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One of the most common misconceptions is that a failed breath test is conclusive evidence of guilt that can’t be challenged in court. Nothing could be further from the truth. Although Parliament  and the courts have recently taken to steps to severely limit defences based on “evidence to the contrary” wherein an individual attempts to dispute the accuracy of the readings with evidence of modest consumption, my experience has been that factual innocence rarely plays a very significant role in the successful defence of these charges. Judges and courts have always been skeptical of the so called “two beer” defence and the better defence strategy has always been and remains constitutional challenges to either exclude the readings or stay the charges.

Impaired Driving Lawyer Toronto





In fact as the law now stands, an accused is, except in very narrow circumstances, disentitled from challenging the breath readings based upon his account as to what he consumed. This is so even though an expert might otherwise be called to render an opinion as to factual innocence. The Supreme Court of Canada’s landmark ruling of R. v. St-Onge Lamoureux, 2012 SCC 57 (CanLII), details the ways in which challenges can be made to the results of a breathalyser test. Simply stated the present focus of a defence “on the merits” must be based on demonstrating operator error or machine malfunction. The onus on the accused is to demonstrate a reasonable scientific possibility the breath tests are unreliable. He need not go further and also show that, forensically, he would have been under the legal limit. 

Obviously in cases where the defence intends to directly challenge the breath results every effort therefore must be made to obtain all the maintenance and calibration data. As one judge recently put it, 

“when a machine purports to provide the sole proof that a person has committed a criminal offence which has enormous consequences on a person's life, it behoves counsel to make every inquiry and leave no stone unturned to determine the machine was operating correctly."

Generally speaking there are four basic constitutional issues that are commonly engaged in the successful defence of drinking and driving cases: arbitrary detention, unreasonable search and seizure, right to counsel and the right to be tried within a reasonable time. Here are some examples of cases involving particularly high blood alcohol readings that I have successfully defended on these grounds.
1. Arbitrary detention
R. v. R.P.
Client arrested in a parking lot just as he exited a local bar. After failing a roadside breath test was taken to the station where he provided two breath samples which were twice the legal limit. Charged accordingly with over 80.
Despite Crown’s initial position which sought a period of jail, case was eventually resolved following a judicial pretrial by way of a plea to the Highway Traffic Act offence of careless driving. Insofar as the entire event had occurred upon private property an issue arose relating to the power of the arresting officer to make a breath demand in circumstances where the motorist was If you are uncertain about your rights and you really need to win the case to keep your licence and avoid a criminal record then call me.  not on a “highway”. There were also an issue relating to a possible arbitrary detention of the motorist based on his previous criminal record which the officer likely discovered by running a license plate check sometime earlier in the day. Lastly, in my discussions with the Crown through previous correspondence and during discussions in chambers with the Judge, I emphasized that I would seek to exclude the breath readings due to the improper administration of the roadside breath test which took place without any inquiry as to the time of the accused’s last drink. The failure to determine this, which is mandated in officer training, suggested the possibility of a “false positive” test due to unabsorbed residual mouth alcohol thereby bringing into question the officer’s reasonable and probable grounds to arrest.
2. Unreasonable Search
R. v. D.H.
Client had been drinking and was involved in a serious accident after he ran a stop sign on a rural road. Both vehicles were written off and he was taken to the hospital by ambulance. Police conducted a forensic examination at the scene which involved the warrantless seizure of the “black box” in the client's car. An expert report concluded that the accused’s vehicle had been traveling at a dangerously high rate of speed on the dark and wet country roads. Client charged accordingly with impaired driving, over 80 and dangerous driving.
All charges dropped in exchange for a plea to careless driving. Crown conceded at pretrial that over 80 would be difficult to prove due to marginal readings, accepting the recognized 10% error tolerance of breath device. Crown also accepted that the accident reconstruction report may not be admissible due to the unauthorized seizure of the black box from the accused vehicle.

3. Right to Counsel
R. v. D.C.
Client arrested at the scene of a mid afternoon accident near a construction site in a quiet residential neighbourhood. His car had inexplicably rear ended a parked construction vehicle. Damage was extensive and he may have been knocked out in the collision. A neighbour phoned 911, the police arrived and after detecting an alcoholic odour on the motorist’s breath, arrested him and took him to the station where he provided two breath samples which were both more than three times the legal limit. Client charged with impaired driving and over 80.
Case dismissed. Trial judge granted the defence application to exclude breath readings based on a breach of the accused’s right to counsel. Judge accepted that insofar as the arresting officer made no effort to record the supposed waiver of counsel the court was thereby deprived of an opportunity to determine for itself whether or not the police officer's opinion was objectively justified. Once the excessive blood-alcohol readings were accordingly excluded from the equation, the trial judge agreed with the defence submission that the charge of impaired driving was not proven beyond a reasonable doubt since the concussive facts of the accident may well have contributed to the accused’s apparent state of “impairment” after the crash.
4. Right to be tried within reasonable time
R. v. M.S.
Client subjected to a traffic stop in the early morning hours on a residential street. He smells of alcohol and has a large stain on his shirt which he can't explain. A police check shows that he is also on a recent probation order. He is unable to explain either where he's been or where he's going and during the course of the roadside investigation his behavior and demeanor rapidly deteriorates. He registers a fail on a roadside breath device and is taken to the station where his behavior is so bizarre that after the breath tests that he is taken to a local hospital to be assessed for a drug overdose. Charged with impaired driving, over 80 and fail to comply with probation.
All charges dismissed. Over 80 withdrawn prior to trial because of defence refusal to adjourn trial to accommodate Crown’s expert witness who was needed because the breath tests had been taken more than two hours after the time of driving. The fail to comply was withdrawn on the first day of trial because the defence objected to the admissibility of photocopied court records offered in support of proving the terms and fact of the probation. Lastly, the impaired driving charge failed because the case, which had been scheduled for a full day, started late due to the Crown’s prioritization of other cases and then, when it couldn’t be finished that day, couldn’t be rescheduled to continue for another six months.  Defence application to stay for unreasonable delay accordingly granted on that return date.

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