Drug-Impaired Driving: Legal Challenges on the Road to Traffic Safety

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Drug-Impaired Driving: Legal Challenges

on the Road to Traffic Safety


Tuesday, October 21, 2014 2:15 pm-3:00 pm

R. Solomon

Professor, Faculty of Law




Driving under the influence of a narcotic was first prohibited in

1925. The prohibition was reworded in 1951 in terms of driving while one’s ability to do so was impaired by alcohol or a drug.


However, police had no specific authority to gather evidence of

drug-impaired driving until 2008.


There are no data on the number of drug-impaired driving charges

prior to 2008, because they were not separately recorded. It appear that few charges were laid, even after the sharp rise in recreational drug use in the mid-1960s.


Prior to the 2008 drug-impaired driving amendments, prosecuting

drug-impaired driving cases was onerous and the outcome was uncertain.


While there were successful prosecutions prior to 2008, they were

limited to obvious cases.



For example, in R. v. Rosskoph, the accused was speeding, hit the curb 3 times, veered into the adjoining lane 4 times, stopped 10 feet before a stop sign, and turned without signalling. His face was flushed, his speech and movements were slow, he was unsteady on his feet, fumbled with and dropped his wallet, and had difficulty picking it up. When asked if he had been drinking, the accused replied: “No, I don’t drink. It’s the codeine.” He later explained: “I’ve been chewing Tylenol with codeine all day cuz my teeth are all f ’ed up. I know I shouldn’t have been driving.”


Even in this case, the judge stated that: “the preferred practice [is]

for the Crown to call expert medical or scientific evidence regarding the effects of drugs. … the court cannot take judicial notice of the effects of various drugs.”


Thus, even when a driver had consumed drugs and was obviously

impaired, the Crown was advised to adduce expert evidence to prove that the drug was the cause of the driver’s impairment.


The 2008 Drug-Impaired Driving Amendments



The amendments authorize the police to demand a standardized

field sobriety test (SFST) from a driver whom they have reasonable grounds to suspect has any drugs (and/or alcohol) in his or her body.


If the accused fails the SFST and alcohol has been ruled out, the

police will have reasonable grounds to believe that he or she has committed the offence of driving while impaired by drugs.


The police may then demand that the driver submit to a drug

recognition evaluation (DRE), which consists of two components: •  The first component involves 11 separate steps, namely 10 sets

of physiological, balance, and divided attention tests, plus the evaluating officer’s written opinion on whether the suspect’s ability to drive is impaired by a drug and, if so, by what category of drugs.

If the officer concludes that the suspect’s ability to drive was impaired by a drug, he or she may demand that the suspect provide a sample of blood, urine or saliva.


•  The second component is the analysis of the suspect’s sample.

Charges will only proceed if the sample tests positive for the presence of the drug category identified in the officer’s report.


A failure/refusal to take a SFST or DRE, without a reasonable

excuse, constitutes a federal offence which carries the same penalties as driving while one’s ability is impaired by a drug.


The SFST and DRE process is exceedingly technical, takes about

two hours, and involves the collection of over 100 separate pieces of information.


A DRE can only be conducted by an “evaluating” officer. To

qualify for this designation an officer must be accredited and certified by the International Association of Chiefs of Police. Training costs per evaluating officer are high ($17,000), as are the costs of maintaining certification.


Among other things, evaluating officers are required to maintain a

“rolling” log of all evaluations they have conducted as well as a current resume.


Legal Concerns



Defence counsel may demand production of the evaluating officer’s

certification, recertification, “rolling log,” resume documents, and other data.


The basis of an officer’s demand for the SFST may be challenged,

particularly if the driver did not exhibit obvious signs of drug use. If the Crown cannot prove that the officer had reasonable grounds to suspect the driver had drugs in his or her body, the subsequent evidence will most likely be excluded.


The accuracy of SFSTs and DREs are frequently challenged.

•  Research indicates that SFSTs significantly over predict impairment by cannabis and other drugs, as measured by performance on driving simulators.

•  DREs largely focus on drug presence, not driving impairment. It is only the four divided attention and balance tests of DRE that directly assess skills thought to be important in driving.


•  Two of the four tests used in the DRE (the walk-and-turn and

one-leg-stand tests) repeat components of the SFST which, as indicated, over predicts impairment.

•  The other two tests in the DRE (the Romberg balance and

finger-to-nose tests) were not included in the original SFST battery of tests because they were not as accurate as the walk-and- turn and the one-leg-stand tests.


The SFSTs’ high false positive rate may be acceptable if SFSTs are

used solely for screening purposes.


However, relying on the DRE’s four divided attention and balance

tests in a criminal trial is problematic because the Crown must prove beyond a reasonable doubt that the accused’s ability to drive was impaired by a drug when arrested.



Some courts have rejected the DRE evidence out of hand, because it is not sufficiently reliable. Other courts have permitted evaluating officers to testify on the DRE procedures, but have prohibited them from testifying as to whether the accused’s ability to drive was impaired by a drug.


Even if all of the evaluating officer’s testimony is ruled to be

admissible, the court may simply not be convinced beyond a reasonable doubt that the accused’s driving ability was impaired by a drug when arrested.


Unlike breath test results, there are no statutory presumptions of

accuracy or temporality regarding the results of a DRE.


In R. v. Perillat, the accused admitted to smoking marijuana 2½

hours earlier and failed the SFST. Based on the physical and behavioural elements of the DRE, Constable Schaefer concluded that the accused’s driving ability was impaired by cannabis and the presence of the drug was confirmed by a urine test.




Nevertheless, the judge in Perillat stated:

[A]t its best, Constable Schaefer’s evidence convinces me that the accused had used marijuana at some point prior to her being stopped at the police check stop that evening and that she still had some of it in her system at the time he did his Drug Recognition Evaluation on her at the police station. What his evidence does not convince me of is that at the time she was driving, her ability to operate a motor vehicle was impaired by marijuana.

In dismissing the charge, the judge stressed the lack of any evidence that the accused had been driving in an erratic, impaired or improper manner.


Perillat and similar cases do not bode well for drug-impaired

driving enforcement. The courts have required detailed expert evidence on the 12 steps of the DRE, the qualifications of the evaluating officer and the relationship between the drug in issue and the accused’s ability to drive at the time of the arrest.



Despite the sharp increases in driving after drug use, the number of drug-impaired driving charges remains extremely low. In 2013, there were only 1,181 drug-impaired driving charges (2.19% of total impaired driving charges).


There are no Canadian conviction data for drug-impaired driving, but

it is likely that only the most obvious cases result in a charge and a conviction.


Charge statistics and drug survey data indicate that a person would

have to drive after using cannabis once a day for almost 40 years before being charged once, let alone convicted.


The processing of drug-impaired driving suspects is complex,

technically exacting, time-consuming, and readily susceptible to legal challenge.


The current federal drug-impaired driving law is unworkable and

more effective enforcement measures are required.




Several Western European and Australian jurisdictions have enacted drug-impaired driving laws based on per se limits and mandatory roadside saliva tests followed by more sensitive evidentiary tests, if warranted.


With modifications to comply with the Canadian Charter of Rights

and Freedoms, this approach may serve as a useful model for

developing a more effective system of drug-impaired driving enforcement in Canada, especially for the most commonly used illicit drugs.


The initial per se drug limits may need to be set at relatively high

thresholds and introduced incrementally, in keeping with advances in drug-impaired driving research and the cost and accuracy of oral fluid testing.


Although reliance on SFSTs and DREs will need to continue in

regard to some drugs, it should wane over time as drug testing technology improves.





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