A fatal accident inquiry (FAI) has heard how the victims were killed in 19 seconds when the lorry careered into them.
Crash investigator Mark Hill told Glasgow Sheriff Court this was how long it took from when the lorry changed course until it crashed into the Millennium Hotel on 22 December 2014.
Off-duty nurse Lauren Mykoliw was at the festive market in George Square when she heard a loud bang and thought something had happened to the big wheel before realising that a bin lorry had crashed.
The 28-year-old went to the aid of a taxi driver before speaking to bin lorry driver Harry Clarke, who she said was conscious and had his seatbelt on.
Ms Mykoliw said he told her that he could not remember what happened.
Mr Clarke asked the off-duty nurse if he had had a heart attack. She said: “I asked if he felt unwell before the crash and had blacked out. He answered no.”
Ms Mykoliw added: “He said he remembered sitting at the traffic lights, then woke up where he was. He was pale and looked like he had a shock.”
Erin McQuade, 18, and her grandparents Jack Sweeney, 68, and Lorraine Sweeney, 69, from Dumbarton, West Dunbartonshire, were struck and killed.
Stephenie Tait, 29, and Jacqueline Morton, 51, both from Glasgow, and Gillian Ewing, 52, from Edinburgh, also died.
The inquiry has also heard from paramedic Ronald Hewitson, 52, who was one of the first people on the scene.
He said Mr Clarke was lying on the ground in front of the lorry by the time he arrived.
He added: “From the checks we did, there was nothing obvious. I asked him if he took any medication but I can’t remember his answer.”
Mr Clarke told him the last thing he could remember was someone shaking him after the crash.
The FAI later heard from Robert Soutar, manager of the Anderston depot where Mr Clarke picked up his crew.
Questioned by solicitor general Lesley Thomson, who is leading the inquiry, Mr Soutar said there was no specific training for crews in dealing with an ill driver.
“They would just do as anyone would and call for assistance,” Mr Soutar said, adding that Matthew Telford, one of the lorry crew, contacted a supervisor immediately after the crash.
Questioned about route risk assessments, Mr Soutar said special events in the city centre would be flagged up to drivers but not seasonal events.
The inquiry earlier heard from baker Andrew Wilson who saw a council bin lorry driver in an altercation with another driver earlier on the day of the Queen Street crash.
Mr Wilson said he was on Cowcaddens Road when he saw a lorry driver sound his horn and gesticulate at another driver who had cut in front of him at about 1:30pm.
He said: “It wasn’t until I got home and saw the news [that he thought he should report it]. I’ve no idea if it was the same bin lorry or not.”