Mr Dingle said car the ran over Ryan's shoulder and pushed him down onto his stomach.
"It's driven up his lower back right up and missed his head and gone over his shoulder."
The 5-year-old boy still had a swollen face, a few stitches and shallow abrasions but would be discharged from Starship Hospital tomorrow, he said.
Mr Dingle said Ryan "was known" to chase cars before and had been warned a number of times.
"I've told him before, you're going to get run over."
He said Ryan was lucky to be alive.
"He's very lucky. It's an unfortunate accident and it could have been a lot worse.
"You always hear about people running over their children in the driveway and I'm always aware of that but you don't expect to be driving forward and have your own child run along trying to jump in the side of the car," he said.
He hoped Ryan would be "quite scared of getting even close to a vehicle for a long time".