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Trucker's fatigue 'significant' at time of fatal crash, says expert

Most accidents happen between midnight and 8 a.m., says human fatigue specialist
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The Sault Ste. Marie Courthouse is pictured in this file photo.

Gary Tyska likely was suffering from "a significant degree of fatigue" when his tractor trailer collided with a sport utility vehicle three years ago, killing an off-duty police officer, a judge heard Friday.

That was the conclusion of an Ottawa human fatigue specialist, the sixth Crown witness, to testify at the Thunder Bay man's criminal negligence causing death trial.

He has pleaded not guilty to the charge, stemming from the Feb. 13, 2014 collision that took the life of 36-year-old Ontario Provincial  Police Const. David Dennie, outside Blind River.

Following a two-day voir dire, Superior Court Justice Edward Gareau decided Friday to permit the specialist, Clinton Marquardt, to give opinion evidence at the trial, which began Tuesday.

Based on his analysis of information he was provided, Marquardt said Tyska was "significantly fatigued at 6:50 a.m." when the crash occurred on Highway 17.

He said he reached this conclusion "given the degree of sleep deprivation — little sleep on the 13th" —  and the best case scenario of what possible sleep Tyska might have had and the quality of it.

"I tried to maximize the most time for sleep."

His opinion was based on information, including a download from the tractor trailer's electronic control module, fuel receipts and vehicle event authorization forms from Feb.11 to 13, that was provided to him

Marquardt told prosecutor Karen Pritchard he used this information to create a sleep-wake pattern for the driver on Feb. 11, when he left Thunder Bay to travel to Toronto and his return trip, leading up to the crash.

As well, he replicated this pattern for Feb. 8 to 10, and three days prior to that.

He said when he was doing his assessment of whether fatigue played a role, he also looked at performance impairments that could have had an impact.

These included the transport drifting 30 to 40 cms over the centre line at a high speed, no indications of the driver trying to change lanes, stop or turn, and no avoidance such as skid marks.

Marquardt said that statistically most accidents occur between 12 and 8 a.m., involve a lone male driver, non-urban roadways, high speeds and are serious crashes, with no avoidance maneuvers and result in serious injury and death.

The court also heard that Marquardt took the sleep-wake pattern he had recreated and input it in to Fatigue Avoidance Scheduling Tool (FAST), a biomathematical software tool for analyzing human fatigue.

This allowed FAST's mathematics to predict a level of impairment, he said.

At 6:50 a.m. on Feb.23, Tyska had a performance effectiveness level of 76 percent.

Below the criteria of 77 percent is "similar to performance under .05  blood-alcohol concentration, level" Marquardt testified.

During cross-examination by defence lawyer Kate Brindley,  he agreed the formula is only as good as the data that goes into it.

He also agreed that he never met with Tyska nor interviewed him, didn't  know if he had any health problems and didn't measure his brain waves.

Referring to testimony he gave at Tyska's September 2015 preliminary hearing, she asked if he still believed it is possible the driver in this case didn't know he was fatigued.

"Yes," he replied.

The data that Marquardt had appeared to show that two hours prior to the collision that Tyska had two hours of sleep from approximately 2:30 a.m. to 4:30 a.m., the defence noted.

"I factored that into the equation," the witness said.

Marquardt indicated that the accident dynamics were described to him and that's how he had information that there were no pre-crash maneuvers taken by the driver.

Since it's been three years, he said he didn't recall if he had read the collision reconstruction report.

Brindley suggested the vehicle path description he was given indicated the transport had crossed 40 cms over the centre line while travelling at 93 kilometres per hour and collided with the sport utility vehicle.

Marquardt said he couldn't recall if he was told that or had seen it in an accident report. 

She wondered if the point of impact was undetermined whether that would affect his analysis.

He indicated "then I can't relate it back."

A bit later, Gareau asked "if the point of impact was not where you were told would you have to go back to the drawing board, would that change your report?"

"It could," Marquardt responded.

He agreed with Brindley that he had no information about the other driver, that he didn't know Dennie's work schedule or anything that he could assess for fatigue.

The trial continues today.

EDITOR'S NOTE: SooToday does not permit comments on court stories

-Sootoday.com 



About the Author: Linda Richardson

Linda Richardson is a freelance journalist who has been covering Sault Ste. Marie's courts and other local news for more than 45 years.
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