A man who struck and killed a conservation officer on a Saskatchewan highway says the court didn't properly consider his background of poverty, abuse in a residential school and struggle with alcohol when he was sentenced.

Blaine Taypotat was given 9 1/2 years for running down Justin Knackstedt in May 2013.

Taypotat's appeal of his sentence is to be heard Thursday in Regina.

Documents filed by Taypotat's lawyer argue the trial judge misapplied the Gladue factor, a sentencing principle which requires courts to take into account an indigenous offender's background.

"The environment Mr. Taypotat grew up with was fraught with alcohol-induced violence," wrote Josephine de Whytell.

She said Taypotat's biological parents couldn't care for him due to alcoholism and he was mistreated by his adoptive family. Alcohol became "the coping mechanism."

"Mr. Taypotat was given his first beer when he was six or seven years old by an older brother who had just been released from jail," she wrote.

De Whytell said Taypotat, 38, was abused at a residential school where he spent eight years and that the collision happened shortly after he had received compensation. It brought back memories that were fresh in his mind at the time he hit Knackstedt, she said. He was also heading to the funeral for a cousin who had been murdered.

The sentence "is demonstrably unfit" and should be eight years, de Whytell will argue.

Knackstedt, 23, was helping police direct traffic at a road block set up after a crash south of Saskatoon.

Documents filed by the Crown say the conservation officer was hit from behind and thrown 41 metres. His body slid another 38 metres before ending up in a ditch.

The Crown said Taypotat sped past the roadblock and drove down the middle of the two-lane highway while being pursued by police. That's when he struck Knackstedt.

"Rather than stop to see if he could help, the appellant sped away toward Saskatoon, only stopping when he rolled his vehicle and it burst into flames," wrote prosecutor Andrew Davis.

A police officer and a bystander crawled into the burning vehicle to cut Taypotat loose and drag him to safety.

Court documents show his blood alcohol level was more than three times the legal limit.

Taypotat pleaded guilty in December 2014 to manslaughter and impaired driving causing death and was sentenced last year.

The Crown noted that a Gladue report was prepared by a PhD candidate from the University of Saskatchewan history department, whom the trial judge found was unqualified to give expert opinion evidence. She had not prepared such reports before nor had she reviewed any prepared by anyone else.

The Crown didn't challenge the admissibility of the report, but did indicate that not everything in the report was corroborated.

Davis said the judge did not make a mistake. He said the sentence was "an appropriate response to this egregious crime."

"The consequences of the appellant's actions could hardly be more serious or tragic," said Davis.

"His culpability in the offence is extremely high. The sentence was fit and it was in keeping with recent countrywide trends in sentencing similar offenders who commit similar crimes."