People Against Drink/Drug Driving

The Supreme Court is considering a case involving truck driver Douglas Horn, who was terminated after a drug test revealed THC in his system, despite using a product he believed to be THC-free. Horn has taken legal action against the product’s manufacturer, Medical Marijuana Inc., under the federal Racketeer Influenced and Corrupt Organizations Act (RICO), arguing that he suffered a business injury. During oral arguments, several justices appeared inclined to allow Horn to proceed with his claim, focusing on whether he meets the RICO requirement of being injured in business or property. The outcome could redefine how consumers seek redress against misleading product claims, particularly in the burgeoning cannabis industry.

Horn’s case originated when he began using a “wellness product” named Dixie X, advertised as containing zero THC. After failing a mandatory drug test, Horn independently verified the product did contain THC, leading to his dismissal. The court’s decision could send the case back to lower courts for further proceedings, potentially setting a precedent for similar disputes involving cannabis-related products. For additional details, visit New York Times.

The recent amendment to Victorian driving laws, set to take effect March 1, marks a significant shift in how medicinal cannabis users who test positive for THC while driving will be treated under the law. While proponents celebrate this as a victory for medical cannabis patients, serious concerns about road safety emerge from extensive research on cannabis impairment and driving ability.

Under the new legislation, magistrates will have discretionary power when dealing with drivers who test positive for THC (tetrahydrocannabinol) if they hold a valid prescription for medicinal cannabis and appear unimpaired. This changes the previous mandatory six-month licence suspension and fine system. However, driving with THC present in one’s system remains an offence.

The complexity of THC impairment presents significant challenges for road safety. Unlike alcohol, where blood alcohol concentration correlates strongly with impairment levels, THC’s effects are far more variable and complex. Research from the Colorado Department of Public Health and Environment shows that driving impairment can persist for at least six hours after smoking cannabis, even with doses as low as 18mg of THC. However, typical cannabis consumption often involves much higher doses – a standard joint containing 400mg of flower with 15% THC concentration can deliver around 60mg of THC, potentially extending impairment duration significantly.

Recent research published in Scientific Reports (2021) raises particular concern about cannabis users’ visual function and self-perception of impairment. The study found significant adverse effects on all visual parameters analysed, including visual acuity, contrast sensitivity, stereoacuity, and night-vision disturbances. Crucially, the research revealed that cannabis users may be unaware of their visual impairment, creating a dangerous situation where drivers might feel capable of driving while actually experiencing significant visual degradation.

Data from jurisdictions with longer histories of cannabis law reform provide sobering insights. Colorado’s Department of Public Safety reported that 66.3% of DUI case filings in 2018 tested positive for cannabinoids, with nearly half having THC levels at or above 5ng/mL, their legal limit. Studies from Washington State showed that cannabis-involved fatal crashes doubled after legalisation, increasing from 9% to 19%.

The Canadian perspective, detailed in research by the Traffic Injury Research Foundation, highlights how THC impairs crucial driving skills including:

• Speed control
• Lane positioning
• Reaction time
• Divided attention
• Route planning
• Decision-making
• Risk assessment

The argument that regular medicinal users develop tolerance to THC’s impairing effects is problematic. While some studies suggest partial tolerance development, research indicates that when tolerance occurs, users typically increase their dosage to achieve desired effects, potentially maintaining or even increasing impairment levels.

Furthermore, a 2024 study from Massachusetts General Hospital revealed that THC significantly disrupts the prefrontal cortex’s normal connections and activity – the brain region crucial for decision-making and self-control. This disruption was measurable and correlated with intoxication severity, potentially affecting drivers’ ability to respond to changing road conditions.

The new Victorian legislation creates a challenging situation for law enforcement. How will officers determine whether a THC-positive driver is truly unimpaired? The research consistently shows that subjective self-assessment of impairment is unreliable, with users often underestimating their level of impairment.

While the law change aims to protect legitimate medicinal cannabis users from unfair penalties, it may inadvertently create a dangerous precedent. Australia’s successful road safety record has been built on clear, evidence-based policies regarding impaired driving. Introducing subjective assessment of impairment for THC-positive drivers could compromise these standards and potentially lead to increased road safety risks.

The evidence suggests that any THC presence while driving poses potential risks to public safety, regardless of its source or legal status. As this legislative change takes effect, careful monitoring of its impact on road safety will be crucial, as will continued research into reliable methods for assessing cannabis impairment in drivers.

Dalgarno Institute

Sources

• Major change to cannabis laws for millions of Australians
• Effects of cannabis on visual function and self-perceived visual quality
• Cannabis (THC) messes with your Executive Functions – Can disrupt and impede good decision making and add to dysregulation
• Dalgarno Institute Website – ‘Medicinal’ Cannabis & Driving – Is it an Issue? (DRR)

As marijuana legalisation continues to expand across the United States, a growing concern has emerged regarding marijuana-impaired driving. Despite widespread legalisation, with 38 states approving medical use and 23 allowing recreational use as of April 2023, the challenge of addressing marijuana-impaired driving remains significant. Unlike alcohol, which has established metrics for impairment, determining marijuana’s effects on driving presents complex challenges.

Legal Landscape and Challenges

The legal framework for marijuana-impaired driving varies across states, with differing approaches to regulating THC levels—the psychoactive component in marijuana. Some states, like Ohio and Illinois, have set specific THC limits for driving, ranging between 2 and 5 nanograms per millilitre of blood. However, the effectiveness of these limits as indicators of impairment is under debate. In other states, zero tolerance laws prohibit any detectable THC level while driving.
Efforts to develop reliable testing methods for THC impairment, such as breathalysers, have been largely unsuccessful. THC’s complex behaviour in the body, coupled with its larger molecular structure compared to alcohol, complicates the creation of effective, consistent tests. Currently, blood and saliva tests are the primary methods used, though their reliability is questioned.

Public Health Implications

Marijuana is the most commonly used federally illegal drug in the U.S., with 48.2 million users in 2019, highlighting the urgent need to address marijuana-impaired driving. Researchers note that public awareness of marijuana’s potential driving hazards is lower compared to alcohol, despite evidence showing similar risks. Marijuana affects cognitive functions unpredictably, acting as a depressant, stimulant, or hallucinogen, which complicates efforts to establish clear impairment thresholds.

Statistics on Marijuana Use and Driving

The prevalence of marijuana use among drivers has increased significantly over recent years. According to toxicology reports from fatal car crashes, the number of drivers under the influence of marijuana has multiplied five to tenfold since 2000. A 2022 National Transportation Safety Board report identified marijuana and alcohol as the most detected substances among impaired drivers. Moreover, many drivers who tested positive for marijuana also had other impairing substances in their system.

Comparison with Alcohol Impairment

Unlike alcohol, where impairment levels are well-understood and regulated, marijuana’s effects on driving remain elusive. Dr. Guohua Li, an expert in epidemiology, underscores that marijuana’s impact on driving is more unpredictable than alcohol. While alcohol functions predominantly as a depressant, marijuana can affect the central nervous system in various ways, making consistent impairment measurements difficult.

Ongoing Research Efforts

Research continues to explore the relationship between marijuana use and driving impairment. A study published in JAMA Network Open highlighted a 475% increase in cannabis-related traffic injuries in Ontario, Canada, from 2010 to 2021. Although cannabis-involved traffic injuries represent a small fraction of total traffic injuries, this trend underscores the growing concern over marijuana-impaired driving.

Efforts to determine reliable THC impairment indicators remain ongoing. Current studies suggest that THC levels in bodily fluids are not reliable markers of impairment. The need for comprehensive research on marijuana’s impact on driving and the development of accurate testing methods is critical as legalisation spreads. (Source: WRD News)

Following a tragic crash that killed six high school girls in Oklahoma, the head of the U.S. National Transportation Safety Board (NTSB) is urging parents to warn their teenagers about the dangers of driving under the influence of marijuana. The NTSB has released its final report on the March 22, 2022 collision, which provides detailed insights into the causes and implications of the accident.

Background of the Crash

The collision occurred in Tishomingo, Oklahoma, involving a Chevrolet Spark hatchback and a gravel-hauling semi. The investigation revealed that the 16-year-old driver slowed for an intersection but then accelerated through a stop sign. The NTSB concluded that she was likely impaired by recent marijuana use and distracted by having five other teenagers in the car.

NTSB Findings and Recommendations

Impairment from Marijuana

The NTSB report highlights several key impairments caused by marijuana:

• Decreased Motor Coordination: Marijuana use can significantly impair motor skills necessary for driving.
• Slowed Reaction Time: Users may react more slowly in critical driving situations.
• Impaired Judgement of Time and Distance: Accurate perception of time and spatial relationships is crucial for safe driving.

Broader Concerns: Chairwoman Jennifer Homendy pointed out that the issue of cannabis impairment while driving extends beyond teenagers. With more states legalising recreational marijuana, both teens and adults tend to underestimate its risks when driving.

Legal Status of Marijuana: As of now, marijuana is legal for recreational use in 24 states and Washington, D.C., for individuals aged 21 and older. However, driving while impaired by marijuana is illegal across all states and Washington, D.C. In Oklahoma, recreational use is not permitted, although medical use is allowed.

Safety Alert and Parental Guidance: The NTSB has issued a safety alert urging parents to discuss with their children the dangers of driving under the influence of marijuana. The board emphasised the importance of educating young drivers on making responsible choices to avoid impaired driving and not riding with impaired drivers.

Broader Implications: The NTSB’s findings underscore the critical need for increased awareness and education around the risks of driving under the influence of marijuana. As legalisation expands, understanding how marijuana affects driving abilities becomes increasingly important to prevent similar tragedies.

(Source: AP News)

Trait anger as a predictor of dangerous driving behaviour amongst people who use methamphetamine

“Methamphetamine is now the most common illicit substance detected among drivers injured or killed due to road trauma in Australia

Drivers affected by (meth)amphetamine are five times more likely to be killed, and over 6-times more likely to be injured in a traffic crash; more than double the risk reported for common impairing drugs such as benzodiazepines Perhaps unsurprisingly, people who use methamphetamine are also overrepresented in road trauma incidents requiring emergency care. Amphetamine-intoxicated drivers are up to 19 times more likely to be deemed responsible (culpable) for a motor vehicle collision compared to non-drug users, and they are significantly more likely to die as a result

Despite a reduction in self-reported use (Australian Institute of Health and Welfare, 2024) objectively, methamphetamine consumption in Australia continues to rise. Consequently, Australia now has one of the highest documented rates of methamphetamine use per capita, and the highest global age-standardised prevalence of (meth)amphetamine dependence.”

Conversely, low-to-moderate doses of methamphetamine can improve select, unidimensional psychomotor skills ostensibly related to driving, such as attention and perceptual processing speed however, this limited beneficial effect appears to be extinguished (and even maladaptive) at higher doses or during complex tasks or those requiring multi-tasking .

Negative emotionality and heightened levels of aggression are a pervasive, if largely anecdotal observation of individuals who consume methamphetamine. Individuals who consume methamphetamine cite elevated levels of self-reported aggression compared to drug-free controls.

Key Take-aways

• Methamphetamine is increasingly implicated in serious road-traffic incidents.
• Examining psychosocial factors may help identify predictors of dangerous driving behaviour.
• Licensed individuals who report predominant methamphetamine use were recruited.
• Trait Anger strongly and positively predicted dangerous driving behaviour in this cohort.
• Stable negative-emotional factors may increase harm through situational reactivity.

(Source: Science Direct)