MELFORT, Sask. -- A truck driver who killed three Saskatchewan teenagers when his speeding semi rear-ended their car in a construction zone has been sentenced to three years in prison.

The boys were driving home from football camp two years ago when Normand Lavoie hit them and caused a chain reaction that pushed their car into another vehicle that hit a flag operator, who was seriously injured.

Justice Mona Dovell said Lavoie's remorse is profound and she noted that alcohol was not a factor.

Lavoie, formerly of Winnipeg, pleaded guilty in May to three counts of dangerous driving causing death and one count of dangerous driving causing bodily harm.

He was sentenced to three years for each teen's death and one year for the flag worker's injuries, but the sentences are to be served concurrently.

In an agreed statement of facts presented in court last month, Lavoie said he was tired and on "auto pilot" because of the flat Saskatchewan landscape.

He also said he didn't recall seeing six signs about the upcoming construction zone and warning drivers to slow down.

"You're keeping the thing on the road," Lavoie told an RCMP officer. "You're just kind of in la la land. Basically I'm there behind the wheel, but I'm not."

The three teens from Carrot River, Sask. -- Justin Gaja, 14; Kristian Skalicky, 15; and Carter Stevenson, 17 -- all died upon impact.

Samuel Fetherston, the 21-year-old flag operator, is still recovering from his injuries.

At Lavoie's sentencing hear in August, Justin's mother, Crystal Gaja, read a victim impact statement in which she said the only thing she looks forward to now is her dying breath.Court also learned that Lavoie's mother and grandmother were killed in a truck-driving crash and he had used their deaths as motivation to become a safe truck driver.