It is possible a man did not feel a 54-year-old delivery driver who was killed when he was trapped under his van, a police officer says.
Mark Lang died in April, more than two weeks after he was injured near Cathays High School on North Road, Cardiff.
Christopher El Gifari, 31, of Aberdare, Rhondda Cynon Taf, pleaded guilty to manslaughter and theft at Cardiff Crown Court.
However, El Gifari will be tried for murder and robbery.
Under cross examination by his defence barrister, Mark Graffius KC, PC Littlewood said damage done to the van was consistent with a "low speed impact".
PC Littlewood agreed that reconstructions showed it was possible that El Gifari had not noticed or felt anything of concern as he drove with Mr Lang under the vehicle.
The barrister said there was a blind spot looking over the bonnet which would have been more pronounced for a shorter driver - the court heard El Gifari is 170cm (just under 5ft 6in) tall.
Earlier on Monday, PC James Littlewood, a forensic collision investigator with South Wales Police, said Mr Lang would have been "clearly visible" in his high viz vest he wore as a delivery driver and said he would have been visible for about 30m (98ft).
Analysis of CCTV footage found that brake lights were on for three frames, equivalent to between 0.12 and 028 seconds and that they were off for the two frames directly before the collision.
The jury also heard evidence from Dr Richard Jones, a Home Office registered forensic pathologist.
He confirmed that when emergency services arrived, Mr Lang was not breathing, with no pulse and in cardiac arrest.
Mr Lang was transferred to the University Hospital of Wales and doctors recorded two wounds to his head.
The court also heard that 14 of his 24 ribs were fractured and he had suffered "nearly complete skin loss on the back".
Mr Lang never regained consciousness and died just after 5am on 15 April, 18 days after he was injured.
The trial continues.