On Wednesday, Ontario’s new government announced a change in policy for cannabis use, indicating that they will allow it to be used anywhere where tobacco is smoked when it is legalized on Oct. 17, 2018, and not restricted to residential homes as previously planned. This move would align the province’s policy with the Smoke-Free Ontario Act, with the Alcohol and Gaming Commission of Ontario (AGCO) set up as the proposed regulator to issue private store licences.
One of the ancillary effects of this is that residents in the province will invariably be consuming cannabis outside of the home, and if not using public transit or other means of transportation, may be found behind the wheel. While this does pose a potential public health and safety risk, governments across Canada are still struggling with how to properly deal with this issue, despite the passing of Bill C-46 in June of this year.
On Aug. 27, 2018, the federal government approved use of a device for saliva screening of roadside testing of marijuana, with $161 million pledged over 5 years for police training and acquiring the equipment. Pursuant to paragraph 254.01(b) of the Criminal Code, the annexed Approved Drug Screening Equipment Order states,
1 A Dräger DrugTest® 5000 and a Dräger DrugTest® 5000 STK-CA, when used together, are approved for the purposes of section 254 of the Criminal Code as equipment that is designed to ascertain the presence of a drug in a person’s body.
The accompanying Regulatory Impact Analysis Statement reads as follows:
An Act to amend the Criminal Code (offences relating to conveyances) and to make consequential amendments to other Acts (the Act) authorizes peace officers to use “approved drug screening equipment” when they suspect a driver has drugs in their body. The Act authorizes the Attorney General of Canada to approve this equipment by ministerial order. The inclusion of approved drug screening equipment in the Approved Drug Screening Equipment Order (the Order) is necessary so that peace officers may use approved drug screening equipment at the roadside to test drivers for the presence of one or more drugs.
The Attorney General of Canada has approved the drug screening equipment known as the Dräger DrugTest® 5000 STK-CA and the Dräger DrugTest® 5000, when used together, as “approved drug screening equipment” for the purposes of the Criminal Code. The Dräger DrugTest® 5000 STK-CA is the oral fluid collection system, and the Dräger DrugTest® 5000 is the reader. This drug screening equipment has been uniquely configured to Canadian evaluation standards.
Despite this rigorous testing, several municipalities have already declined to use the device, or intend to wait and see before purchasing. Concerns over its calibration and use in cold weather in particular have been highlighted by law enforcement. The company indicates that if the devices are kept inside police vehicles, they are unlikely to be exposed to temperatures under 4 degrees, where some problems have been identified in its use.
Heuestis et al. found that this device demonstrated a lower cutoff for occasional compared to chronic users of cannabis, with up to 11% higher sensitivity for chronic users. The median detection times ranged from 12 hours for occasional users to 21 hours for frequent users. Sensitive and specific results were available for the 6-8 hour time frame, allowing for roadside testing of the presence of marijuana.
At lower levels of instrument calibration, the sensitivity for the presence of marijuana is lower but the specificity is higher, and at higher levels the sensitivity is higher but the specificity is lower. Joseph Hall of the Toronto Star interviewed Andrew Murie of MADD Canada about what this might mean,
“For example, if it was set at five nanograms for THC, there might be a case where the reliability (of the devices) drops from maybe 98 per cent to 91,” he says. “So if you set it really high, you get the most impaired people.… Anyone who says they smoked yesterday, there’s not a chance in a million years they’re going to fail one of those tests.”
The roadside spit kits will simply deliver a pass or fail verdict. A failure will prompt further screens, likely in the form of a blood test at a nearby police station or clinic.
It’s here that the legal ramifications come into play, with a 2 nanogram THC reading in the blood prompting a summary conviction and five nanograms representing a criminal offence — with punishments in line with those for alcohol.
Beirness & Smith examined these devices for use in the enforcement of drug-impaired driving in Canada, and were able to obtain results within 10-15 minutes. False positives for all drugs ranged from 3-7%, and although the positive predictive value for THC was 92.2%, the false alarm rate was 4.5%.
Gjerde et al. specifically looked at the devices to be used in Canada through field testing by the Norwegian Mobile Police Service (NMPS). Although law enforcement highlighted it as a useful tool, the authors concluded,
The DDT5000 did not absolutely correctly identify DUID offenders due to fairly large proportions of false-positive or false-negative results compared to drug concentrations in blood.
Law enforcement in Australia have also noted difficulties in using the machine, with difficulties picking up on positive readings for higher levels.
The test also does not measure any function of impairment as a result of cannabis, and there are other potentially impairing substances that are not detected well by these devices. Impairment of a driver may be due to use of benzodiazepines, cathinones, or dissociative anesthetics, and are not identified through this testing. Young drivers are expected to have no presence of marijuana at all in many jurisdictions, which may have no connection at all to recent use or effects on the body.
The National Highway Traffic Safety Administration publication, “Drugs and Human Performance Fact Sheets,” states,
It is difficult to establish a relationship between a person’s THC blood or plasma concentration and performance impairing effects. Concentrations of parent drug and metabolite are very dependent on pattern of use as well as dose.
…Significant THC concentrations (7 to 18 ng/mL) are noted following even a single
puff or hit of a marijuana cigarette…
It is inadvisable to try and predict effects based on blood THC concentrations
alone… It is possible for a person to be affected by marijuana use with concentrations of THC in their blood below the limit of detection of the method.
Sarah Leamon, a lawyer in Vancouver, explained to the Georgia Straight how cannabis is highly individualistic and affects each person differently,
Under the Criminal Code, 80 milligrams of alcohol per 100 millilitres of blood, or 0.08 percent, is considered legal intoxication. Leamon said that, barring a few variables like weight, this is accurate for most alcohol consumers but the same approach cannot be applied when it comes to cannabinoids.
“THC is stored in fat cells long after the effects have worn off. It is not metabolized through the body in a consistent rate and there really is no formula for us to determine how it moves through every human body,” she said
The use of saliva tests is just one tool for screening, which is likely to be used in conjunction with a Drug Recognition Expert (DRE) employing a Drug Influence Evaluation (DIE). The RCMP website describes the DIE process as follows:
- Breath test to rule out alcohol as the primary cause of impairment
- Interview of the arresting officer
- Preliminary examination (includes the first of three pulse checks)
- Eye examinations (Horizontal Gaze Nystagmus, Vertical Gaze Nystagmus and the ability of the eyes to converge)
- Divided attention tests (SFSTs plus finger to nose and Modified Romberg balance test)
- Clinical indicators examinations (blood pressure, temperature, second pulse)
- Darkroom examination of pupil sizes (also includes examination of nasal and oral cavities)
- Muscle tone examinations
- Search for and examination of injection sites
- Statements and interview of the suspect
- Opinion of the DRE
Based on the totality of the evaluation, the DRE forms an opinion as to whether or not the subject is impaired. If the DRE determines that the subject is impaired, the DRE will indicate what category or categories of drugs may have contributed to the subject’s impairment. The DRE bases these conclusions on his training and experience and the DRE Drug Symptomatology Matrix. While DREs use the drug matrix, they also rely heavily on their general training and experience.
- Toxicological sample (urine and oral fluid or blood)
After the evaluation, the toxicological sample is sent to a forensic laboratory for analyses to confirm or refute the findings of the evaluator. The mere presence of a drug in the sample does not constitute sufficient evidence to charge a person as being impaired by a drug. The evaluation must show impairment, signs and symptoms consistent with one or more drug categories, and the evaluator’s findings must be supported by the toxicology.
The DRE protocol is itself subject to much scrutiny, with Rubenzer questioning its validity. Although several American courts have admitted DRE evidence and testimony, there are some cases that have highlighted some concerns over its use.
In R. v. Bingley, Chief Justice McLachlin allowed the admissibility of DRE evidence, on the basis of the Evaluation of Impaired Operation (Drugs and Alcohol) Regulations. She stated,
 That Parliament has established the reliability of the 12-step drug evaluation by statute does not hinder the trier of fact’s ability to critically assess a DRE’s conclusion of impairment or an accused person’s right to test that evidence. Cross-examination of the DRE may undermine his or her conclusion. Evidence of bias may raise doubt about the officer’s conclusion. The officer may fail to conduct the drug recognition evaluation in accordance with his or her training. A DRE may draw questionable inferences from his or her observations. Bodily sample evidence obtained under s. 254(3.4) may refute the DRE’s assessment, as may evidence of bystanders or other experts. It will always be for the trier of fact to determine what weight to give a DRE’s opinion. Any weight given to a DRE’s evidence will necessarily respect the scope of the DRE’s expertise and the fact that it is not conclusive of impairment.
 The trial judge correctly found that the DRE in this case was an expert for purposes of administering the 12-step evaluation and determining whether Mr. Bingley was driving while impaired for the purpose of requiring further testing. He erred, however, in concluding that because the officer was not an expert in the scientific foundation of the various elements of the test, none of his opinion evidence was admissible. The DRE’s expertise is not in the scientific foundation of the test but in the administration of the test itself. As the other criteria for admissibility are not in issue, Constable Jellinek’s opinion evidence should have been admitted.
However, Justice Karakatsanis’ dissent stated,
 Given the unsettled nature of the case law and the relatively recent reception of DRE evidence into Canadian courts, it was open to the trial judge to treat the proposed testimony as an opinion based on novel science. Although he recognized the DRE’s special expertise in administering the 12-step evaluation for the purpose of requesting a bodily sample (i.e., advancing the police investigation), the trial judge found the DRE lacked the necessary qualifications to offer an opinion on impairment in court. The trial judge’s reasons indicate that neither threshold reliability nor the adequacy of the officer’s qualifications were conceded.
 As the DRE was not himself trained on the reliability of the 12-step evaluation, the Crown could have called a different expert for this purpose. As it did not, there was a lack of evidence about the reliability of the regime. The trial judge was therefore entitled to exclude the DRE’s opinion on the results of his evaluation.
…officers were able to detect impairment and identify impairment associated with the class of drugs administered with a modest degree of accuracy (43% to 62%).
On Sept. 25, 2017, the American Civil Liberties Union of Georgia filed a suit against Cobb Count Police Department for their arrest and detainment of three individuals based on the use of a DRE, though blood tests confirmed the absence of marijuana in their blood. The complaint to the United States District Court for the Northern District of Georgia – Atlanta Division, states,
None of the Plaintiffs were under the influence of marijuana, and all tested negative for any cannabinoid metabolites. Nevertheless, the Plaintiffs were arrested and charged with driving under the influence of drugs. Ultimately, all driving under the influence charges against all Plaintiffs were dropped.
The Canadian Bar Association identifies a number of other constitutional challenges that could be raised against Bill C-46, including the mandatory alcohol screening in s. 320.27(2). Although this remains the first step of a DIE, placing this into law means that law enforcement can now ask for an breath test without any probable cause.
The legalization of marijuana was expected to be a legislative shift towards a permissive culture, the approach undertaken and the potential risks to the public mean that we will invariably have considerable litigation around the use and techniques of cannabis testing in the near future.