Proposed federal legislation on cannabis and alcohol impaired driving

Introducing our new “Cannabis and Driving” blog series.

Impaired driving in Canada refers to the operation of a motor vehicle while the driver’s ability is impaired by alcohol or drugs. In this series, I look at existing and proposed laws concerning impaired driving by cannabis and compare these laws with those for alcohol. In doing so, I contrast the research that supports or refutes these laws. A critical element for assessing the value of these laws is the criteria used to define impairment. In this series, we see that the nature of the scientific evidence used for assessing alcohol impaired driving differs substantially from cannabis impaired driving.

What are current federal laws for cannabis and alcohol while driving?

Today in Canada, convictions for impaired driving by cannabis are based on behavioural grounds of drug impairment, using the Drug Recognition Expert (DRE) approach. This approach typically involves obtaining behavioural evidence of drug impairment, such as poor balance or difficulty concentrating, followed by drug tests, often urinalysis, to confirm drugs have indeed been used. As epidemiologist Leon Gordis writes in Chapter 5 of Epidemiology, the advantage of this two-step approach is that those identified as impaired are more likely to be impaired than with a simpler one-step approach. The drawback is that the process is cumbersome and dependent on police correctly identifying drivers that appear under the influence, a difficult task; hence, it results in a low conviction rate. In 2016, drug-related driving charges, including those for cannabis, accounted for about 3.9% of all charges, with the remainder (97.1%) being alcohol.

For alcohol, it is a criminal offence to drive with a blood alcohol concentration (BAC) of 0.08% alcohol (this legislation, frequently referred to as per se law for the Latin term meaning “by itself” came into effect in 1969). It is also a criminal offence to refuse a sobriety test assessment or a breath test. The original per se law was based on a breathalyzer reading at a police station. Prototypes of breath tests for alcohol were designed in the 1800s, but only through refinements in designs has the roadside breath test that we have today been approved as an accurate estimation of a person’s actual BAC (as proven by comparisons with blood tests). However, under current laws, police are still required to have reasonable grounds to order a driver to provide a breath sample.

What are provincial laws for alcohol or cannabis while driving?

In addition to the criminal laws proposed by the federal government, many have additional laws against drinking and driving. Most provinces have penalties for drivers at BAC levels of 0.05% alcohol – the equivalent of about 2 standard drinks for a 160-pound man. Ignition interlock systems that prevent drinking drivers from starting a vehicle until passing a breathalyzer test, administrative license suspensions, and vehicle impoundment are other types of laws and consequences for drinking drivers. For cannabis, Alberta has passed zero tolerance laws against any amount of cannabis detected in new drivers. BC is considering similar legislation plus a 90-day Administrative suspension when police reasonably believe drivers are affected by cannabis.

What is the proposed federal legislation for cannabis and alcohol while driving?

The Government of Canada prepared a backgrounder report in 2017 that describes proposed legislative changes for laws in relation to cannabis and driving. The legislation would permit roadside oral fluid tests when law enforcement officers reasonably suspect that a driver has taken cannabis or other drugs.  For positive readings, officers could demand a drug evaluation or a blood sample. A blood test reading of 2 to 5 ng/ml THC in whole blood would be subject to a summary (i.e., less serious) criminal conviction and a penalty fine of up to $1,000.  A reading over 5 ng/ml could be subject to an indictable (i.e., more serious) offence and a mandatory fine of $1,000 for a first offence and higher penalties for repeat offenders. Those with both a BAC over .05% alcohol and 2.5 ng/ml THC could also be charged with an indictable offence.

New laws targeting drinking drivers are also on the table. Proposed changes would let law enforcement officers randomly administer an alcohol breathalyzer test to a driver without any suspicion the driver has been drinking. The laws propose escalating mandatory minimum fines based on different BAC thresholds and repeat offenders would be subject to mandatory prison sentences, similar to the current ones.

What is the scientific basis for the proposed laws? 

The Government of Canada did not provide references of scientific studies in its 2017 backgrounder to support these recommendations. In this blog series, I will review scientific studies to see what the evidence says about cannabis impairment in an attempt to understand why the Canadian government is proposing these changes to impaired-driving laws, and whether the proposed legislation makes sense within Canadian criminal laws. In doing so, comparisons will be drawn with alcohol.

Part 2: The safety benefits of alcohol breath-testing: a research summary

Part 3:  The safety benefits of THC blood testing: a research summary

Part 4: The myth and origins of 24-hour performance deficits from cannabis

Scott Macdonald is the Assistant Director of research at the Canadian Institute for Substance Use Research and a professor in the School of Health Information Science at the University of Victoria. He has been an expert witness in several cases related to drug testing in the workplace. Material from this series is taken from his book, Cannabis Crashes: Myths and Truths, Lulu Press. 

**Please note that the material presented here does not necessarily imply endorsement or agreement by individuals at the Canadian Institute for Substance Use Research.

Drinking, Disease and Distance: Access and use of primary health care services for treatment of alcohol-attributed diseases in rural BC

Since the turn of the century, there has been a sharp decrease in the proportion of the population that resides in rural and remote British Columbia (BC) communities. In 2011, 86% of British Columbians (3,790,694) lived in urban areas, whereas only 14% of the population, or 609,363 persons, resided in rural communities. Although a much smaller proportion of the population lives in rural areas, these communities have disproportionately higher rates of alcohol consumption and alcohol-related hospitalizations than urban areas of BC, such as Vancouver and Richmond. These higher rates of alcohol-related harms, when combined with poor access to health care, can result in greater disease severity and increased rates of alcohol-related deaths. Although these challenges have existed for many decades, we still have an incomplete understanding of the barriers to obtaining addictions treatment services, which is important information that could be used to inform health care policy and resource allocation decisions throughout the province.

For the past two years, I have worked with my former PhD Supervisor, Dr. Scott Macdonald, to address this lack of knowledge by examining access and use of primary health care services by persons with alcohol-attributed diseases in rural BC. I focused on primary health care physicians because they are the most accessible type of health care provider available in rural and remote communities that often do not have hospital-based substance use treatment services. Family doctors are ‘gatekeepers’ to specialist services, and have a significant role to play in the identification and treatment of alcohol-attributed diseases early in their development.

For these projects, I studied both geographic (spatial) variations in primary health care use, as well as place-based physician experiences treating persons in rural communities. In the first project, I used physician-billing data to model use of general practitioner services by persons with alcohol-attributed diseases from 2001-2011 with administrative health data provided by Population Data BC. We were surprised to learn that from 2001-2011, cases of alcohol-attributed diseases in primary health care practices grew significantly (53.3%), from 14,882 cases in 2001 to 22,823 cases in 2011.1 We also found geographic inequities in alcohol-attributed disease cases among primary health care populations by Health Service Delivery Area (HSDA). Rural areas generally had much higher rates of alcohol-attributed disease cases than highly populated areas of the province. For example, in the Northwest HSDA (which includes Smithers, Prince Rupert, and Kitimat) cases rose 77.2% from 57.1 per 10,000 in 2001 to 101.3 per 10,000 in 2011. The 2011 rate of alcohol-attributed disease cases per 10,000 in the Northwest HSDA was the highest in the province – almost double the provincial average of 48.2 cases per 10,000. In comparison, several urban areas such as Vancouver, Richmond, and Fraser North had no significant increases in alcohol-attributed disease cases during this same period.

In the second study, I distributed a mail and online survey to general practitioners in rural areas that were defined using the Rural Coordination Centre of BC’s system for defining rural communities. We received responses from 22% of participants (for a total of 67 completed surveys) who overwhelming reported that they experienced significant challenges in referring their patients to treatment in urban areas. Physicians cited long waitlists and a lack of residential treatment facilities and inpatient services as the main challenges to referring patients. In many of the surveys, physicians wrote about personal experiences working in their community, and the challenges associated with delivering appropriate health care in isolated communities. They also stated that travel costs, distance to treatment facilities, and responsibilities in their hometowns prevented patients from obtaining required services only available in other communities. Even when services were acquired outside of the community, many physicians reported difficulties upon returning home and; as one physician summarized: “relapse on return [to community] from treatment is the rule rather than exception. We want local treatment [Family Physician, #038].”2

The outcomes of our research suggest that an increasing number of British Columbians are presenting with alcohol-attributed diseases to general practitioners, and there are large geographic inequities in the incidence of alcohol-attributed diseases in primary health care patients. We also found that rural family doctors frequently experience significant challenges when referring patients to treatment. Addressing these challenges requires that we work with residents and health professionals in rural places to develop innovative – and cost effective – methods for enhancing the continuum of services provided to rural residents. In this study, several physicians suggested having a centralized referral phone number for substance use treatment services in urban Vancouver, Victoria, and Nanaimo, which would not require a large public sector investment. Additional participatory research, and accompanying policy development processes, is required to articulate and implement these suggestions for service improvement in rural areas where populations disproportionately experience alcohol-related harms and related diseases.


1 Slaunwhite, AK., Macdonald, S. (2015). Primary health care utilization for alcohol-attributed diseases in British Columbia, Canada 2001-2011. BMC Family Practice. (in press).

2 Slaunwhite, AK., Macdonald, S. (2015). Alcohol, Isolation, and Access to Treatment: Family Physician Experiences of Alcohol Consumption and Access to Health Care in Rural British Columbia. Journal of Rural Health. (in press).

A photo of Amanda Slaunwhite

Author: Amanda K Slaunwhite, Collaborating Scientist, Centre for Addictions Research of BC; Post-Doctoral Fellow,  University of New Brunswick.

*Please note that the material presented here does not necessarily imply endorsement or agreement by individuals at the Centre for Addictions Research of BC