PULLING the handbrake of a runaway bin lorry might have led to more injuries or deaths, an inquiry has heard.

Expert witness Mark Hill said that if the passengers in the lorry - Henry Toal and Matthew Telford - had applied the brake the lorry may have continued along the pavement as the wheels locked.

Glasgow Times:

This could have led to more passengers being struck.

Mr Hill, a consultant with the Transport Research Laboratory, said that the passengers acted in a "natural" and "understandable" way given the trauma they endured.

He also said that an emergency stop button, which Glasgow City Council bin lorries are not fitted with, would not have prevented the crash but would have "mitigated the consequences and the duration".

Glasgow Times:

Erin McQuade, 18, her grandparents Jack Sweeney, 68, and his 69-year-old wife Lorraine, all from Dumbarton, died when the bin lorry mounted the pavement and ploughed into shoppers on Queen Street on December 22 last year.

Stephenie Tait, 29, and Jacqueline Morton, 51, both from Glasgow, and Gillian Ewing, 52, from Edinburgh, were also killed.

All six died at the scene from multiple injuries.

The council bin lorry was being driven by Harry Clarke.

During the fifth day of a Fatal Accident Inquiry (FAI) into the tragedy, Mr Hill, a former police officer and expert on the human factors involved in road collisions, said that the crew had "very little opportunity" to intervene and stop the crash.

Mr Hill said that factors which affected the passengers included: a fear of being harmed; the fact that the vehicle was unstable; and a perception that the crash would have ended earlier than it did, when the lorry initially struck the wall of the Virgin Money building.

In a report, shown to the inquiry, Mr Hill said it was "physically possible" to apply the hand brake.

But he said that the lorry would have "progressed along the building line as it slowed with the wheels locked on a wet surface".

Mr Hill added that the "casualty count is likely to have been significantly higher".

Mr Telford and Mr Toal have previously told the inquiry that they did not attempt to pull the handbrake.

Mr Telford said driver Mr Clarke, who was described as being "slumped" in his seat, was obstructing it.

Mr Telford punched Mr Clarke on the back and screamed at him that he was "killing people" in an attempt to rouse him.

Both men said they kept their seat belts on as the lorry veered out of control.

Mr Hill agreed that their reactions are "what most people are likely to have done".

Solicitor general Lesley Thomson QC said members of the public hear about people doing "extraordinary things" in the face of danger and that some might have been wondering why the passengers in the lorry didn't do more.

But expert Mr Hill said that their reaction was "natural" and "understandable".

Mr Hill added that an emergency stop button or switch would not have avoided a crash.

He said: "Had there been access to an emergency stop switch to disable the vehicle, operated by either passenger, this might not have entirely averted the event but would most possibly have mitigated the consequences and the duration."

Mr Hill told the inquiry that currently no training exists, within the transport industry, on how to cope with an incapacitated driver.

He added that, while it would have challenges, developing this would "only be for the good".

Mark Stewart QC, who is representing the Sweeney and McQuade families, asked: "With foresight, one could equip people to intervene in a particular tragedy?"

"Yes," replied Mr Hill.

The inquiry, before Sheriff John Beckett, continues.

Watch The George Square incident as it unfolded: