The video, taken in Aspull, shows a taxi driver cruising into the right-hand lane of the windy country road - where he stays for around 30 seconds before almost colliding with another vehicle.
James Bradley, who was driving home from work when the near-miss occurred on Scot Lane, can be heard on the film beeping his horn continuously to alert the motorist to his potentially-fatal mistake.
“He was completely oblivious to the fact he was on the wrong side of the road,” he said. “I was flashing him and beeping him - I even sped up to him so I could make him aware.
“I knew there were some blind bends on that road. I could imagine a car just hurtling down that hill - it would have hit him head on. It would have been absolute carnage.”
After around 30 seconds of driving on the wrong side of the road, the taxi driver turns round a bend and almost ploughs into an oncoming car, behind which is a large van.
With just moments to spare, the motorist realises and calmly pulls into the left-hand lane, indicating as he moves over.
“It was unbelievable,” added James. “If the car had been 30 seconds earlier then it would have been a head-on crash.
“I tried my best to get him back over to the right side but he was just paying no notice.
“I had no idea what on earth he was playing at.”
James followed the driver and pulled over to get details about the driver, when he saw the advertisement for Connect Cars, in Middleton, on the side of his cab.
The Wigan Post contacted Connect Cars after James said he had reported the incident.
A spokesperson said that the company received a complaint but that the driver was off-duty when the incident occurred.
“At that time he was not engaged in a pick up or drop off with Connect Cars,” he said.
“With the greatest respect we cannot comment on how he drives in his spare time.”
A spokesman for the road safety charity, Brake, said: “This footage is incredibly concerning, and it is shocking to see such blatant disregard for the rules of the road, which exist to keep us all safe. This is clearly an example of the type of dangerous driving that can, and regularly does, lead to collisions and deaths on the road.
"Thanks to technology, we now have permanent evidence of this dangerous behaviour, and we hope that the police traces the culprit and makes an example of them.”
To view the full video click here