'Overestimation of ability and underestimation of risks': Toxicologist testifies in impaired driving trial

A toxicologist testified Thursday at the trial of a Desden, Ont. woman who is facing several charges, including impaired driving, in connection to a fatal collision.

Arielle Wall, 21, is on trial in relation to a single-vehicle crash on Longwoods Road, west of Lousiville that claimed the life of Gabrielle Emery, 19, also of Dresden, on April 12, 2021.

Wall has been charged with impaired driving causing death, operation while impaired over 80 (milligrams of alcohol in 100 millilitres of blood) causing death and dangerous operation causing death.

Rachelle Wallage, a forensic toxicologist with the Centre of Forensic Sciences testified remotely Thursday into a Chatham courtroom.

Wallage wrote a “letter of opinion” based on the results of three different tests — a blood sample, a serum sample and a breathalyzer test.

Using them, Wallage “projected” Wall’s blood alcohol concentration (BAC) at the time of the accident to be in the range of 58 to 127 mg of alcohol in 100 ml of blood.

Anything over 50 BAC, Wallage terms as “significant” impairment.

“In my opinion a person within that BAC would be impaired to operate a motor vehicle,” Wallage testified.

When asked what impact impairment has on a drivers’ ability, she said it results in “overestimation of ability and underestimation of risks” and “deterioration of the skill set.”

Assistant Crown attorney Nick Bazylko told the court on the night of the accident, it was midnight, thus very dark on the rural road, which has numerous bends and it had been raining so the road was wet.

Defence lawyer Ken Marley asked Wallage about other factors not included for consideration, like Wall’s tolerance or limitation for alcohol, whether or not she was on medications, or if she drank shortly before getting behind the wheel.

“I don’t know the drinking scenario,” Wallage testified.

Marley told the court he believes Wall’s BAC was lower at the time of the accident versus when the sample was taken, more than an hour later in hospital.

He noted the reports and testing don’t “account” for whether or not Wall was drinking within 15 minutes of driving.

Bazylko submitted 11 images of the crash scene into court as the final exhibit in his case.

Marley declined to call any evidence in his clients defence so closing arguments will be held Friday in court.

Once the criminal court case is concluded, Wall also faces charges of stunt driving and speeding under the Highway Traffic Act which Marley says will be dealt with a provincial offences court.