The Supreme Court of Canada heard arguments on Thursday about what constitutes reasonable grounds to ask for a breath sample in a case involving impaired driving causing death in Alberta.

The hearing in Ottawa stemmed from the case of Bennett Rhyason, an Alberta man convicted of impaired driving causing the death of a teenager in Sherwood Park on July 31, 2004.

Rhyason was also convicted of operating a motor vehicle while having more than 80 milligrams of alcohol per 100 millilitres of blood.

In April, the Court of Appeal of Alberta increased his sentence to three years after the Crown appealed his initial sentence of 18 months.

Rhyason was driving when he struck and killed Jimmy Shelstad, 17, a pedestrian who had been crossing the street at a marked crosswalk at a controlled intersection.

The police officer who arrested Rhyason had detected an odour of alcohol on Rhyason's breath and demanded a breath sample, even though Rhyason showed no balance or slurring problems.

In court, the officer testified: "I formed the opinion that Mr. Rhyason had consumed alcohol in such a quantity that impaired his ability to operate a motor vehicle, and subsequently caused the death of the victim."

Breath samples showed Rhyason was impaired, with more than the legal limit of 80 milligrams of alcohol per 100 millilitres of blood.

Shelstad was returning home from a party when he was hit. The court heard he was thrown more than 17 metres and there were no skid marks on the road.

According to testimony provided by friends, Rhyason had been drinking with three friends in downtown Edmonton that night and they had ordered about three rounds of highballs at one bar, with three drinks per round.

One friend estimated that Rhyason would have had between seven and 10 drinks in a couple of hours before the three moved on to other bars.

A decision in the appeal is expected in about four months.