A 12-year-old boy remained in an intentive care unit of an Edmonton hospital Tuesday afternoon after his all-terrain vehicle was broadsided by a truck near Boyle, about 150 kilometres northeast of Edmonton.

Ryan Herchuk and an 11-year-old friend were riding ATVs around 5:30 p.m. Monday, following back-country trails north of the town, when the older boy took the lead in crossing a rural road and was struck by a truck travelling at the 100 km/h posted speed limit.

"This is a very unfortunate incident where a young boy's life is in jeopardy," Boyle RCMP Const. Joe Mandel said early Tuesday.

"Witnesses state that the boy appeared not to have properly braked prior to crossing the highway," he said.

The boy's condition was listed as serious late Tuesday.

Police have seized the all-terrain vehicle to see if the brakes were working properly at the time of the crash.

The boy was wearing a helmet and proper clothing, police said.

They are reminding  parents that children under the age of 14 are not allowed to operate off-highway vehicles like ATVs on public land.

But CBC TV's Briar Stewart, who was in Boyle on Tuesday, said many people told her it's a law that is often ignored in rural parts of Alberta.

People said they often see children as young as seven driving all-terrain vehicles, Stewart reported.