The 25-year-old suffered the ‘life-changing arm injury’ and had his car stolen after being attacked by a gang of men when he pulled over on East Bawtry Road, Whiston, at around 10.50pm on Sunday.
Police said the man, who was travelling alone in a white Mercedes, briefly pulled over close to the junction with Lease Gate Road.
As he got out of his car it was reported that he was approached by a group of unknown men and attacked with a with metal weapon.
The attackers, who got out of a dark-coloured vehicle, then left the scene in the victim’s Mercedes.
The victim was taken to hospital, where he remains in a serious but stable condition.
One resident on Lease Gate Road said: “It’s shocking. I didn’t hear anything but that might be because we’re used to the noise of the road anyway.
“You don’t normally get anything like that around here.”
Another homeowner said they had been told weapon used was a machete but that remained unconfirmed.
A shopowner, who also did not want to be named, said: “I couldn't get parked this morning because of the cordon but by the sounds of it, it was something that was planned.”
In a statement, South Yorkshire Police said: “The victim was taken to hospital with a life changing arm injury. He remains in a serious but stable condition.
“An investigation is under way and officers are currently following a number of lines of enquiry including reviewing CCTV and house-to-house visits.”
Anyone with information should call 101 and quote incident 985 of April 7 or Crimestoppers, anonymously, on 0800 555 111.