Lawyers for a man who previously pleaded guilty to four counts of dangerous driving causing the deaths of mother and her three young children in Brampton are attempting to challenge a cannabis-impaired driving law linked to the case.
Brady Robertson, of Caledon, Ont., pleaded guilty to four counts of dangerous operation of a motor vehicle in July.
He was charged in connection with a crash in June of last year, where Karolina Ciasullo, 37, and her three daughters — Klara, 6, Lilanna, 3, and Mila, 1 — died after their Volkswagen SUV was struck by a blue Infiniti G35 near Torbram Road and Countryside Drive.
Though he pleaded guilty to dangerous driving charges, Robertson pleaded not guilty to four counts of impaired operation causing death in connection with the crash.
Ontario Superior Court Justice Sandra Caponecchia also found Robertson guilty of impaired driving at the judge-alone trial.
Now, Robertson's lawyers have mounted a constitutional challenge against the drug-impaired driving law, specifically as it pertains to cannabis use. His impaired driving conviction and sentencing are contingent on the outcome of the challenge.
In court Monday, defence lawyer Mayleah Quenneville argued that the legal limit for cannabis usage — five nanograms of THC per millilitre of blood — is both "arbitrary" and "overbroad," and does not accurately reflect impairment for a user based on a single blood sample.
"Even with every intention of compliance with the letter of the law, individuals who use THC, even on an occasional basis, would have to significantly decrease, if not entirely forfeit, the ability to legally operate a motor vehicle, even in conditions where their ability to do so is not impaired," she said.
"The quarrel here is with the law that ignores the evidence and attempts to assign an overly simplistic solution to a complex problem at the expense of innocent people."
Parliament should set policy, not courts, Crown argues
Court has heard that Robertson had about eight times the legal limit of THC in his blood at the time of the crash.
Quenneville cited previous expert witnesses from court, and argued that factors like tolerance level, receptor density and a person's sensitivity to cannabis would all play a role in experiences of impairment — essentially, that someone could be over the legal limit but not actually impaired, especially if they are a frequent user.
"Of course, impaired driving is devastating, and preventing and detecting and prosecuting impaired driving is important, and a worthwhile legislative goal to put it lightly," she said, adding that the defence is not challenging impaired driving as a whole.
"Impairment is entirely dependent on what is happening in an individual's brain. What is happening in an individual's brain is completely different from what's happening in their blood. Blood THC level is simply not reflective of impairment."
In response, assistant Crown attorney Patrick Quilty said the issue should be dealt with at a higher level, and not by individual courts on specific cases.
He also pointed to previous studies used by parliament to establish a reasonable legal limit, and said evidence has shown that there is a correlation between higher blood THC concentration and impairment.
"It's parliament and not the courts that decide what should be criminalized," he said.
Caponecchia has reserved her decision on the matter to a later date. Victim impact statements in the case are expected in December, with the Crown indicating "a large number" of people wish to speak.