Proving a person is impaired by a drug while driving may not be as hard as you think.

impaired by drug

The information provided in this article is very basic legal information on the topic of driving while impaired by drug. This is not legal advice and cannot be relied in defending any criminal charges.  The law of impaired driving is exceptionally complicated with significant consequences if you are convicted.  Please speak to an experienced criminal lawyer immediately if you are in need of legal assistance.  This article is written for general and informative purposes only.  This information cannot take the place of specific legal advice to any given situation.

It’s well known that obtaining a conviction for a person impaired by drug has it’s challenges for any prosecutor.  However, Canadian law is quickly adapting to these difficulties.  As a result, more and more impaired by drug cases are coming before the Courts.  In many instances, these prosecutions result in criminal convictions.  Convictions for impaired by drug charges carry with them the same penalties and ancillary consequences of impaired driving by alcohol – or as it is commonly referred to as “DUI”, “impaired driving” or “drinking and driving”.

The consequences of a conviction for impaired by drug include: a criminal record, astronomical insurance premium increases (if not complete ineligibility), fines, possible incarceration, mandatory incarceration for repeat offenders, and driving suspensions for a minimum of one year.  Needless to say, the stakes are high for anyone charged with this offence.

The basics of a criminal prosecution for impaired by drug cases:

impaired by drug charges marijuanaMany people wonder, how could the Court possibility conclude, beyond a reasonable doubt, that a person is impaired by drug?  Unlike alcohol, drugs do not produce the same sort of obvious and easily measurable effects on a person’s consumption.  Even if consumption of a drug is proven, it is equally difficult to determine if a person is impaired by that drug.

It’s important to keep in mind that under drinking and driving law there are two offences in the Criminal Code of Canada: 1) being impaired by alcohol while operating a motor vehicle, and 2) having a blood alcohol level over 80 milligrams of alcohol in 100 millilitres of blood.  This means that a Court might find a person was impaired by alcohol even if there is no measurement of a person’s excessive blood alcohol level.  Conversely, a Court could also conclude that a person has excessive blood alcohol levels even though they are not impaired.  Technically, a person charged with “impaired” and “over 80” can be convicted of both (or either) offences; they are mutually exclusive.

However, the offence of operating a motor vehicle while impaired by drug is a little bit different despite the procedural similarities in attempting to obtain a conviction.  In particular, the Crown prosecutor must prove that the accused was 1) in care and control of a motor vehicle, and 2) that their driving was impaired, and 3) that impairment was a result of drug consumption (and not fatigue or distraction for example).

There are many ways that a Crown Attorney prosecutor might do this.  This proof might be as simple as an admission of the accused: “Sorry for crashing the car officer, I am really high on cocaine and I couldn’t concentrate while driving.” or, it might be much more complicated and involving expert opinion evidence of whether the person was impaired by drug at the time of being in care and control of the motor vehicle.  This article intends to focus on the latter since you don’t need a lawyer to explain to you why admitting impairment by drug while operating a motor vehicle would result in a conviction (that’s why we always advise people to not make a statement to police!)

Reasonable suspicion of drug consumption in the preceding three hours of operating a motor vehicle

The Criminal Code of Canada provides that where a police officer has “reasonable grounds to suspect” a person has alcohol or drugs in their body, and has operated a motor vehicle within the previous three hours, they may make a demand for the suspect to a) provide a sample of breath (drinking), or b) participate in sobriety testing, or c) both.

As it relates to drugs, an officer’s might gain this reasonable suspicion by

  • smelling marijuana emanating from the person,
  • observing erratic driving behaviour,
  • obtaining an admission of the suspect of recent drug consumption
  • observing strange behaviour
  • observing bloodshot eyes, slurred speech, etc.

The process of screening for recent consumption of a drug.

Once that officer has reasonable suspicion that a person has drugs in their system, they may move to the next step which is often referred to as “roadside screening”.  This is not to be confused with a breathalyzer or more extensive sobriety testing that is typically done at the police station.  Roadside screening is simply to provide enough grounds to allow the officer to legally take the next step in the process in attempting to establish impairment of the driver.

In the case of alcohol, it is a small device one blows into at the side of the road (an “approved screening device” or “ASD”).  In the case of drugs, this screening is done through “Standard Field Sobriety Testing” (SFST).  SFST consists of several tests relating to coordination, concentration, and observations of the police officer.  This may include walking in a straight line and turning, standing on one leg, and eye movement tracking (“horizontal gaze nystagmus”).

Before an officer may arrest a person for operating a motor vehicle while impaired, they must have “reasonable grounds to believe” that the suspect is impaired by drug (or alcohol).  Therefore, failing the SFST may be used to then bolster the suspicions that an officer may hold in relation to a person’s impairment while operating a motor vehicle.  Failure of SFST will invariable lead an officer to the conclusion they now have “reasonable grounds” to arrest that person.  Once arrested, that person is taken as soon as practicable for evaluation by a qualified evaluator, i.e., a “Drug Recognition Evaluator” or “DRE”.

The process of evaluating impairment by drug.

The Criminal Code of Canada states that once reasonable grounds are established that a person is driving while impaired by drug (or previous 3 hours), the arresting officer may then take that person to an “evaluating officer” who is capable of conducting further, more elaborate testing in relation to impairment.

The testing done by an evaluating officer, often referred to as a “Drug Recognition Evaluator”, consists of:

  • a preliminary examination involving pupil measurement and comparison, pulse, eye tracking of an object;
  • a horizontal and vertical “gaze nystagmus test”,
  • a “lack-of-convergence” test;
  • divided-attention tests, which consist of balancing, walking and turning, one legged standing test, finger to nose test
  • blood pressure, temperature and pulse;
  •  an examination of pupil sizes under light levels of ambient light, near total darkness and direct light and an examination of the nasal and oral cavities;
  • an examination, which consists of checking the muscle tone and pulse; and,
  • a visual examination of the arms, neck and, if exposed, the legs for evidence of injection sites.

Based upon the performance of this testing, that “DRE” officer may then have reasonable grounds to believe that the person is impaired by drug.  If so, that DRE may then demand a sample of oral fluid, urine, or blood depending on the circumstances.  That sample is then sent for analysis to determine whether or not a “drug” was in the system of the suspect.

Without getting into the overwhelming complexities of why, this type of DRE evidence  is highly contentious under the present state of the law.  To date, there has been little meaningful challenges to the value such evidence provides in Canada.  However, many are of the view that this is a form of “junk science” that cannot predict with any degree of accuracy the impairment of an individual.  Suffice to say, that this is still a very active area of law that will undoubtedly be subjected to litigation by lawyers with expertise in impaired driving law.  There is also considerable debate in case law as to whether or not this evidence may be used to prove impairment, or simply to establish reasonable and probable grounds to obtain a sample of bodily fluids for analysis.  Only time will tell.

The process of proving impairment by drug.

As mentioned above, the proving of impairment beyond may be a very straightforward issue depending on the facts of the case.  If a person admits to being impaired by drug at the time of driving a motor vehicle,  there really is no further proof required if that confession is admitted into evidence and accepted by the Court.  Alas, if life were only so easy for prosecutors.

Most of the time, proving impairment by drug is a matter of collecting circumstantial evidence through a variety of sources.  Some of those sources may be the product of lay person or police evidence, and some of it may take the form of expert evidence.

Non-expert evidence may include:

  • Observations of witnesses or police officers who noticed erratic behaviour and/or driving;
  • The smell of drugs on a person on in close proximity;
  • Observations of consuming what appears to be drugs in the pertinent time periods;
  • etc.

Note that since impairment is something most people are familiar with in their day to day lives, lay people (and non-expert police officers) are permitted to offer their own opinions on whether a person was “impaired” as they saw it.  (R. v. Graat, SCC).  However, this may have limited weight at they are not experts who can offer more reliability in determining such an issue.

Expert evidence may include:

  • The report of a Drug Recognition Expert (although, as mentioned above, this is contentious as it is unclear if this is “expert evidence” or only evidence used for the purpose of grounds in obtaining further evidence);
  • A toxicologist;
  • Etc.

The expert evidence is typically introduced through the use of a toxicologist or a report from that expert.  That report would likely indicate what drugs were found in the suspect’s body at the time of the testing.  It would also include what, if any, such drugs might have on a person’s ability to operate a motor vehicle while the drugs were active.  If that impairment coincided with the time the person was operating a motor vehicle, then they may be convicted of the offence(s) charged.

Every piece of evidence serves it purpose in the prosecution of the case.  Ultimately, the Crown prosecutor would ask the Court to consider all relevant and admissible evidence to determine whether or not they have proven that the accused was impaired by drug while (or <3 hours) operating a motor vehicle.  The Crown must convince the Court beyond a reasonable doubt of all essential elements of the offence before any person may be convicted.

Conclusion: A recap on how an impaired by drug case is investigated and prosecuted successfully:

  1. Reasonable suspicion by a police officer of drug in the body of the suspect who has operated a motor vehicle in the past three hours.
  2. Screening (SFST)
  3. Reasonable grounds that a person is impaired by drug
  4. Suspect taken for DRE evaluation
  5. DRE conclusion leads to demand for bodily sample
  6. Bodily sample analyses by toxicologist
  7. Toxicologist provides report that corroborates drug was in the body of suspect and the effects that this drug may have had upon them at the time of driving
  8. Judge can also take into account other observations made by police and witnesses in assessing impairment

Sean Robichaud, Barrister & Solicitor
Call (416) 999-8389 if you have any questions about cases like this or if you are in need of legal assistance.