Laws & Penalties

This module describes the various approaches to laws and legal penalties that are related to drug use as well as drug-impaired driving. It briefly highlights the various ways in which jurisdictions can use laws to prevent and reduce drug-impaired driving, and summarizes different legal strategies that are utilized in North American, European, and Australian jurisdictions. Examples of laws in some jurisdictions are shared and evaluations that investigate the effectiveness of these laws in reducing drug-impaired driving are examined.

The module also discusses the effectiveness of different types of penalties for alcohol- and drug-impaired driving offences, including criminal sanctions as well as administrative sanctions (e.g., jail, probation/parole supervision, licence suspensions and vehicle impoundment). The module also explores post-conviction sanctions (e.g., specialty courts and ignition interlock devices) to provide insight into strategies that may have potential to reduce impaired driving. Research evidence specific to drug-impaired driving is more limited as compared to research about alcohol-impaired driving.

  1. What different types of legal strategies can be used by governments to manage drug-use?
  2. What different types of laws can be used to manage drug-impaired driving?
  3. What criminal penalties are applied to convicted drug-impaired drivers?
  4. Apart from criminal penalties, are there other types of penalties that can be applied to convicted drug-impaired drivers by provinces or states?
  5. What are the current laws and penalties for drug-impaired driving in:
    Canada United States Europe Australia
  6. Have the different types of laws and penalties used to manage drug-impaired driving been evaluated, in terms of reducing the prevalence of drug-impaired driving and preventing repeat drug-impaired driving offences?
    1. Have behavioural impairment laws been evaluated, and if so, what is known about their effectiveness?
    2. Have per se laws been evaluated, and if so, what is known about their effectiveness?
    3. Have zero tolerance laws been evaluated, and if so, what is known about their effectiveness?
    4. Have prison and jail sentences as a penalty for impaired-driving been evaluated, and if so, what is nown about their effectiveness?
    5. Have probation/community supervision and parole sentences as a penalty for impaired-driving been evaluated, and if so, what is known about their effectiveness?
    6. Have licence suspensions for impaired-driving been evaluated, and if so, what is known about their effectiveness?
    7. Have vehicle impoundment programs for impaired-driving been evaluated, and if so, what is known about its effectiveness?

Post-Conviction Programs

  1. What are drug courts, and how are they applied to drug-impaired drivers?
  2. What are DWI (Driving While Impaired) Courts?
  3. Are drug-impaired drivers in the U.S. required to abstain from drug and alcohol use after conviction? How are they monitored or tested for drug and alcohol use post-conviction?
  4. What are remedial driver licencing programs and how are they applied to drug-impaired drivers?
  5. Could a device similar to an alcohol ignition interlock, which is used to monitor convicted alcohol-impaired drivers, ever be used for drug-impaired drivers?

Legislation and Penalties

1. What different types of legal strategies can be used by governments to manage drug-use?

Laws regarding the permissibility of illicit drug use in a particular jurisdiction can have an impact on drug-impaired driving laws. As such, a brief legislative overview of the legal approaches toward drug use that exist can provide important context to understand drug-impaired driving laws. It should be noted that the aims of this learning centre are to share information about the laws and regulations regarding drug-impaired driving and how it is managed in different jurisdictions. It is not to discuss or promote strategies on drug use or legalization. Instead, this legislative overview is provided only as context for the options available to jurisdictions regarding potential strategies to legislate and manage drug-impaired driving. Modern day drug use laws exist on a continuum from prohibition to legalization with government regulation. Each of these approaches is distinct and they are briefly described below.

  • Prohibition. Prohibition is based on the philosophy that illicit drug use is absolutely prohibited within a jurisdiction and is usually a matter of criminal law. Substantial penalties are often applied for drug offences, many of which include incarceration (jail or prison)1 and a criminal record for convicted offenders.
  • Decriminalization. Decriminalization strategies vary from jurisdiction to jurisdiction but are generally viewed as a half-measure between prohibition and legalization. Prohibition remains in effect but possession charges, particularly for small amounts of drugs deemed for personal use, may no longer be criminal offences. Instead they become civil violations or misdemeanour charges2, where no criminal record is established and the punishment is a small fine.
  • Legalization without government regulation. Legalization without government regulation occurs when drug use is completely legal with no sanctions or restrictions pertaining to sales, distribution, or use. Although the criminal consequences are removed for drug use, the lack of regulation can lead to a number of social problems such as: drug-impaired driving, underage drug use, chronic health and/or mental health problems associated with use, increases in emergency room admissions and lack of available safety prevention measures.
  • Legalization with government regulation. Legalization with government regulation gives jurisdictions the opportunity to control and regulate distribution, sales and access to drugs. Although drug use is technically legal it would be subject to certain restrictions, similar to alcohol or tobacco (e.g. place of sale, age of purchase, etc.), that would allow sanctions against recklessness.

Stohr, et al., 2020 conducted a three-year study of the effects of recreational marijuana legalization on law enforcement and crime. Their study included law enforcement professionals from a variety of state, urban, suburban, rural, and tribal agencies as well as the neighbouring state of Idaho. Utilizing case study profiles and assessing qualitative data (focus groups, interviews) and quantitative data (Uniform Crime Reporting Program, service call records, body-worn and dash-mounted camera footage) to determine how law enforcement practices and strategies and crime had been affected by marijuana legalization in Washington as well as how it had changed policing in adjacent state areas.

Overall, they found that marijuana legalization did not have any consistent positive or negative effects. Some of the predicted negative outcomes (by legalization opponents) were supported by the qualitative data and included increased concern with traffic safety issues, greater youth access to marijuana, and the persistence of illegal sales of marijuana. A positive outcome was that legalization appeared to coincide with an increase in crime clearance rates in several areas of offending. This could suggest that legalization may have created a net positive redistribution in police-human resource allocation and, thus, may have created the perception that law enforcement interactions with citizens had improved. An obvious result of legalization was a significant drop in the number of people arrested and processed for non-violent marijuana possession offences.3

1 There is an important distinction between jail and prison. Whereas jail is a short-term imprisonment (two years or less) at a local facility and is imposed for lesser offences, prison is imposed for longer-term incarnation (two years or more) in a provincial, state or federal facility following a conviction for more serious offences.
2 Misdemeanor offences are lessor category of criminal offences, but are less serious than felony offences and may be expunged after a certain amount of time.

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2. What different types of laws can be used to manage drug-impaired driving?

There are three main categories of laws that are currently used to address drug-impaired driving: behaviour impairment laws, per se laws and zero-tolerance laws.4

  • Behaviour impairment. Prosecution of offences related to behavioural impairment are based on the collection of evidence of physiological impairment by trained police officers, and toxicological test results. Impairment-based laws require police officers to document observed impaired behaviour that is directly linked to consumption of a specific drug. Evidence that is gathered may include observations of an officer while the vehicle is in motion and the driver during the stop (e.g., erratic driving, inability to locate licence/registration, stumbling out of the vehicle), driver performance on Standardized Field Sobriety Tests (SFSTs), a battery of tests by a trained Drug Recognition Expert (DRE), along with a confirmatory drug analysis test.
  • Per se. These laws make it a criminal offence to operate a vehicle with a concentration of a drug in the body above a specified legal threshold.5 Per se laws are thought to simplify the investigative and adjudication processes, since evidence of behavioural impairment may not be required. Instead, evidence from toxicological tests of bodily fluid(s) can be used to demonstrate that a driver was in excess of the legal threshold while in control of or operating a vehicle.6 However, “reasonable suspicion” and “probable cause” of impaired driving is often still required before a bodily fluid sample can be legally collected, with the exception of jurisdictions where roadside drug tests (RDT) are permitted.7Although per se laws are perceived to be more easily enforced, they are associated with greater costs (i.e., roadside testing devices, laboratory analysis), and are more vulnerable to challenge in court in relation to drugs. This is due to the lack of clear consensus regarding the threshold that should be set and whether there is clear and convincing evidence that a majority of people would be considered impaired and unable to safely operate a motor vehicle at this threshold.For example, per se blood alcohol concentration (BAC) limits for alcohol are based upon decades of experimental research that demonstrated a clear dose-response relationship between alcohol and driving impairment, and that all persons would be impaired and unable to safely operate a vehicle at this limit. This is not the case for drugs. Specifically, for many illegal and legal drugs, there is a lack of consensus about the specific threshold at which the drug impairs driving abilities for all drivers. This is because the impairing effects of many drugs may vary overtime.8 Additionally, the effect of different concentrations of a drug will vary across users depending on age, sex, frequency of use, metabolism/body fat, and presence of other impairing substances.9 The impairing effects of some drugs may also diminish over time and the presence of higher levels of a drug in the body may not be correlated with increased impairment. In summary, the dose-response relation of drugs on users is not uniform, and several factors may influence the impairing effects on individual users. Although there is research which suggests it may be possible to establish a per se limit, it is not comprehensive enough to base a scientifically supported legal limit and more research must be undertaken.10
  • Zero tolerance. These types of laws are a form of per se laws, wherein the limit for a drug is set at zero.11 Zero tolerance laws can also establish thresholds just above zero, to account for cases of prescription drug use or accidental exposure to a drug (e.g. passive inhalation of cannabis smoke).12 The emphasis of zero tolerance laws is placed on the presence of the drug as opposed to its impairing effects. The limitation of these laws is that some drugs such as THC may be stored in the fat cells of the body and can be detected several days after the drug’s impairing effects have subsided. As such, this approach to laws is often criticized as a drug-control measure designed to identify drug users, as opposed to a road safety law designed to identify impaired drivers.13

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3. What criminal penalties are applied to convicted drug-impaired drivers?

Criminal penalties applied in cases of drug-impaired driving vary across countries depending on the authority for criminal law. In Canada, criminal law is the responsibility of the Federal government and is uniform across all jurisdictions, whereas in the US criminal law is the responsibility of state governments and is different across jurisdictions. Generally speaking, penalties are often similar to those applied for alcohol-impaired driving and may include incarceration, periods of probationary sentences, substance abuse education or treatment, licence suspensions, alcohol ignition interlocks and/or fines. The severity of penalties increases in cases involving a crash causing death, injury, or property damage. Additionally, the severity of penalties can increase for repeat offences.

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4. Apart from criminal penalties, are there other types of penalties that can be applied to convicted drug-impaired drivers by provinces or states?

Apart from criminal penalties, convicted drug-impaired drivers may be subject to administrative laws and penalties. Administrative laws are enacted by provincial, state or territorial governments, and are typically administered by police agencies and/or licencing authorities (e.g., provincial ministries of transportation).14 Administrative laws can be applied at roadside or following a conviction for criminal charges. Often drivers are able to appeal to administrative courts in relation to due process issues or applied penalties. Common administrative penalties include licence suspensions, vehicle impoundment, administrative fines or fees, installation of an alcohol interlock device,15 and mandatory driver education remedial programs.14

15 An alcohol interlock is a device requires a breath sample from a driver to determine the presence of alcohol. A driver cannot start a vehicle following a breath sample in excess of a pre-determined BAC level. The interlock interrupts the flow of power to the starter to starting the vehicle.

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5. What are the current laws and penalties for drug-impaired driving?

Canada. While a per se limit is used for alcohol-impaired driving, Canada currently employs a behavioural impairment legislative approach to drug-impaired driving.

Under section 253(1)(a) of the Criminal Code of Canada (CCC), it is an offence to operate a vehicle while impaired by alcohol, a drug, or a combination thereof, and peace officers must collect and document evidence of behavioral impairment to charge a suspected impaired driver. In 2008, changes to the CCC under section 254, provided that drivers suspected of drug-impairment submit to the Standardized Field Sobriety Test (SFST).16 If the results of the SFST provide reasonable grounds to suspect drug-impairment, drivers can be required to undergo a DRE evaluation by a trained and certified police officer. This assessment involves a series of behavioural and cognitive tests that allow DRE officers to determine whether a driver is impaired by drug, and the class of drug(s) likely responsible for the impairment.17 If the DRE results indicate drug-based impairment, these officers can demand a bodily fluid sample from a driver for laboratory testing. Additional changes to Canadian impaired driving statutes have been proposed and are under discussion.18

Individuals convicted of drug-impaired driving may be subject to a licence suspension and a minimum fine of less than $1,000 for a first offence; jail time for at least 30 days for a second offence; and jail time or at least 120 days (to a maximum of 18 months for summary convictions, and five years for indictable offences)19, for every subsequent offence. Individuals convicted of impaired driving causing bodily harm can be sentenced to prison for a term of not more than 10 years, and those convicted of impaired driving causing death can be sentenced to prison for life (Section 255 (1) – (3), Criminal Code of Canada). Additionally, ten Canadian jurisdictions20 have administrative laws and penalties that can be applied to drivers suspected of being under the influence of drugs.21 Some Canadian jurisdictions only allow for a 24-hour roadside licence suspension; however Prince Edward Island and Newfoundland and Labrador enable police officers to suspend a driver’s licence for seven days if drug-impairment is suspected. British Columbia and Alberta also allow for vehicle impoundment for 24 hours in addition to a 24-hour licence suspension.22

As of October 2016, in Ontario these penalties have been amended through the “Making Ontario’s Roads Safer Act” and now include an immediate roadside licence suspension, possible vehicle impoundment and fines; additionally, the severity of penalties increases with subsequent offences, and is consistent with those applied to suspected alcohol-impaired drivers. Previously Ontario regulations only permitted police to suspend a driver’s licence for 90 days if the suspected impaired driver refused to cooperate with an SFST demand, submit to an examination by a DRE officer, or provide a bodily fluid sample.23

Additionally, Senate Bill S-230 has been introduced in the Senate of Canada. This Bill proposes revisions to section 254 (2) and (3.4) of the Canadian Criminal Code to facilitate the process of oral fluid testing for drugs by officers that investigate suspected impaired drivers. Specifically, this change proposes to permit for peace officers to demand oral fluid or urine from suspected drivers depending upon which test, in the officer’s opinion, would provide a more accurate measure to determine if they are impaired due to drugs. The main goal of this bill is to enable officers to collect oral fluid similar to the way breath samples are collected for alcohol-impaired driving. This is because drugs are more readily detected in saliva or blood whereas alcohol is more readily detected in breath; something that the current legislative scheme does not address.

United States. Criminal law is under state authority. Each state has its own set of laws about drug-impaired driving:

  • A majority of states have criminal impairment-based laws;
  • 16 states24 have enacted zero tolerance laws;
  • 6 states25 have established per se laws for one or more drugs.26

With respect to marijuana-impaired driving:

  • 9 states27 have established zero tolerance laws for the presence of THC and its metabolites;
  • 3 states28 have established zero tolerance laws for the presence of THC without restrictions on metabolites;
  • 5 states29 have defined per se limits for THC; and,
  • 1 state (Colorado), has established a reasonable inference law for THC with a per se limit of 5 ng/ml.

States that have not established zero tolerance or per se laws, utilize an impairment-based legislative approach to drug-impaired driving. Drivers are deemed impaired if their ability to safely operate a vehicle is affected by the use of alcohol and/or drugs, as assessed by a trained law enforcement officer.30 Additionally, in states with impairment-based legislation, law enforcement officers must directly link observed impairment to the presence of a specific category of drug in order to file a charge.

For the majority of states, impaired-driving legislation is contained within transportation and motor vehicle codes, with the exception of Idaho and Texas, which have included impaired driving laws in their criminal codes.31 According to Jonah (2014), none of the states have administrative laws for drug-impaired driving, and all states require drivers charged with a drug-impaired driving charge to appear in criminal court. Criminal penalties for drug-impaired driving convictions vary from state to state, but are often similar to those imposed for alcohol-impaired driving.

For example, in Colorado, drug- or alcohol-impaired drivers may be charged with different types of impaired driving offences. Suspected impaired drivers can be charged with either driving while ability impaired (DWAI) and driving under the influence (DUI) offences while in Colorado.32 In some cases they may be charged with both types of offences. A 1st DWAI conviction results in a jail sentence ranging from 2 days to 180 days, a fine between $200 and $500, and mandatory public services of 24 hours to 48 hours. A 1st DUI conviction results in a jail sentence of 5 days to one year, a fine of $600 to $1,000, and mandatory public service of 48 hours to 96 hours.33 Each subsequent conviction results in longer jail sentences and larger fines.

Europe. Drug-impaired driving legislation varies widely across Europe.34 According to a summary of drug-impaired driving laws in 26 European Countries, conducted by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) in 2011:

  • 3 countries35 have only non-criminal offences for drug-impaired driving (statutes include two types of law, administrative or civil, and two types of offences, minor or misdemeanor);
  • 7 countries36 have both non-criminal and criminal offences;
  • 16 countries37 have only criminal offences;
  • 10 countries38 have an impairment-based legislative approach to drug-impaired driving;
  • 2 countries39 have an “impairment above defined limits” approach;
  • 8 countries40 have adopted per se or zero tolerance laws;
  • 6 countries41 have a combination of impairment-based legislation and zero-tolerance/per se laws; and,
  • 16 countries42 have set non-zero per se thresholds for cannabis, ranging from a THC concentration of 0.3 μg/L to 5.0 μg/L in blood or blood serum.43

Penalties for drug-impaired driving also vary widely across European countries and prison sentences may range from a few days to years, licence suspensions may range from a few months to five years, and fines may be as low as a few hundred euros (€) to as large as several thousand euros, depending on the country in question.44 Specific examples from Norway and France are described below as illustration of penalties.

  • Norway
    • Legislation. Norway has established per se limits for 28 drugs, including both medicinal and illegal drugs. These limits were determined by an expert panel based in part on a comprehensive review of experimental studies. These limits are considered to reflect the concentrations at which impairment comparable to a BAC of 0.02% would be observed, and 22 out of the 28 drugs have limits for graded sanction corresponding to a BAC of 0.05% and 0.12%.
    • Results from a roadside survey of alcohol and drugs in Norwegian drivers in 2016-2017 were compared to a roadside survey conducted prior to the implementation of these legislative limits, and a significant decrease in the prevalence of benzodiazepine and amphetamines was found. 45
    • Penalties. Upon conviction for a drug-impaired driving offence, Norwegian drivers are subject to a licence suspension period for a minimum of one year, to a fine 1.5 times their gross monthly income (usually not under NOK 10,000) and can receive up to a year in prison.46
  • France
    • Legislation. France has a zero tolerance legislative approach to drug-impaired driving.
    • Penalties. Upon conviction of a drug-impaired driving offence, drivers are subject to a licence suspension period of up to three years, can be fined 4,500€ or 9,000€ (if alcohol is also detected), and receive a prison sentence of two or three years, if alcohol is also detected.47

Australia. The current laws and penalties for drug-impaired driving in Australia vary by jurisdiction.

  • Victoria
    • Legislation. In 2004 Victoria introduced random roadside drug testing (RDT) legislation and implemented a roadside oral-fluid screening device (Securetec Drug Wipe II), making it the first Australian jurisdiction to do so.48 A zero tolerance approach was adopted for THC, methamphetamine, and MDMA.
    • Penalties. In Victoria, conviction for a drug-impaired driving first offence includes a fine of $423 AUD, and a possible three month licence suspension. If drivers were not deemed to be impaired by the drug (only the presence of the drug was detected), then administrative penalties, including a $307 AUD fine and three demerit points, are applied to the driving licence.49 A 24-hour roadside suspension is applied to any drug positive result.50
  • South Australia
    • Legislation. RDT legislation was introduced in 2005 and a zero tolerance approach was adopted for THC, methamphetamine, and MDMA.
    • Penalties. In South Australia, a positive THC oral fluid test results in a police directive to the driver to abstain from driving for five hours, and a positive methamphetamine or MDMA test results in a directive to abstain from driving for 24 hours. Failure to comply can result in drivers being arrested for disobeying a police directive.51 A drug-positive result in South Australia can result in either a fine of $523 AUD and four demerit points applied to the licence, or a drug charge that, upon conviction, carries a $1,600 AUD fine, imprisonment for up to three months, six demerit points, and a 12-month licence suspension for first offenders.52
  • Queensland
    • Legislation. RDT legislation was introduced in 2007 and a zero tolerance approach was adopted for THC, methamphetamine, and MDMA.
    • Penalties. In Queensland, drivers testing positive for drugs are subject to a $1,050 AUD fine and a nine-month licence suspension for first offenders. A roadside suspension of 24-hours is also applied to drivers with any drug-positive test results.53
  • Tasmania
    • Legislation. RDT legislation was introduced in 2005. Tasmania has established prescribed limits for a wider range of drugs, including: amphetamine, cocaine, THC, heroin, GHB, ketamine, LSD, Quaalude, MDMA, morphine, diethyltryptamine, dimethyltryptamine, PCP, and psilocybin.54
    • Penalties. In Tasmania, the penalty for a drug-positive result includes two to 10 demerit points, imprisonment for up to three months, and/or a fine.55
  • New South Wales
    • Legislation. RDT legislation was introduced in 2006 and a zero tolerance approach was adopted for THC, methamphetamine, and MDMA.
    • Penalties. A drug-positive result in New South Wales can result in a charge of driving while under the influence of an illicit drug, which upon conviction, carries of penalty of $1,100 AUD fine and a six-month licence suspension for first offenders.56 A 24-hour roadside suspension is applied to any drug-positive test results.57
  • Western Australia
    • Legislation. RDT legislation was introduced in 2007.
    • Penalties. In Western Australia, one of three potential charges can result from a drug-positive result, including, a charge that carries a $500 AUD fine and three demerit points, an administrative traffic infringement penalty, or a driving under the influence of a prescribed drug charge which carries a $2,500 AUD fine and a 10-month licence suspension.58
  • Northern Territory
    • Legislation. RDT legislation was introduced in 2008.
    • Penalties. Upon conviction first offenders are subject to a $400 AUD fine and/or a term of imprisonment no longer than three months.
  • Australian Capital Territory
    • Legislation. RDT legislation was introduced in 2011.
    • Penalties. First offenders can be charged a fine up to $1500 AUD. Repeat offenders can be charged a fine of up to $3,750 AUD and/or be given three months imprisonment. Offenders can also lose their driver’s licence for a period specified by the court.

19 A summary conviction is an offence which can be acted upon without the need for a jury trial and/or indictment. An indictable offence requires either a preliminary hearing or a grand jury. Offenders generally have the right to a trial by jury for indictable offences unless they forgo that right. Hybrid offences are offences that can be prosecuted by either summary conviction or indictment, and the prosecution is able to elect which an offence is to be tried. Impaired driving is a hybrid offence.
32 DWAI is considered a lesser offence and is generally applied when someone has a BAC level between 0.05-0.08. DUI is a more serious offence and is typically applied when someone’s BAC is over 0.08. DWAI offences are determined by both BAC level and the observed behaviour of the driver while DUI offences are determined by whether or not a driver’s BAC level is over the legal limit.

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6. Have the different types of laws and penalties used to manage drug-impaired driving been evaluated, in terms of reducing the prevalence of drug-impaired driving and preventing repeat drug-impaired driving offences?

Laws and penalties for drug-impaired driving offences have been evaluated across various jurisdictions in terms of reducing the prevalence and recidivism59 however there are not many recent evaluations. Most of these evaluations pertain to alcohol-impaired driving offences. According to studies about the effectiveness of these laws for drug-impaired driving, the general consensus is that more research is needed since many questions about their effectiveness remain unanswered.

a) Have behavioural impairment laws been evaluated, and if so, what is known about their effectiveness?

There is a vast body of research that examines the effectiveness of behavioural impairment laws and the effect of these laws on both alcohol-impaired driving and drug-impaired driving.

Evaluations involving alcohol-impaired driving have shown that behavioural impairment laws are not as effective as per se laws as a tool to regulate alcohol-impaired driving. Specifically, the shift from behavioural impairment laws to per se laws for alcohol-impaired driving appears to have been a turning point at which alcohol-related driver fatalities began to decline following their implementation.60 However, this approach requires a demonstrable per se limit, that is supported by scientific evidence as constituting impairment, and a device that can accurately measure the specified threshold at which drivers are impaired and unable to safely operate a motor vehicle.

Conversely, in 2016, behavioural impairment laws are viewed as more viable than per se laws for drug-impaired driving due to the lack of scientific consensus regarding impairment at specified thresholds of individual drugs. Generally, it is believed that more research is needed to accurately determine a person’s level of impairment based upon the quantity of drugs they have in their system.61 In the absence of definitive research to demonstrate that a specific amount of consumed drug results in a certain level of impairment for all users, it is challenging to establish a precise per se limit. For this reason it has generally been acknowledged that behavioural impairment laws are the most effective and practicable strategy to manage drug impaired driving offences.

However, it is also recognized that there are challenges associated with proving behavioural impairment. Officers must rely upon multiple indicators such as erratic driving, non-responsive behaviour and several other validated criteria, which makes the enforcement of these laws complex. As a consequence, when drugs are present in combination with alcohol it often more efficient to pursue alcohol-impaired charges due to a robust body of scientific evidence regarding alcohol and its impairing effects.62

b) Have per se laws been evaluated, and if so, what is known about their effectiveness?

Per se laws have been evaluated although a majority of these evaluations examine alcohol-impaired driving. According to the research investigating per se limits for alcohol-impaired driving, it has been established that per se limits do have an overall reduction effect on incidents of alcohol-related impaired driving fatalities in North American jurisdictions.63

The use of per se limits for drug-impaired driving is more complex in comparison to per se limits for alcohol. Unlike drugs, alcohol has a clear dose-response relationship, meaning that drivers are similarly impaired when a specified volume of alcohol is consumed. Conversely, a consistent dose-response relationship has not been demonstrated for drugs and this makes it challenging to reach consensus regarding specific per se limits for different drugs, and equating a per se limit for drugs to a .08 or .10 BAC for all users.64

In jurisdictions where per se limits for drugs have been implemented it is hard to measure the effects of these laws on the prevalence of drug-impaired driving and rates of recidivism. If prevalence is understood to be a function of deterrence, it appears the effects are minimal since per se limits may initially increase offence rates. However, this increase may be largely due to the fact that the level of enforcement increased after the legislation was passed and police could lay charges on the basis of per se limits alone.65

In terms of effects on drug-impaired driving recidivism rates, the data are inclusive. This is mainly due to a lack of established reporting systems that can accurately distinguish between and track the trajectory of alcohol-impaired driving cases versus drug-impaired driving cases.66

Despite these challenges, there is some evidence that the adoption of per se limits for drug-impaired driving would be positively received by traffic safety officials.67 This appears to be due to beliefs that the process of prosecuting drug-impaired drivers would be more similar to the process of prosecuting alcohol-impaired drivers. Specifically, traffic safety officials noted that in jurisdictions that do have per se limits for drug-impaired driving, officers are often able to charge individuals according to the evidence that is most readily available, and that will be more likely to result in a conviction, as opposed to having to rely on the evidence and documentation gathered by a DRE.68 As such, the use of per se limits would facilitate the detection and arrest of drug-impaired drivers, even if officers are not trained and certified as DREs.

c) Have zero tolerance laws been evaluated, and if so, what do we know about their effectiveness?

The effectiveness of zero tolerance laws, as they pertain to alcohol-impaired and drug-impaired driving, have been regularly evaluated.

Zero tolerance laws for alcohol-impaired driving are primarily aimed at preventing young people (aged 21 years and under) and commercial vehicle drivers from driving with alcohol in their system.69 The effectiveness of zero tolerance laws in this regard varies since these laws may not be easily or consistently enforced, and those who are affected by such laws are not always aware of them. For example, two-thirds of youth surveyed in New Mexico were unaware of laws prohibiting young people from driving after consuming any amount of alcohol.70 However, despite low awareness, there is data to suggest that zero tolerance laws do have a measurable effect on reducing the number of alcohol-related fatal crashes.71 Still, the overall impact of zero tolerance laws is difficult to measure because these laws are not consistently enforced across all jurisdictions due to the difficulty of detecting drivers with low-BACs.

Zero tolerance laws which are aimed at drug use when driving have been argued to be much more practical than per se limits due to the complexity of the science associated with selecting a per se limit for each drug.72 However it is also recognized that a small quantity of drugs may be present in the body due to prescription/over-the-counter drug use and/or accidental exposure, and these instances should be considered in legislation to ensure criminal penalties are not applied in these specific instances.73

Research evaluating the effectiveness of zero tolerance laws in reducing the prevalence of drug-impaired driving has shown that arrest rates generally increase in some jurisdictions that use this approach, and convictions as well.74 Unfortunately, these evaluations also show that recidivism remains high among those convicted, and repeat offenders pose a burden upon the system.75

It is generally acknowledged that repeat offenders represent a demographic of drug-impaired driving offenders that have serious issues with substance abuse.76 In such cases, there is general consensus that stricter penalties and laws may be inadequate to effectively combat this issue, and treatment options should be explored.77

d) Have prison and jail sentences as a penalty for impaired-driving been evaluated, and if so, what is known about their effectiveness?

Evaluations of the effectiveness of prison and jail sentences to reduce the prevalence of impaired driving show that these measures have not had a consistent deterrent effect. In particular, research that examined the impact of increasing the severity of sentencing penalties revealed that there was not a measurable general or specific deterrent effect. One of the explanations for these results is that, although penalties have increased in legislation, these higher penalties were not consistently applied by the courts during sentencing.78

Similarly, there is consensus that harsher penalties in the form of jail time and prison sentences do not substantially reduce recidivism rates.79 Hence while periods of incarceration serve to punish offenders, research suggests that these sanctions do not have a strong deterrent effect on first and repeat offenders.80

In fact, research suggests that evidence-based treatment programs are a more effective strategy to reduce risk in the long-term, and offenders who are substance dependent or substance abusers may benefit more from these approaches in comparison to incarceration.81

e) Have probation/community supervision and parole sentences as a penalty for impaired-driving been evaluated, and if so, what do we know about their effectiveness?

Probation82 and parole83 sentences for impaired driving have been evaluated, and similarities between probation and parole sentences make it possible to summarize these results. Probation and parole officers estimate that almost 50 percent of impaired driving offenders do not adhere to terms and conditions of their probation.84 The reasons cited for this problem were mainly a lack of effective monitoring strategies, the absence of the authority to impose sanctions for instances of non-compliance, and ineffective communication protocols.85 Nonetheless, officers reported that non-compliance with sanctions is more often detected when offenders are observed in community settings. As a result, officers have proposed that more active supervision in community settings would be more informative and aid monitoring rather than individual in-person meetings at specified times at the probation office.86

Of note, the evaluations of the effectiveness of these sanctions have focused mainly on alcohol-impaired driving offenders, and it is unclear whether drug-impaired drivers share the same characteristics and can be effectively supervised using these strategies. In other words, more research is needed to identify the types of strategies that may be best suited to drug-impaired drivers.

f) Have licence suspensions for impaired-driving been evaluated, and if so, what is known about their effectiveness?

Research examining the effectiveness of administrative licence suspensions for impaired-driving indicates that the use of licence suspensions has a measurable impact upon driver behaviour. However, there is also data to suggest that licence suspensions alone are inadequate to change driver behaviour in the long-term, and that such suspensions should be augmented with other administrative measures. For example, studies showed that licence suspensions are most effective when the physical licence is surrendered rather than allowing it to be retained by suspended drivers. Suspended drivers that are able to retain their physical licence can more easily avoid detection by producing what appears to be a valid licence if they are stopped again by police, or travel through a checkpoint.87 Data suggests that, among those drivers who do have their licence suspended, a majority of them continue to drive as they realize the likelihood of detection for unlicensed driving is nominal, although they may drive less frequently and more cautiously.88

An important limitation to these studies is the difficulty distinguishing between drivers who are suspended for alcohol- and/or drug-impaired driving offences, as compared to drivers who are suspended for other types of traffic violations. In other words, a driver’s licence may be suspended for a wide variety of reasons unrelated to substance abuse and driving.89 As such, it has been difficult to measure the use of licence suspensions for specific types of offences and violations.

g) Has vehicle impoundment for impaired-driving been evaluated, and if so, what is known about its effectiveness?

Several evaluations of the effectiveness of vehicle impoundment programs on impaired driving have been conducted. Below a short summary of this research is provided in relation to both vehicle impoundment (i.e., when the actual vehicle is confiscated and stored) and plate impoundment (i.e., when only the licence plate is confiscated).

  • Vehicle impoundment. In many jurisdictions vehicle impoundment is viewed as a “last resort” for repeat/persistent impaired driving offenders.90 Vehicle impoundment has been shown to be an effective countermeasure wherever it is implemented.91 However, major limitations include the cost of the actual physical impoundment of the vehicle, as it must be either confiscated and stored or rendered immobile, as well as the process to manage vehicles that are impounded and collect fines and fees associated with this process.92
  • Plate impoundment. An alternative to vehicle impoundment is plate impoundment. Plate impoundment involves the confiscation of the licence plate of a vehicle by the state. In Minnesota, the licence plate is considered the property of the state and is therefore subject to seizure. This is considered an important distinction as it makes it easier to conduct plate seizure. However, in light of safety concerns associated with the removal of the plate at roadside by officers, another effective way to detect unlicensed drivers is to use a “zebra tag” which are striped markers placed over the annual sticker to designate an unlicenced driver.93 Ultimately studies have shown that plate impoundment is a cost-effective alternative to vehicle impoundment that does have a measurable impact on recidivism.94 In particular, the zebra tag process also poses lower risk to officer safety in that it is easier to apply a sticker to a plate than to physically remove the plate at the roadside.

Best practices have also shown that vehicle/plate impoundment is more effective when it is implemented as an administrative sanction rather than a court sanction.95 Despite these encouraging results, research has also revealed that vehicle/plate impoundment is most effective when tangible treatment options are also offered as part of the program. While the use of impoundment can be an effective strategy for alcohol-impaired driving, studies which research the effect of this strategy for drug-impaired driving are limited.96

59 Prevalence can be understood here to mean how often the crime is committed (i.e. how many people are deterred from offending) and recidivism can be understood to mean how often offenders re-commit the offence.
81 There is an important distinction between abusers and dependants. Abusers are individuals that do not rely upon substances in order to function and have sufficient ability to stop taking their respective substance. Dependants are those who rely upon substances in order to function and are considered addicted. It should also be understood that the use of the word “substance” here can mean either alcohol or drugs.
82 Probation refers to a judicial order/suspended sentence that is served under the supervision of the community and as such can be interchangeably called “community supervision”.
83 Parole is post-release supervision which is granted after serving a longer period of incarceration and is monitored by parole officers. The conditions of parole are similar to probation, however parole is strictly a post-release sanction whereas probation is in lieu of incarceration.

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Post-Conviction Programs

7. What are drug courts, and how are they applied to drug-impaired drivers?

Drug courts are courts that deal specifically with drug-related offences. Studies have shown that drug courts have been highly effective strategy to address the risks and needs of offenders in order to effectively treat drug-related issues.97 However, such research has also shown that drug courts are resource intensive and require specialized services that may not be possible to provide in all jurisdictions, specifically in urban jurisdictions where the offender population is larger or in smaller jurisdictions where there are fewer resources generally, and limited treatment services specifically.

Research has also revealed that the effect of drug courts on drug-impaired driving offenders is minimal, although it is generally agreed that more research must be undertaken in this area. Specifically, it remains to be seen whether or not drug courts could have a significant impact on drug-impaired driving offenders if the services offered were better-tailored to their specific needs.98

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8. What are DWI (Driving While Impaired) Courts?

DWI courts are specialized courts that deal specifically with alcohol-impaired driving offences. There are two main types of DWI courts: hybrid drug/DWI courts and stand-alone DWI courts. Hybrid courts deal with drug/alcohol substance abuse offences including alcohol-impaired driving offences. Stand-alone DWI courts strictly deal with alcohol-impaired driving offenders. Brief summaries about the effectiveness of each type of court are below.

  • Hybrid courts. There have not been many evaluations of hybrid courts. The reason for this is because hybrid courts are established for a number of different reasons and are not necessarily comparable in terms of the types of offenders who are eligible to participate which can make evaluation more complex. Of the evaluations that do exist it has been reported that, overall, the reported effectiveness of hybrid courts has been variable.99 The reduction in recidivism rates among hybrid courts did not differ much from the recidivism rates of those who undergo other sanctions such as prison sentences or periods of probation.100
  • Stand-alone courts. Research has found that stand-alone DWI courts generally have more consistent success than hybrid courts. For example, research conducted in Michigan found that traditional DWI courts alone, as well as DWI courts that utilized ignition interlocks, were extremely effective at reducing recidivism, being even more effective than probation supervision, although the level of resources associated with probation supervision was lower.101 Studies have shown that it is not advisable to mix alcohol-impaired driving offenders into traditional drug treatment programs which may not be equipped to address their specific needs.102

Generally speaking, research suggests that an effective long-term risk reduction strategy is to ensure that DWI court programs, whether hybrid or stand-alone, pursue evidence-based strategies that appropriately meet the needs of all offenders that are enrolled in the court.103

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9. Are drug-impaired drivers in the U.S. required to abstain from drug and alcohol use after conviction? How are they monitored or tested for drug and alcohol use post-conviction?

In Canada, abstinence from alcohol and drug use is not a standard requirement of sentencing upon conviction, although it may be applied in some circumstances, and continuous alcohol monitoring tools are not often utilized.

Abstinence is frequently a condition of sentencing or probation supervision in most US jurisdictions. However, the tools and practices used to monitor abstinence vary widely and may include random testing, home visits, and continuous alcohol monitoring. Perhaps the most recognized example of monitoring for abstinence is the 24/7 p sobriety program in South Dakota. Offenders are tested for alcohol twice at the local Sheriff’s Office, and may also be required to wear a drug patch and/or use a continuous alcohol monitor. Offenders who test positive for alcohol and/or drugs are subject to escalating sanctions.104

Due to the reported success of these programs in rural areas there has been some speculation that these programs may be scaled to an urban model. However, only one major research study has investigated this topic and the results have shown that there are substantial logistical issues at present that would make this strategy quite impractical in larger jurisdictions.105

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10. What are remedial driver licencing programs, how are they applied to drug-impaired drivers?

Offenders that are convicted of impaired driving offences, or that have accumulated multiple administrative, low-BAC offences (which are specific to Canada) may be required to complete a remedial driver program before being eligible for re-licensing. Remedial programs may consist of an alcohol education program, an assessment for substance use, and/or treatment depending on the type of conviction.106

Research suggests that remedial driver licensing programs for impaired drivers contain a number of strengths such as: an individualized approach, pursuit of evidence-based solutions, well-trained practitioners, and well-established lines of communications.107

However, there are also several limitations to these programs that may limit their effectiveness.108 Some recommendations that have been offered to increase the effectiveness of these programs are: improve quality of risk assessment instruments that are utilized, increase training for staff, increase emphasis on prevention activities, encourage the use of best practices, strengthen program measures, provide transportation options, increase communication and information-sharing, and explore the need for tailored programs and services for younger participants.109

There is limited research available that measures the impact of these programs as they relate to drug use. Studies do suggest that remedial programs do help reduce recidivism among offenders, however this research was in relation to alcohol-related offences.110 In 2004, Health Canada released a report that summarized best practices of remedial alcohol-impaired driving programs, but the effectiveness of such practices with drug-impaired drivers has not been investigated.111

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11. Could a device similar to an ignition interlock, which is used to monitor convicted alcohol-impaired drivers, ever be used for drug-impaired drivers?

Current alcohol ignition interlock technology is not designed to measure drug-impairment. That being said, there is some speculation a certain amount of marijuana smoke in the breath can be detected on a breath testing device, similar to an approved screening device (ASD) or a preliminary breath test (PBT).

Cannabix Technologies Inc. is currently developing a breathalyzer which specifically measures THC levels in breath samples. Their aim is to develop technologies that are portable and can be used to measure levels of impairment at roadsides.112

However, a functioning breathalyzer that specifically measures drug-impairment is not likely to be available to prevent convicted impaired drivers from starting their vehicle after consuming THC in the near future. Furthermore, given that cannabis is most often consumed in conjunction with alcohol, it is difficult to accurately establish levels of THC that would constitute drug-impairment in combination with varying amounts of alcohol.113 This is why these types of technologies can be used to suggest impairment, along with other indicators, but may be difficult to rely on as the sole indicator of impairment and may not be appropriate to use as a post-conviction sanction similar to an interlock.

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Laws based on behavioural impairment, per se thresholds, and zero tolerance have different strengths and limitations, and the enforcement of these laws can be challenging for different reasons. While per se laws have been an effective solution to manage alcohol-impaired driving, the different effects of specific drugs on individual users may make this a more challenging proposition for drug-impaired driving offences according to current research. Therefore, behavioural impairment laws are generally viewed as more viable than per se laws due to the lack of scientific consensus regarding drug impairment at specified thresholds.

Research evaluating the effectiveness of programs and policies specific to drug-impaired driving is currently limited, and more research regarding the characteristics of drug-impaired drivers is needed to develop evidence-based solutions to reduce this risky behaviour. Going forward, the tailoring of strategies to address risks and needs, and reduce risk are important considerations, and the “over-servicing” of offenders who pose less risk should be avoided.

  • Asbridge, M., Mann, R. E., Flam-Zalcman, R., & Stoduto, G. (2004). The criminalization of impaired driving in Canada: assessing the deterrent impact of Canada’s first per se law. Journal of studies on alcohol, 65(4), 450-459.
  • Baldock, M., & Woolley, J. (2013). Reviews of the effectiveness of random drug testing in Australia: the absence of crash-based evaluations. ACRS.
  • Beirness, D.J., & Beasley, E.E. (2011). Alcohol and drug use among drivers: British Columbia Roadside Survey 2010. Ottawa, ON: Canadian Centre on Substance Abuse
  • Bouffard, J. A., & Richardson, K. A. (2007). The Effectiveness of Drug Court Programming for Specific Kinds of Offenders Methamphetamine and DWI Offenders Versus Other Drug-Involved Offenders. Criminal Justice Policy Review, 18(3), 274-293.
  • Bouffard, J. A., Richardson, K. A., & Franklin, T. (2010). Drug courts for DWI offenders? The effectiveness of two hybrid drug courts on DWI offenders. Journal of Criminal Justice, 38(1), 25-33.
  • Briscoe, S. (2004). Raising the bar: can increased statutory penalties deter drink-drivers? Accident Analysis & Prevention, 36(5), 919-929.
  • Canada. Parliament. House of Commons. “Impaired Driving Act” Bill C-226, 42nd Parliament, 1st Session, 2016. Ottawa: Public Works and Government Services Canada – In Committee (House), June 9th 2016.
  • Canadian Centre on Substance Abuse (2016) Facts about Drug-Impaired Driving. Ottawa, ON: Canadian Centre on Substance Abuse. Retrieved online:
  • Cavanaugh, M. R., & Franklin, T. W. (2012). Do DWI courts work? An empirical evaluation of a Texas DWI court. Journal of Offender Rehabilitation, 51(4), 257-274.
  • Caulkins, J. P., & DuPont, R. L. (2010). Is 24/7 sobriety a good goal for repeat driving under the influence (DUI) offenders?. Addiction, 105(4), 575-577.
  • Centre for Addition and Mental Health. (2014). Cannabis policy framework. Centre for Addiction and Mental Health website. Retrieved online:
  • Coben, J. H., & Larkin, G. L. (1999). “Effectiveness of ignition interlock devices in reducing drunk driving recidivism”. American Journal of Preventive Medicine, 16(1), 81-87.
  • Compton, R., Vegega, M., & Smither, D. (2009). Drug-Impaired Driving: Understanding the Problem and Ways to Reduce It: A Report to Congress (No. HS-811 268).
  • European Monitoring Centre for Drugs, & Drug Addiction. (2011). Annual Report on the State of the Drugs Problem in the European Union (Vol. 2011). European Monitoring Centre for Drugs and Drug Addiction.
  • Fell, J. (1995). “Repeat DWI offenders in the United States”. Traffic tech: Technology transfer series, 85. Retrieved online:
  • Ferguson, S. A., & Williams, A. F. (2002). Awareness of zero tolerance laws in three states. Journal of safety research, 33(3), 293-299.
  • Fisher, D. A., McKnight, A. S., & Fell, J. C. (2013). Intensive DWI supervision in urban areas—Feasibility study (No. DOT HS 811 861).
  • Furuhaugen, H., Jamt, R. E., Nilsson, G., Vindenes, V., & Gjerde, H. (2018). Roadside survey of alcohol and drug use among Norwegian drivers in 2016–2017: A follow-up of the 2008–2009 survey. Traffic injury prevention, 19(6), 555-562.
  • Grotenhermen, F., Leson, G., Berghaus, G., Drummer, O. H., Krüger, H. P., Longo, M., … & Tunbridge, R. (2007). “Developing limits for driving under cannabis”. Addiction, 102(12), 1910-1917.
  • Hedlund, J. (2015, 2016, Curr. Ed. 2017). “Drug Impaired Driving: A Guide for What States Can Do”. Governors Highway Safety Association. Retrieved online:
  • Health Canada (2004). Best Practices – Treatment and Rehabilitation for Driving While Impaired Offenders. Health Canada. Ottawa, ON. ISBN 0-662-37448-7.
  • Holmes, E., Vanlaar, W., & Robertson, R., (2014). The problem of youth drugged driving and approaches to prevention: A systematic literature review. Ottawa, ON: Canadian Centre on Substance Abuse
  • Holmgren, A., Holmgren, P., Kugelberg, F. C., Jones, A. W., & Ahlner, J. (2008). High re-arrest rates among drug-impaired drivers despite zero-tolerance legislation. Accident Analysis & Prevention, 40(2), 534-540.
  • Innoventures Canada (2016) Impairment Detection Technologies – What does Canada need? I-CAN Workshop Discussion. National Optics Institute.
  • Jonah, B. A. (1997). Sensation seeking and risky driving: a review and synthesis of the literature. Accident Analysis & Prevention, 29(5), 651-665.
  • Jonah, B.A. (2014) “Administrative laws for drugs and driving inside and outside Canada. Canadian Council of Motor Transport Administrators”. Canadian Council of Motor Transportation. Administrators Retrieved online:
  • Jones, A. W. (2005). Driving under the influence of drugs in Sweden with zero concentration limits in blood for controlled substances. Traffic injury prevention, 6(4), 317-322.
  • Kierkus, C.A. & Johnson, B.R. (2012). Michigan DWI/Sobriety Court Ignition Interlock Evaluation: 2012 Report. Michigan Association of Drug Court Professionals.
  • Lacey, J., Brainard, K., & Snitow, S. (2010). “Drug per se laws: A review of their use in States” NHTSA. No. HS-811 317. Retrieved online:
  • Leaf, W. A., & Preusser, D. F. (2011). Evaluation of Minnesota’s vehicle plate impoundment law for impaired drivers (No. HS-811 351).
  • Marlowe, D. B. (2012). The facts on DWI courts. Washington State Sentencing Guidelines Commission. Retrieved September, 23, 2015.
  • NHTSA (2013) Summary of State Speed Laws: 12th Edition. NHTSA. No. HS 811 769 retrieved online:
  • No DUI Colorado (2016) Criminal Penalties and Fines. Retrieved online at:
  • Parrish, K. E. (2013). The Problem of Suspended and Revoked Drivers who Avoid Detection at DUI/license Checkpoints (No. CAL-DMV-RSS-13-244).
  • Robertson, A. A., Gardner, S., Xu, X., & Costello, H. (2009). The impact of remedial intervention on 3-year recidivism among first-time DUI offenders in Mississippi. Accident Analysis & Prevention, 41(5), 1080-1086.
  • Robertson, R.; Simpson, H (2003) DWI System Improvements for Dealing with Hard Core Drinking Drivers. Traffic Injury Research Foundation. Ottawa, ON. ISBN: 0-920071-35-X
  • Robertson, R.D., & Wood, K.M. (2013). Impaired Driving Risk Assessment: A Primer for Policymakers. Traffic Injury Research Foundation. Ottawa, ON.
  • Robertson, R. D., Woods-Fry, H., & Morris, K. (2016). The Traffic Injury Research Foundation.
  • Ross, H. L., McCleary, R., & LaFree, G. (1990). Can mandatory jail laws deter drunk driving? The Arizona case. The Journal of Criminal Law and Criminology (1973-), 81(1), 156-170.
  • Stohr, M. K., Willits, D. W., Makin, D. A., Hemmens, C., Lovrich, N. P., Stanton Sr, D. L., & Meize, M. (2020). Effects of Marijuana Legalization on Law Enforcement and Crime: Executive Summary. Annotation.
  • Sweedler, B. M., & Stewart, K. (2000). Vehicle sanctions: An effective means to reduce impaired driving. Alcohol, Drugs and Traffic Safety, 22-26.
  • Sweedler, B. M., Stewart, K., & Voas, R. B. (2004, August). Impaired driving: Vehicle sanctions around the world. In The Proceedings of the 17th International Conference on Alcohol, Drugs, and Traffic Safety, Glasgow, Scotland.
  • Vindenes, V., Sloerdal, L., & Moerland, J. (2013). Impairment based legislative limits for driving under the influence of non‐alcohol drugs: the Norwegian experience. 20th International Conference on Alcohol, Drugs and Traffic Safety Conference Proceedings, Brisbane Convention and Exhibition Centre, Brisbane, Australia (747-752).
  • Voas, R.B., Fell, J.C., McKnight, A.S., & Sweedler, B. M. (2004). Controlling impaired driving through vehicle programs: An overview. Traffic injury prevention, 5(3), 292-298.
  • Voas, R.B.; Tippetts, A.S. (1994) Assessment of Impoundment and Forfeiture Laws for Drivers Convicted of DUI, Phase II Report: Evaluation of Oregon and Washington Vehicle Plate Zebra Sticker Laws. DOT HS 808 136.
  • Voas, R.B., Tippetts, A.S., & Fell, J.C. (2003). Assessing the effectiveness of minimum legal drinking age and zero tolerance laws in the United States. Accident Analysis & Prevention, 35(4), 579-587.
  • Wong, K., Brady, J. E., & Li, G. (2014). “Establishing legal limits for driving under the influence of marijuana”. Injury epidemiology, 1(1), 26.
  • 24/7 program: A post-conviction program that grants offenders an unrestricted driving privilege in exchange for daily alcohol and drug testing to measure sobriety. Participants are required to report for alcohol and/or drug testing twice a day at a pre-determined facility, and may also be required to wear a drug patch and/or use a continuous alcohol monitor. Offenders who test positive for alcohol and/or drugs are subject to escalating sanctions.
  • Administrative hearing: A driver may request a hearing to contest an action or sanction against their driving privilege that was imposed by a driver licensing agency on a variety of grounds. The purpose of the hearing is to permit drivers an opportunity to review the evidence and contest the action. Drivers are informed about the legal grounds for the action, and are able to present evidence, witnesses and testimony to support a request to the licensing agency to modify or rescind the action. Hearings are typically recorded and rules applying to hearings are specified by the licensing agency.
  • Aerosols: A substance contained under pressure and able to be released as a fine spray, typically by means of a propellant gas. When used as a recreational drug, aerosols are classified as an inhalant.
  • Alcohol ignition interlock: An alcohol ignition interlock is a breath testing device that connects to the starter or ignition, or other on-board computer system of a vehicle. The device prevents the vehicle from starting if breath test results shows a breath alcohol concentration (BrAC) is found to exceed a certain pre-set limit (usually corresponding to blood alcohol concentration of .02). This device also requires drivers to continue to pass repeated breath tests while the vehicle is in use to ensure that they remain sober. In addition, these programmable devices possess a range of anti-circumvention features.
  • Alcohol-impaired driving: A criminal offence whereby one’s driving ability is impaired due to the consumption of alcohol in excess of a legal threshold. Jurisdictions often utilize a per se limit of .05 to .08mg/%. In addition to a per se limit, many jurisdictions also have an alcohol-impaired driving offence that is based on behavioural indicators of impairment which permits drivers under the per se limit to also be charged with an offence.
  • Amphetamine: Amphetamines are a synthetic, addictive, mood altering drug and are classified as a CNS stimulant drug.
  • Anti-anxiety tranquillizers: A tranquilizer is a drug that acts on the central nervous system and is used to calm, decrease anxiety, or help a person to sleep. Often called depressants because they suppress the central nervous system and slow the body down, they are used to treat mental illness as well as common anxiety and sleeplessness. Anti-anxiety tranquilizers are classified as a CNS depressant.
  • Antidepressants: Drugs used for the treatment of major depressive disorders and other conditions, including dysthymia, anxiety disorders, obsessive compulsive disorder, eating disorders, chronic pain, neuropathic pain and, in some cases, dysmenorrhoea, snoring, migraine, attention-deficit hyperactivity disorder (ADHD), addiction, dependence, and sleep disorders. Antidepressants are classified as a CNS depressant.
  • Attention deficit hyperactivity disorder (ADHD): A mental disorder of the neurodevelopmental type. It is characterized by problems paying attention, excessive activity, or difficulty controlling behavior which is not appropriate for a person’s age.
  • Barbiturates: Drugs that act as central nervous system depressants, and can therefore produce a wide spectrum of effects ranging from mild sedation to total anesthesia.
  • Behavioural impairment laws: This type of laws is based upon behavioural measures of impairment and police officers are required to document observed impaired behaviour that is directly linked to consumption of a specific drug. Evidence that is gathered may include observations by officers while the vehicle in motion, during contact with the driver and throughout the interaction with the driver. Drivers may be required to perform Standardized Field Sobriety Tests (SFSTs) and/or a battery of tests by a trained Drug Recognition Expert (DRE). Suspected impairment is confirmed using toxicological analysis.
  • Benzodiazepines: Benzodiazepines enhance the effect of the neurotransmitter gamma-aminobutyric acid (GABA) at the GABAA receptor, resulting in sedative, hypnotic (sleep-inducing), anxiolytic (anti-anxiety), anticonvulsant, and muscle relaxant properties. High doses of many shorter-acting benzodiazepines may also cause anterograde amnesia and dissociation. These properties make benzodiazepines useful in treating anxiety, insomnia, agitation, seizures, muscle spasms, alcohol withdrawal and as a premedication for medical or dental procedures. Benzodiazepines are categorized as either short-, intermediate-, or long-acting. Short- and intermediate-acting benzodiazepines are preferred for the treatment of insomnia; longer-acting benzodiazepines are recommended for the treatment of anxiety. Benzodiazepines are classified as a CNS depressant.
  • Blood alcohol concentration (BAC): A specific measurement of the level or concentration of alcohol in a person’s blood that is usually measured as mass per volume using the number of grams of alcohol in 100grams of blood. For example, 0.08grams of alcohol in 100 grams of blood is measured as .08.
  • Cannabinoids: Cannabinoids are a group of active compounds found in the cannabis plant. Cannabinoids act on the cannabinoid receptors in cells and alter neurotransmitter release in the brain.
  • Cannabis: The term “cannabis” refers to the cannabis plant that contains more than 100 cannabinoids. The primary psychoactive component of cannabis is delta-9-tetrahydrocannabinol, commonly known as THC. THC and its psychoactive metabolite, 11-hydroxy-THC or 11-OH-THC, and primary inactive metabolite, 11-nor-9-carboxy-THC or THC-COOH are frequently measured in biological fluids to document cannabis intake.
  • Case-control studies: A type of study that compares people with a disease or condition (‘cases’) to another group of people from the same population who do not have that disease or condition (‘controls’). A case-control study is designed to identify risks and trends, and suggest some possible causes for disease, or for particular outcomes.
  • Central nervous system depressant: This type of drug results in the physiological depression of the central nervous system that can result in decreased rate of breathing, decreased heart rate, and loss of consciousness possibly leading to coma or death. CNS depression is specifically the result of inhibited brain activity.
  • Central nervous system stimulant: These types of drugs and medicines speed up physical and mental processes.
  • Cocaethylene: Cocaethylene is the ethyl ester of benzoylecgonine. It is structurally similar to cocaine, which is the methyl ester of benzoylecgonine. Cocaethylene is formed by the liver when cocaine and ethanol coexist in the blood.
  • Cocaine: A crystalline alkaloid obtained from the coca plant that is an illicit drug in many jurisdictions. As an illicit substance, cocaine (also referred to as “coke”), is identified as a clear white powdery substance. It is commonly snorted, inhaled, or injected as a stimulant. Cocaine can also be used by medical practitioners as a form of anesthetic, however it is considered highly addictive and its use is heavily regulated.
  • Cognitive test: This type of test is an assessment of the cognitive capabilities of humans and other animals. Tests administered to humans include various forms of IQ tests; those administered to animals include the mirror test (a test of visual self-awareness) and the T maze test (which tests learning ability).
  • Community supervision: A post-conviction program that substitutes incarceration with supervised community integration. Community supervision programs can be in lieu of incarceration, in the form of probation, or as a condition of early release from incarceration as a continued part of an individual’s sentence, in the form of parole. Offenders who are granted community supervision typically pose a lower risk to public safety.
  • Controlled setting: This type of setting is controlled for the purpose of comparisons to an experimental setting in a research study. A control is a standard against which experimental observations may be evaluated. In a controlled group study, one group of participants is given an intervention, while another group (i.e., the control group) is given the standard treatment or a placebo.
  • Criminal law: The body of law that defines and prohibits conduct that is harmful to public safety and threatening to the welfare of the general population. Violators of criminal law are prosecuted through the criminal justice system and sanctions that are applied vary based upon the specific crime committed. Criminal law is generally applied when an action is harmful to individuals or public safety, as opposed to civil law which regulates the disputes between private and/or public individuals/entities.
  • Critical tracking task: This type of test is an assessment of the participants’ motor response to a visual stimulus. Participants are asked to control the position of a light bar on a display screen using a steering wheel or joystick. The instability of the bar gradually increases until the subject reaches a threshold of ability to control its position.
  • Culpability studies: This type of study allows for the comparison between a group of drivers who are at-fault versus not at-fault for a particular incident.
  • Dimethyltryptamine: A hallucinogenic drug that can be either naturally occurring or synthesized. Commonly referred to as DMT, it can be inhaled, injected, or ingested to produce hallucinogenic effects. The effects of DMT vary depending upon the specific dosage. DMT is not generally considered addicting or toxic, however it is prohibited in several jurisdictions.
  • Dissociative anesthetic: Dissociative anesthesia is a form of anesthesia characterized by catalepsy, catatonia, analgesia, and amnesia. It does not necessarily involve loss of consciousness and thus does not always imply a state of general anesthesia. Dissociative anesthetics probably produce this state by interfering with the transmission of incoming sensory signals to the cerebral cortex and by interfering with communication between different parts of the central nervous system.
  • Dose-response relationship: This measures the changes or effects in an organism when exposed to different doses of stressors of either the same substance or varying substances in combination with one another. The dose-response relationship in terms of impaired driving measures the impact of alcohol and/or drugs (the stressor) upon the individual’s (organism) driving ability. While the dose-response relation between alcohol and individuals is uniform, the dose-response between individuals and drugs is variable according to the characteristics of individuals.
  • Driving under the influence (DUI): A subset of a driving while impaired (DWI) offence in some U.S. jurisdictions. A DUI is considered a serious criminal offence whereby offenders were in clear excess of the per se limit for a specific substance or their observed behaviour conclusively demonstrates that they were impaired in their driving ability. Generally a DUI is most easily prosecuted for BAC levels that are greater than the pre-determined legal limit, usually in excess of 0.08 but in some jurisdictions the limit is 0.05.
  • Driving while ability impaired (DWAI): A subset of a driving while impaired (DWI) offence in some U.S. jurisdictions. A DWAI offence is considered a lesser offence than a DUI or DWI; however it is generally still a matter of criminal law. DWAIs are usually, although not always, charged when the BAC level is below the legal limit but drivers demonstrated driving behaviour which suggests impairment. In such cases, the onus is on police officers who observed this behaviour to provide sufficient evidence of impaired behaviour as a basis for the charge.
  • Driving while impaired (DWI): An offence whereby one’s ability to safely operate a vehicle was impaired by either alcohol or drugs in many U.S. jurisdictions. DWI offences have varying level of severity but are generally considered a matter of criminal law.
  • Drug recognition expert (DRE): A DRE is a qualified law enforcement official who is trained to recognize impairment in drivers due to drugs other than, or in addition to, alcohol. Interchangeably called a drug recognition evaluator in some jurisdictions, DRE certification requires extensive knowledge of the effects of different types of drugs on the body and officers are required to undergo extensive training prior to receiving this designation, as well as biannual certification.
  • Drug-impaired driving: The operation of a motor vehicle while under the influence of any type of psychoactive substance (illegal substances, prescription medication, over the-counter medication) or a combination of drugs and alcohol that is established or likely to impair abilities required for safe driving. It is a criminal offence and laws used to enforce this type of offence vary as behaviourial laws, per se laws, and zero tolerance laws. All are actively used throughout North American, European, and Australian jurisdictions.
  • DWI court: A specialty court that deals specifically with alcohol-impaired offences. DWI courts deal with alcohol impaired drivers exclusively whereas hybrid courts may deal with alcohol impaired driving as well as various drug offences. Courts are typically post-conviction, and the emphasis of the court is on offender accountability in tandem with rehabilitative measures. The operation and administration of these courts varies from jurisdiction to jurisdiction, and they are more resource-intensive than traditional courts. Court participants are designated high-risk and are either high-BAC or repeat impaired driving offenders.
  • Epidemiological studies: These studies examine the distribution and determinants of health events among specific populations of persons to try to determine the cause of the events.
  • Experimental studies: These types of studies keep certain variables constant while other variables are manipulated in order to determine if the observed results are directly related to the outcome of the experimental manipulations.
  • Felony offence: A serious criminal offence which is subject to long-term imprisonment in excess of one year and can also be punishable by execution in some jurisdictions. Felony offences typically cannot be expunged after any period of time and will remain on a person’s criminal record unless granted an executive pardon. Felony offence sanctions are usually applied to DWI offenders who have committed in excess of a prescribed number of lesser offences, or when they have caused serious injury and/or death.
  • Fine: A monetary fine is usually applied as the least severe sanction that can be given in response to a criminal offence. Fines can range from a few hundred dollars to several thousand dollars depending on the offence, and can be imposed in addition to other sanctions such as probation or short-term incarceration. For DWI offenders, fines are usually applied in addition to other penalties such as licence suspension or enrollment in an interlock program.
  • First offender: Persons convicted of their first criminal offence are designated first offenders. However, research shows that impaired drivers may drink and drive many times before being detected and convicted. Hence the term first offender means the first time a person has been convicted, and not necessarily the first time they committed the offence. Additionally, some jurisdictions allow first impaired driving offenders to plead to lesser traffic offences or to complete a diversion program so their conviction is expunged from their criminal record.
  • GHB: Gamma hydroxybutyrate (GHB) is a central nervous system depressant that can slow brain activity and reduce reaction time. It is colourless and odourless, often being dissolved in alcoholic beverages. GHB has been identified in some jurisdictions as a common narcotic used in instances of sexual assault where an individual is unaware there are consuming it to lessen their resistance to unwanted sexual advances. For this reason many jurisdictions have enacted strict penalties for those who distribute the drug.
  • Hallucinogen: A hallucinogen is a psychoactive agent which can cause hallucinations, perceptual anomalies, and other substantial subjective changes in thoughts, emotion, and consciousness.
  • Heroin: This opiate drug, also known as diamorphine, is often used for recreational purposes. Heroin can be injected, smoked, snorted, or inhaled. It is usually either a white or brown powdery substance. Heroin is considered highly addictive and it is heavily regulated by many states. Although it does have medical applications as a sedative, due to the addicting nature of the drug it is rare that it will be used for this purpose.
  • Hybrid Drug/DWI court: A specialty court that deals with DWI cases as a subset of drug-related offences. Hybrid courts are a combination of a drug/substance abuse court and standalone DWI courts, dealing with all manner of substance abuse-related crimes.
  • Hybrid offences: Most criminal offences in Canada are categorized as hybrid offences which mean the Crown prosecutor can decide whether the offence will be prosecuted as a summary conviction offence or an indictable offence. This decision is often based on the seriousness of the offence as well as any aggravating or mitigating factors.
  • Illicit drug use: Consumption of illegal/prohibited drugs. Common illicit drugs are cannabis, cocaine, heroin, LSD, and methamphetamine.
  • Incarceration: A state of confinement and imprisonment. Incarceration is a common criminal penalty that can be applied for summary conviction (i.e., misdemeanor) and indictable (i.e., felony) offences. For DWI offenders, incarceration can be used as a sanction for both first and repeat offenders of varying lengths depending upon the severity of the crime.
  • Indictable offences: In Canada, more serious offences are deemed indictable offences. Examples include drug trafficking, robbery, aggravated sexual assault and murder. Indictable offences typically have minimum and maximum penalties, which may include life in prison, specified as sentencing guidelines. Defendants have a right to select the mode of trial, including whether a preliminary inquiry is conducted. Convictions are appealed to the Provincial Court of Appeals.
  • Inhalant: These substances are volatile and produce chemical vapors that can be inhaled to induce a psychoactive, or mind-altering effect.
  • Jail: Short-term incarceration facilities for arrested suspects who have not been arraigned, persons awaiting a court appearance, or persons convicted of lesser charges awaiting trial or sentencing. Jails sentences can vary in length from a few days to up to over a year.
  • Ketamine: This substance produces a detachment from reality, distorting perceptions of sight and sound. Ketamine is classified as a dissociative anaesthetic.
  • Licence suspension: A type of sanction whereby an individual’s driving privilege is suspended for a period of time by the licencing authority. The reason for a licence suspension can vary as can the length of the suspension. Licence suspension is a common administrative sanction for an impaired driving offence. Licencing authorities may permit alcohol-impaired drivers to retain their driving privileges with an interlock device installed in lieu of a suspension.
  • LSD: Also known as acid, this substance is a psychedelic drug known for its psychological effects. This may include altered awareness of the surroundings, perceptions, and feelings as well as sensations and images that seem real though they are not. LSD is classified as a hallucinogen.
  • MDMA: Commonly known as ecstasy (E), this substance is a psychoactive drug used primarily as a recreational drug. Desired effects include increased empathy, euphoria, and heightened sensations. MDMA is classified as a hallucinogen.
  • Methamphetamine: A central nervous system stimulant also known as meth, ice, crystal, and chalk. Commonly used as a recreational drug for its euphoric effects, methamphetamine has limited use to treat medical conditions such as attention deficit hyperactivity disorder and obesity in the form of methamphetamine hydrochloride tablets. However this use must be prescribed. More generally, methamphetamine is recognized as a highly addictive drug and is prohibited in many jurisdictions.
  • Millilitre (ml): A unit of measurement being one thousandth of a litre.
  • Misdemeanor offence: A category of criminal offence that is less severe than a felony and may be expunged after a certain amount of time. Summary convictions are often misdemeanor offences for most jurisdictions.
  • Morphine: An opioid pain medication used to treat severe/long-term pain. Morphine is commonly used by medical professionals to help manage pain in patients who suffer from chronic conditions. It can be injected or ingested. Although it can be addictive, it is considered to be extremely safe and effective when administered n proper dosages by a health care professional.
  • Nanogram (ng): A unit of measurement being one billionth of a gram.
  • Narcolepsy: This condition is characterized by extreme drowsiness and sudden onset of sleep.
  • Narcotic analgesic: This substance mimics the activity of endorphins which are substances produced by the body to control pain.
  • New psychoactive substance: Synthetic substances that are designed to mimic the pharmacological effects of existing controlled substances.
  • Nitrates: Although nitrates are used medically, they can also be used illegally as recreational drugs and are often referred to as “poppers”. Poppers cause your veins and arteries to dilate, producing a temporary state of euphoria, relaxation, increased heart beat and a drop in blood pressure. Nitrates are classified as an inhalant.
  • Non-benzodiazepine hypnotics: A class of psychoactive drugs very similar in nature to benzodiazepines. The pharmacodynamics of non-benzodiazepine is almost entirely the same as benzodiazepine drugs and therefore employ similar benefits, side-effects, and risks. However, non-benzodiazepines have dissimilar or entirely different chemical structures and are therefore unrelated to benzodiazepines on a molecular level. Non-benzodiazepine hypnotics are classified as a CNS depressant.
  • Non-compliance: Failure to comply with or complete a criminal justice sanction imposed by a court or supervision agency. For impaired driving offenders non-compliance is usually interpreted as any action that is not in accordance an imposed sanction or condition of supervision.
  • Object movement estimation under divided attention (OMEDA): This is a computerised dual task with two parts. Part 1 allows researchers to obtain an individual’s error in time-to-collision (TTC) estimation. Different target speeds can be simulated, as can various degrees of occlusion. A secondary task is also incorporated in the form of a visual divided attention task. This requires the identification of peripheral duplication of stimuli presented centrally.
  • Opiates: Opiate drugs are derived from the poppy plant, and are therefore non-synthetic. These include opium, morphine and codeine.
  • Opioid: Opioid drugs are synthetic or semi-synthetic derived through chemical synthesis. Opioids function like opiates, and have the same pain-killing effects. Opioids are classified under the narcotic analgesic category.
  • Parole: A post-conviction form of community supervision. Parole is granted to offenders as an early release provision, usually upon the merits of good behaviour and compliance with their previous sanctions. Parole is strictly a post-release supervision program which is granted after serving a longer period of incarceration and is monitored by parole officers. The conditions of parole are generally similar to probation.
  • Passive exposure: Individuals are unintentionally exposed to traceable amounts of drugs or drug residue even though they did not directly consume, ingest, or inhale a drug. For example, persons who inhale cannabis smoke from cigarettes smoked by other individuals in their presence may have detectable levels of THC in their blood despite the fact they have not directly smoked it. The traceable amount of drug is very low.
  • Per se laws: A type of law that makes an act inherently illegal. Alcohol-impaired driving offences often utilize a per se threshold of .08 or .05 grams of alcohol in 100 grams of blood. The presence of alcohol in excess of this limit constitutes an offence which may be proven by demonstrating the driver had a BAC of .08 or greater.
  • Phencyclidine: This substance is used recreationally to produce a feeling of detachment from reality, and can induce hallucinations, anxiety and paranoia. This drug is often referred to as PCP or “angel dust” and is classified as a dissociative anaesthetic.
  • Placebo: A substance or treatment with no active therapeutic effect.
  • Plate impoundment: A form of sanction whereby the licence plate of a vehicle is seized by law enforcement, on behalf of the driver licencing agency in order to prevent an individual from driving. Plate impoundment is viewed as a cost-effective alternative to vehicle impoundment.
  • Post-conviction program: A penalty or program that is imposed upon conviction for an offence.
  • Prevalence: In criminology prevalence can be understood here to mean how often or how frequently a behaviour is committed (i.e. how many people are deterred from offending).
  • Prison: Long-term incarceration facilities which house offenders convicted of serious offences and who received a term of incarceration in excess of two years. A prison sentence may be served in provincial/state or federal facilities managed by a government department or a private prison under contract with the government agency.
  • Probation: A post-conviction program of community supervision involves the supervision of the behaviour of a convicted offender, deemed to be a low risk or moderate risk to public safety. Probation is usually in lieu of incarceration and is used for less serious offences. Probation officers function similar to parole officers.
  • Psilocybin: A hallucinogenic crystalline solid drug that is naturally occurring in 200 species of mushrooms. It has been used for religious/spiritual purposes by many different cultures due to its perception-altering effects on the individual. In general, the effects include euphoria, visual and mental hallucinations, changes in perception, a distorted sense of time, and spiritual experiences, and can include possible adverse reactions such as nausea and panic attacks. Its use is highly regulated and often prohibited in many jurisdictions. Psilocybin is classified as a hallucinogen.
  • Psychomotor: This term refers to the origination of movement in conscious mental activity. Psychomotor learning is demonstrated by physical skills such as movement, coordination, manipulation, dexterity, grace, strength, speed; actions which demonstrate fine motor skills such as use of precision instruments or tools.
  • Quaalude: Also known as methaqualone, is a non-barbiturate sedative-hypnotic substance which can be used to induce sleep but is also widely used as an illicit drug for recreational purposes. Due to health problems associated with overdoses, such as cardiac arrest, the use of Quaalude is highly regulated in many jurisdictions.
  • Recidivism: The commission of additional criminal offences following a first conviction. Recidivism rates are a standard outcome measure in the criminal justice system and in criminal justice research. High recidivism rates are usually an indicator that sanctions are not deterring offending behaviour or that the underlying problems which contribute to offending behaviour are not being addressed.
  • Repeat offenders: Persons convicted of any criminal offence more than once. Repeat offenders can be convicted of one or more offences as part of separate incidents. These offences may be similar in nature or different. For example, a repeat impaired driving offender is someone who has more than one conviction for this offence.
  • Roadside drug testing (RDT): A form of driver screening conducted at the roadside by police to determine whether or not drivers are impaired by drugs. RDT is usually only one step in a process to determine impairment. Subsequent confirmatory tests of biological fluids are usually conducted by a toxicologist to verify screening results.
  • Simple reaction time test: This test involves just one stimulus, and when it appears, subjects performing the test must react with the one response required in this type of experiment.
  • Solvent: A substance that dissolves a solute (a chemically distinct liquid, solid or gas), resulting in a solution. A solvent is classified as an inhalant.
  • Standardized field sobriety test (SFST): A form of driver screening conducted at the roadside by police to determine whether drivers are impaired by alcohol and/ drugs. SFSTs are a battery of validated tests that identify impairment in drivers. Test results can be used as evidence of impairment in court proceedings.
  • Substance abuse education: Education programs that describe the impacts and health risks associated with substance abuse. Substance abuse education may be a post-conviction sanction used in addition to other sanctions to educate offenders about the risks and consequences of substance use and share strategies to prevent or reduce harmful use.
  • Substance abuse treatment: A treatment regime that is designed to help individuals abstain or reduce the harmful use of substances, and understand their behaviour. In the criminal justice system, substance abuse treatment can often be used as a sanction, in conjunction with other sanctions, to help correct offending behaviour and improve the overall health of offenders.
  • Substance abuse: The excessive or harmful use of addictive substances that can result in misuse, abuse or dependence. Substance abuse can have accompanying health and public safety issues that have lead jurisdictions to regulate the sale and consumption of specific substances and/or prohibit their use.
  • Summary conviction offences: In Canada, less serious criminal offences are deemed summary conviction offences. The maximum penalty for a summary offence is usually a $5,000 fine and/or six months in jail. Some summary offences have higher maximum sentences and in some instances a breach of a probation order may be considered a summary offence. Persons are not fingerprinted by police for summary conviction offences, and cases may be appealed to the Superior Court of the Jurisdiction.
  • Synthetic cathinones: Synthetic cathinones are a man-made chemical related to the khat plant, a shrub grown in East Africa and Arabia. Synthetic cathinones are often referred to as “bath salts”, and are consumed for their stimulant properties.
  • THC: Tetrahydrocannabinol, or more precisely its main isomer-trans-Δ⁹-tetrahydrocannabinol, is the principal psychoactive constituent of cannabis.
  • Time Wall test: Participants estimate when an occluded, moving object reaches a target point.
  • Toluene: This substance is a colorless, water-insoluble liquid with a smell that is often associated with paint thinners. Toluene is classified as an inhalant.
  • Tower of London task: This test is used in applied clinical neuropsychology to specifically assess executive functioning to detect deficits in planning, which may occur due to a variety of medical and neuropsychiatric conditions. The test consists of two boards with pegs and several beads with different colors. The examiner uses the beads and the boards to present the subject with problem-solving tasks.
  • Vehicle impoundment: A post-conviction sanction for vehicle related offences whereby the physical vehicle is confiscated by the state and held at a predetermined location. Vehicle impoundment is often seen as a last resort for DWI offenders given that it is fairly costly to collect and store offender vehicles.
  • Vigilance: This is the action or state of keeping careful watch for possible danger or difficulties.
  • Wisconsin Card Sorting task (WCST): This is a neuropsychological test of “set-shifting” (i.e., the ability to display flexibility in the face of changing schedules of reinforcement). A number of stimulus cards are presented to subjects who are told to match the cards, but are not told how to match them; however, he or she is told whether a particular match is right or wrong.
  • Young/juvenile offenders: Offenders who, at the time of their offence, were below the age of majority that legally determines adulthood. In most jurisdictions this age is 18 however in some jurisdictions it can be as high as 21.
  • Zero tolerance laws: Laws that prohibit any amount of an impairing substance in the body of a driver who is operating a vehicle.  The value may be zero or less than a preset threshold close to zero. Zero tolerance laws are a form of per se laws. For drug-impaired driving, zero tolerance laws often have limits set slightly above zero to account for prescription medication and instances of passive exposure, neither of which would likely impair individuals.