A popular Ramsgate father died when the cement mixer truck he was driving overturned off the M25.
An inquest heard Lee Harrington, 39, had not been breaking the speed limit, but the loaded truck had toppled because it had been travelling too fast for the type of vehicle and load on the curving slip road.
After hearing forensic evidence and from other drivers, coroner Roger Hatch ruled his death, from head and chest injuries, was accidental.
Lee Harrington, from Ramsgate, died in a crash on the M25
He explained legal representatives were in court because Mr Harrington's family "are concerned whether he should have been driving that particular lorry on that particular day".
Mr Hatch added: "I understand they will be pursuing a civil claim in due course."
The Renault vehicle had no defects. Mr Harrington had no traces of alcohol or drugs in his system.
"I cannot rule whether a criminal liability exists. That is for other courts to deal with in due course..." - coroner Roger Hatch
Driver David Avery had followed traffic off the M25 at J5 onto the A21 slip road at Chevening, where the motorway roadworks 50mph restriction ended.
He said he had glimpsed the Renault in front. Next time he saw it, it was on its side and had hit the crash barrier.
Mr Avery had gone to check Mr Harrington, a divorcee who lived with 42-year-old partner Lucy in St James Avenue.
He said: "He was out of the cab, with his head facing down, with the crash barrier and the lorry on top of him."
Attempts had been made to free Mr Harrington, but it had not been possible.
Motorist Kim Phipps had followed the cement mixer and had been on the inside lane of the slip road, with the Renault in the outside lane.
She had no concerns about Mr Harrington's truck until, on the bend, she had seen its wheels leave the ground.
She said how she had felt the driver had been "going a bit fast". The lorry had gone onto its side and there had been a large cloud of dust, she added.
A slip road of the M25 was shut after the van overturned. Picture: Highways Agency
The Renault's tachograph revealed that in its final 550m, it had accelerated from 47mph up to 53mph.
Robert Giles, a forensic collision investigator with Kent Police, said: "I would say 50mph is an excessive speed for such a vehicle, particularly if the vehicle is loaded."
The effect could have been exacerbated by displaced aggregate inside that would have lowered the speed at which the Renault would have rolled, he said.
"Depending on the height of the centre of mass, rollover could occur between 48 and 55mph," added the investigator.
Mr Hatch said: "It is apparent that the vehicle was travelling at a speed in the order of 50mph on the bend and as a result of that speed, the vehicle went over on to its side.
"I cannot rule whether a criminal liability exists. That is for other courts to deal with in due course."
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