At 3pm he walked to a local bottle shop with his friend, Daniel Newman, to buy more vodka cruisers.
They returned and continued drinking.
By 7.30pm Davidson made the fateful decision to get behind the wheel of his Mitsubishi Triton to withdraw some cash from an ATM about 3km away. He was at least three times the legal alcohol limit and drug-affected.
His friend, Newman - who was never charged - sat in the passenger seat beside him.
CCTV captured the ute pulling up to the Budget Petrol station at North Rocks before harshly accelerating out of the carpark and driving straight through a red light as it headed down Bettington Road.
A witness reported the vehicle tailgating her and swerving from side to side as it tried to overtake.
In her rear-view mirror she could see two shirtless men who were laughing.
The ute then sped through a roundabout using the wrong side of the road to overtake the car.
Davidson was "quite animated" and laughing when he stuck his middle finger up at another motorist.
A judge would later say the erratic manner of his driving made the impending tragedy about to unfold "inevitable", but that no one could have imagined just how horrific it would be.
At 7.50pm, seven children were walking to a local IGA store on the warm summer evening to get some ice-cream after popping out of a family birthday party in Telopea.
One of them was riding a bike while the others strolled carefree along the footpath on the edge of Oatlands Golf Club, separated from its greens and fairways by a metal cyclone fence.
Nearby, after stopping briefly for a red light at the intersection of Bettington and Pennant Hills roads, Davidson drove across four lanes of traffic before the lights turned green.
Soon after, the ute approached a sharp right hand bend on the sloping road while travelling at speeds in excess of 130km/h.
It was at this point he completely lost control.
The heavy-duty vehicle careered into the backs of all seven children who didn't see him coming.
Siblings Antony, 13, Angelina, 12, and Sienna Abdallah, 8, and their cousin Veronique Sakr, 11, all died at the scene.
Another young child was left in hospital for 80 days and now lives with a permanent brain injury.
Analysis of the ute's computer data revealed the vehicle hit a top speed of 133km/h just seconds before the collision, at least 80km/h over the speed limit.
The accelerator was fully depressed and the brakes of the vehicle were not applied at any time in the five seconds preceding the collision, the data confirmed.
Davidson would blow a blood-alcohol reading of 0.182 at the scene of the crash before returning a second reading of 0.15 at Castle Hill police station.
A witness at the chaotic scene told police he jumped out the car when it came to a stop 90m away and cried: "What have I done? I have killed people. I am going to jail."
But he couldn't remember any of it, later saying it was all a "blur".
He was so dazed that his first recollection of what happened was having his fingerprints taken at Castle Hill police station.
On Friday, Judge James Bennett sentenced Davidson, now 31, to a maximum of 28 years in jail with a non-parole period of 21 years after he pleaded guilty to charges including four counts of manslaughter.
"It breaks my heart that I have hurt this beautiful family and I am responsible for this horrible accident," he wrote.
"Waking up every day knowing I am responsible for all this … is the worst punishment and will never go away.
"I would do anything to relive that day and be sober and never leave the house.
"I am so sorry for all of this and hate what I have put you through and will never go away.
"I have wanted to apologise for all this since the start of all this."
The families want Davidson to think about what he's done while he spends the next two decades behind bars. He will be 50 when he is first eligible for release.
"We all hope that Mr Davidson can use this time in jail to really reflect on what he's done and truly understand the consequences of his actions," Veronique's mother, Bridget Sakr, said outside court on Friday.
"In particular how the use of drugs and alcohol has devastated so many families, communities and indeed all of us here.
"We also pray that our tragedy highlights to the Australian community the dangers associated with the glorification of drugs and alcohol by our society."