The 12-year-old is now fighting for his life in hospital after the horrifying incident unfolded.
Now his distraught mother is urging other parents to stop their children playing risky games on busy roads.
The sickening video begins with children jumping swimming a pond by a motorway.
The excited youngsters crawl out up a grass verge and run onto the road – narrowly missing speeding cars – to get a run up to jump back in.
One of the kids narrowly misses being hit as he tries to reach a central reservation between the two lanes of traffic so he can sprint back across the motorway and leap into the water.
A Good Samaritan also stops to start practicing cardiac massage in a desperate attempt to save the child’s life.
The accident happened on the BR116 Presidente Dutra motorway in Nova Iguaca northwest of Rio on Monday afternoon (February 22).
The youngster was said today (February 24) to be “critically injured” but still alive.
Locals blasted the parents of the children on social media sites, with one saying: “How can they let their kids do something as mad as this?”
Another added: “The driver who knocked that poor child over is going to suffer trauma for the rest of life.”
But another who commented on a YouTube site where the video has been posted wrote: “I know the family of that boy.
“He is a neighbour of mine and his mum is a single mum who has five children to look after.
“She is not at fault. She was working to put food on the table for her kids.”
The boy”s mother posted tragic photos of the youngster rigged-up to tubes as he lies in a hospital bed.
Jacqueline Menezes urged friends to pray for her son.
She said: “I hope this serves as a lesson to the other kids who were with him to stop going to that bloody lake.”
“Those who know me know of my struggle to raise my five children and they know about my situation.
“Those who don’t know me shouldn’t throw stones.”