his vehicle.
Mr John Philpotts, prosecuting, said that after the collision, the sun visor of the van was in the up position and the defendant said that he was not sure if he had used it.
Jones told the court that he had not seen the other vehicle until the accident happened and he had no time to apply his brakes. Asked if he was looking where he was going, he said that he was looking ahead throughout.
He was asked if he was prevented from seeing the vehicle ahead by the sun.
Jones replied: "I don't know. Did it merge in to the terrain that surrounded it? It was a green vehicle against a green background."
Jones, who said he was an experienced driver who had been driving since he was 17, told defending barrister Kim Halsall that in interview he had tried to remember everything but it had been difficult.
"Everything was such a blur after the event, maybe because of the shock," he said.
Jones said that it was not a case that he was blinded all the way along the road.
The trial continues.