Two Australian brothers aged 10 and six drove 100km (62 miles) along a busy New South Wales highway in a bid to make a surprise visit to their grandfather.
Startled motorists called the police after seeing the boys alone in the car.
They had travelled over two-thirds of the way towards their destination, near Moree, when police pulled them over.
"They appeared to be driving normally, certainly better than probably some other people on that road," Sgt Matt Clifford of the Moree police said.
The two boys took their grandmother's car and set off up the Newell Highway, the Sydney Morning Herald reported.
When police stopped them, the two boys did not seem to think they had done anything wrong. "They weren't upset or crying or anything like that," Sgt Clifford said.
He said he was amazed that the older brother managed to see over the dashboard of the car, an automatic station wagon.
"He wasn't an overly tall kid," he said.
Police gave the 10 year-old a warning, but further punishment was left to the family.
"I'm sure granddad and grandma, if not mum and dad, might have their own little chastisement for them," Sgt Clifford told the newspaper.