'Missing piece of the jigsaw' into Prior's Court minibus crash
Inquest into the deaths of three staff members concludes
"Something catastrophic" happened to a Prior's Court School minibus just before it was hit by a lorry on the M4 last year.
However, a coroner, crash investigators and vehicle experts have been left "scratching their heads" as to how the minibus suddenly lost power.
Autism practitioners Lorraine MacLellan, 60, and Jason Aleixo, 44, died in the collision, while 52-year-old vocational instructor Catherine Gardiner – who was driving the minibus – died in hospital the next day.
The collision, between the minibus and a lorry, occurred on the M4 eastbound carriageway between Hungerford and Chieveley a year ago today – October 11, 2018.
The coroner's court heard on Wednesday that the hard shoulder had been closed off to allow Highways England to replace a barrier.
Yesterday (Thursday), the inquest heard that the barrier blocking the hard shoulder had been installed the day before the crash.
The coroner's court heard that Mr Aleixo and Mrs MacLellan had died from multiple injuries sustained in the crash. Miss Gardiner died from a traumatic brain injury at the John Radcliffe Hospital the following day.
Dashcam footage from lorry driver Graham Scivier was played to the coroner’s court on Wednesday.
It showed that Mr Scivier had been travelling at 53mph in the inside lane when he was overtaken by another lorry, driven by Stephen Hall.
Mr Hall’s lorry then pulled in front of Mr Scivier, but swerved back out into the middle lane a few seconds later.
The inquest heard that with his vision obscured by the large vehicle in front, Mr Scivier had no time to react to the Prior’s Court minibus that had appeared in front of him.
Pc David Hannan, based with the forensic collision unit for Thames Valley Police and Hampshire Constabulary, said yesterday that the time between Mr Scivier seeing the minibus and hitting the brakes was approximately 1.4 seconds.
It was then another half second between him hitting brakes and hitting the minibus.
"It would have felt instantaneous to the driver," Mr Hannan said. "He was presented with a scenario where there was very little he could do, but he has reacted quicker than the autonomous braking system fitted.
"To his credit the fact that he has reacted so quickly given the scenario, I think he deserves credit for that.
"I can't say for sure but it's possible that his rapid reaction might have saved some of the occupants lives."
Mr Hannan said that officers had tested another school minibus to try and replicate the sudden loss of power, but had been unsuccessful.
Berkshire coroner Heidi Connor said there question marks over how the minibus had slowed and that there was "a missing piece of the jigsaw".
Mr Hannan said that the minibus' brakes had been applied in the matter of seconds before the lorry hit it.
"The brake lights are clearly on. The driver has suddenly applied some braking. At what point the breaking commenced we can't say.
"From what we know we have a fully functioning minibus travelling at a fairly constant speed and nothing in front of it causing concern.
"The driver herself, we are told, is familiar with driving this vehicle and has had additional training. No medical history that would suggest a concern.
"However, the area that is very difficult to get away from is that we heard immediately before the incident that the driver said 'Oh my God! Oh my God!' which can only suggest that something has happened beyond that driver's control or ability.
"Whether it's by the driver or the vehicle, I can't say, but clearly something catastrophic has happened and as a result of that the driver has braked."
Highways England team leader for operations and maintenance Matthew Salt was questioned over the hard shoulder closure, put in place to repair a barrier.
Mrs Connor said: "As I understand it, the M4 smart motorway is not going to have a hard shoulder."
"Part of it," Mr Salt replied.
Under questioning from lawyers representing Miss Gardiner's family about what mitigation measures were in place, he said: "There are hard shoulder closure signs, at a distance, that we have warned drivers that the hard shoulder is not in place."
And discussing the lack of escape routes for drivers in difficulty, he said: "The barrier is pinned together and that's what gives it its strength."
The inquest heard that six faults had been identified in the vehicle's diagnostics but all had been triggered after the crash.
Asking Ford Motor Company engineer Adriaan Moolman about the system, Mrs Connor said: "This is a really complex system that triggers for many things, such as a light bulb not working.
"One of the missing pieces of the jigsaw for me is why this vehicle came to a sudden stop".
Mr Moolman replied: "At the end of the day we have to look at the data. The data shows no indication of what could have gone wrong before the crash occurred."
The inquest heard that the minibus had not run out of fuel and there was nothing to show that the diesel particulate filter had overheated.
The coroner's attentions then turned to the minibus' dual mass flywheel protector, which Mr Moolman said operates at a frequency below the normal running speed of the engine.
He said the system helped get an engine out of that range as quickly as possible and would shut it down at a point where the engine was unrecoverable.
"Where it drops below normal speed it then shuts the engine down, In that case we offer the driver two alternatives to get it up and running again."
He said these were to turn the engine off and back on again, or via a bump start.
However, Mr Moolman said that a minibus travelling at 50mph on the motorway would not have triggered the system.
He said: "The DMF protection is deemed a driver error, not an error within the vehicle. There would be a fault code for it but basically we deem that as a driver error."
Under further questioning, he added: "We just don't know what happened at that point in time... I don't know if there was anything else mechanically wrong with the vehicle but from an engine point of view, if you get to the stage where the DMF kicked in it could be driver error."
Mr Moolman said he had not heard of the system triggering accidentally at higher speeds or revolutions.
"It's potentially possible although I have never heard of any reports of this happening. If it did we would definitely know about it, it would happen more frequently," he said.
But he added that a fatal crash involving a Ford Transit being hit from behind had occurred last month.
He said: "I'm aware of one other incident where a vehicle was driving along the motorway and slowed down and got hit from behind but there were no fault codes. It was a different vehicle, different engine and everything.
"When we develop these vehicles we go through very, very rigorous testing."
The inquest heard that a fault code for DMF failure was not logged on the vehicles. It also heard that a batch of Ford vehicles had been recalled after fuel injectors had been assembled incorrectly.
However, the minibus involved in the crash fell outside of the date range and a fault code would have triggered if this had been the case.
The inquest also heard that school minibus' engine had started and run normally when tested after the crash.
Mrs Connor asked Mr Moolman "might it be worth having a code trigger, given that you trigger a code for a light bulb not working?"
He replied: "After now I can definitely see it might be worth having a code there."
Pc Hannan added: "The fact that you have a system designed to kill the engine, it seems strange to myself why you would not want a record of that.
"As we have heard from Ford, the only reason that system would kick in is due to driver error. I would expect you would want to capture that data."
Concluding the inquest as road traffic collision, Mrs Connor said: "The reason remains unclear after a detailed investigation, although on the balance of probability a problem with the vehicle appears to be more likely than driver input."
Mrs Connor said she had no concerns with the closing the hard shoulder for works and the times it was carried out.
Of concern, however, was the lack of regulation to ensure that the works were completed without delay, adding that the only incentive appeared to be commercial for the contractor.
Mrs Connor said that she would be asking Ford to review the fault codes with the DMF system.
She also requested that Ford carry out a full inspection of the vehicle alongside the fault codes. This, she said, was "to see if any further light can be shed on why this vehicle suddenly started to slow down so suddenly".
