A five-year-old Edmonton boy was dropped off from a school bus alone and 23 blocks from his daycare, in a case school officials admit is a “serious” error.

Casey’s mother Simone Cardinal says her son is “traumatized” by the incident.

"These last couple of days he's been very, very clingy. He’s been traumatized."

Cardinal says the bus driver skipped her son’s daycare stop. An hour after he was supposed to be there, she got a call from the daycare that her son hadn’t arrived. She panicked.

Casey had been dropped off at the end of the bus route, in a residential area about four kilometres away from his daycare. Another mother saw the boy standing alone on the sidewalk, took him inside and called police.

Cardinal is grateful the woman stepped in to help her son.

"It's getting to be dark...it's cold...he doesn't recognize anything,” said Cardinal.

She met with school officials to figure out what went wrong.

“The driver failed to do his job correctly and it was a human error,” said Debbie Hunter, director of student transportation services at Edmonton Catholic Schools.

"This is a serious student safety issue that we take very seriously."

The driver has been removed from the route, and the bus company, First Student Canada, issued an apology. The company says it wasn’t the usual driver but one who had done the route before.

"That apology doesn't matter. I want to hear an apology from the bus driver," said Cardinal.

The bus company denies there is a procedural problem, saying the incident comes down to “driver error.”

But it’s not uncommon for a child to go missing from a bus. Edmonton Catholic officials say all five of its contracted bus companies have lost track of a child at least once.

That is no comfort to Cardinal, who worries it will happen to another child.

“A child should never be left alone.”

With a report from CTV Edmonton