It turned out that 10 children were riding in the trailer.
"My son was driving at the open road speed (100 km/h) so this vehicle was obviously going faster than he was," the father said.
"There was tarpaulin over the trailer, but a little further up the highway three heads popped out from under it. My son just couldn't believe what he was seeing.
There were two adults in the vehicle.
"Their actions just beggar belief. It's impossible to find words to describe their actions," the father said.
He said Marton police later contacted his son to tell him the driver of the car had been apprehended and would be dealt with.