Cannabis and Driving in Older Adults.

Importance: Epidemiological studies have found that cannabis increases the risk of a motor vehicle collision. Cannabis use is increasing in older adults, but laboratory studies of the association between cannabis and driving in people aged older than 65 years are lacking. Objective: To investigate the association between cannabis, simulated driving, and concurrent blood tetrahydrocannabinol (THC) levels in older adults. Design, Setting, and Participants: Using an ecologically valid counterbalanced design, in this cohort study, regular cannabis users operated a driving simulator before, 30 minutes after, and 180 minutes after smoking their preferred legal cannabis or after resting. This study was conducted in Toronto, Canada, between March and November 2022 with no follow-up period. Data were analyzed from December 2022 to February 2023. Exposures: Most participants chose THC-dominant cannabis with a mean (SD) content of 18.74% (6.12%) THC and 1.46% (3.37%) cannabidiol (CBD). Main outcomes and measures: The primary end point was SD of lateral position (SDLP, or weaving). Secondary outcomes were mean speed (MS), maximum speed, SD of speed, and reaction time. Driving was assessed under both single-task and dual-task (distracted) conditions. Blood THC and metabolites of THC and CBD were also measured at the time of the drives. Results: A total of 31 participants (21 male [68%]; 29 White [94%], 1 Latin American [3%], and 1 mixed race [3%]; mean [SD] age, 68.7 [3.5] years), completed all study procedures. SDLP was increased and MS was decreased at 30 but not 180 minutes after smoking cannabis compared with the control condition in both the single-task (SDLP effect size [ES], 0.30; b = 1.65; 95% CI, 0.37 to 2.93; MS ES, -0.58; b = -2.46; 95% CI, -3.56 to -1.36) and dual-task (SDLP ES, 0.27; b = 1.75; 95% CI, 0.21 to 3.28; MS ES, -0.47; b = -3.15; 95% CI, -5.05 to -1.24) conditions. Blood THC levels were significantly increased at 30 minutes but not 180 minutes. Blood THC was not correlated with SDLP or MS at 30 minutes, and SDLP was not correlated with MS. Subjective ratings remained elevated for 5 hours and participants reported that they were less willing to drive at 3 hours after smoking. Conclusions and relevance: In this cohort study, the findings suggested that older drivers should exercise caution after smoking cannabis.

Impact of COVID-19 on motor vehicle injuries and fatalities in older adults in Ontario, Canada.

BACKGROUND: Older adults constitute the group most vulnerable to COVID-19 mortality. As a result, in North America and elsewhere, older adults have been strongly advised to shelter in place. Older adults also represent the fastest growing segment of licensed drivers. OBJECTIVE: We examined the change in injuries and fatalities sustained by younger and older drivers and pedestrians during the first month of the COVID-19 pandemic. We hypothesized that adults ages 80 years and over would have a proportionally larger reduction than the other drivers and pedestrians. METHODS: Using a cohort design, we compared the proportion of drivers and pedestrians involved in injuries and fatalities attributable to individuals aged 80 years and over, as recorded in the Ministry of Transportation of Ontario (Canada) database, between the 30 days prior to shelter-in-place related to the COVID-19 pandemic and the subsequent 30 days. By way of comparison, we conducted a similar comparison for younger age cohorts (16-24 years, 25-34 years, 35-54 years, 55-64 years, and 65-79 years). RESULTS: Drivers aged 80 years and over represented 21 per 1000 injuries and fatalities in the 30 days prior to March 17, 2020 (95 % CI: 15-29), and 8 per 1000 injuries and fatalities in the 30 days beginning on that date (95 % CI: 2-20), a 64.7 % reduction (exp (ß) post 0.353, 95 % CI 0.105-0.892). Drivers in the 35-54 year age range underwent a significant but smaller reduction of 22.9 %; no significant changes were seen for drivers in other age groups, or for pedestrians of any age. CONCLUSIONS AND RELEVANCE: The physical distancing measures that aimed to reduce the spread of COVID-19 resulted in a marked reduction in driver injuries and fatalities in the oldest old, illustrating the impact of physical distancing recommendations in this population. The excess mortality burden faced by the oldest adults during the COVID-19 pandemic, by direct exposure to the virus, may be indirectly mitigated by the reduction in road-related deaths in this cohort.

Impact of medical fitness to drive policies in preventing property damage, injury, and death from motor vehicle collisions in Ontario, Canada.

INTRODUCTION: Drivers with medical conditions and functional impairments are at increased collision risk. A challenge lies in identifying the point at which such risk becomes unacceptable to society and requires mitigating measures. This study models the road safety impact of medical fitness-to-drive policy in Ontario. METHOD: Using data from 2005 to 2014, we estimated the losses to road safety incurred during the time medically-at-risk drivers were under review, as well as the savings to road safety accrued as a result of licensing decisions made after the review process. RESULTS: While under review, drivers with medical conditions had an age- and sex-standardized collision rate no different from the general driver population, suggesting no road safety losses occurred (RR = 1.02; 95% CI: 0.93-1.12). Licensing decisions were estimated to have subsequently prevented 1,211 (95% CI: 780-1,730) collisions, indicating net road safety savings resulting from medical fitness to drive policies. However, more collisions occurred than were prevented for drivers with musculoskeletal disorders, sleep apnea, and diabetes. We theorize on these findings and discuss its multiple implications. CONCLUSIONS: Minimizing the impact of medical conditions on collision occurrence requires robust policies that balance fairness and safety. It is dependent on efforts by academic researchers (who study fitness to drive); policymakers (who set driver medical standards); licensing authorities (who make licensing decisions under such standards); and clinicians (who counsel patients on their driving risk and liaise with licensing authorities). Practical Applications: Further efforts are needed to improve understanding of the effects of medical conditions on collision risk, especially for the identified conditions and combinations of conditions. Results reinforce the value of optimizing the processes by which information is solicited from physicians in order to better assess the functional impact of drivers' medical conditions on driving and to take suitable licensing action.

Update on the Risk of Motor Vehicle Collision or Driving Impairment with Dementia: A Collaborative International Systematic Review and Meta-Analysis.

Guidelines that physicians use to assess fitness to drive for dementia are limited in their currency, applicability, and rigor of development. Therefore, we performed a systematic review to determine the risk of motor vehicle collisions (MVCs) or driving impairment caused by dementia, in order to update international guidelines on driving with dementia. Seven literature databases (MEDLINE, CINAHL, Embase, etc.) were searched for all research studies published after 2004 containing participants with mild, moderate, or severe dementia. From the retrieved 12,860 search results, we included nine studies in this analysis, involving 378 participants with dementia and 416 healthy controls. Two studies reported on self-/informant-reported MVC risk, one revealing a four-fold increase in MVCs per 1,000 miles driven per week in 3 years prior, and the other showing no statistically significant increase over the same time span. We found medium to large effects of dementia on driving abilities in six of the seven recent studies that examined driving impairment. We also found that persons with dementia were much more likely to fail a road test than healthy controls (RR: 10.77, 95% CI: 3.00-38.62, z = 3.65, p < 0.001), with no significant heterogeneity (χ2 = 1.50, p = 0.68, I2 = 0%) in a pooled analysis of four studies. Although the limited data regarding MVCs are equivocal, even mild stages of dementia place patients at a substantially higher risk of failing a performance-based road test and of demonstrating impaired driving abilities on the road.

Program design for incentivizing ignition interlock installation for alcohol-impaired drivers: The Ontario approach.

INTRODUCTION: Drinking and driving is a major risk factor for traffic injuries. Although ignition interlocks reduce drinking and driving while installed, several issues undermine their implementation including delayed eligibility for installation, low installation once eligible, and a return to previous risk levels after de-installation. The Canadian province of Ontario introduced a "Reduced Suspension with Ignition Interlock Conduct Review" Program, significantly changing pre-existing interlock policy. The Program incentivizes interlock installation and an "early" guilty plea. It also attempts to reduce long-term recidivism through behavioural feedback and compliance-based removal. This evaluation is the first in assessing Program impact. METHODS: Ontario drivers with a first time alcohol-impaired driving conviction between July 1, 2005 and November 25, 2014 comprised the study cohort. Longitudinal analyses, using interrupted time series and Cox regression, were conducted in which exposure was the Program and the outcomes were ignition interlock installation (N=30,200), pre-trial elapsed time (N=30,200), and post-interlock recidivism (N=9326). RESULTS: After Program implementation, installation rates increased by 54% and pre-trial elapsed time decreased by 146 days. Results suggest no effect on post-interlock recidivism. CONCLUSIONS: Through an incentive-based design, this Program was effective at addressing two commonly cited barriers to interlock implementation- delayed eligibility for installation and low installation once eligible. Results reveal that installation rates are responsive not only to incentivization but also to other external factors, thus presenting an opportunity for policy makers to find unique ways to influence interlock uptake, and thereby, to extend their deterrent effects to a larger subset of the population. This study is one of the few that do not rely on proxy measures of installation rate.

Vehicle impoundments improve drinking and driving licence suspension outcomes: Large-scale evidence from Ontario.

Although vehicle impoundment has become a common sanction for various driving offences, large-scale evaluations of its effectiveness in preventing drinking and driving recidivism are almost non-existent in the peer-reviewed literature. One reason is that impoundment programs have typically been introduced simultaneously with other countermeasures, rendering it difficult to disentangle any observed effects. Previous studies of impoundment effectiveness conducted when such programs were implemented in isolation have typically been restricted to small jurisdictions, making high-quality evaluation difficult. In contrast, Ontario's "long-term" and "seven-day" impoundment programs were implemented in relative isolation, but with tight relationships to already existing drinking and driving suspensions. In this work, we used offence data produced by Ontario's population of over 9 million licensed drivers to perform interrupted time series analysis on drinking and driving recidivism and on rates of driving while suspended for drinking and driving. Our results demonstrate two key findings: (1) impoundment, or its threat, improves compliance with drinking and driving licence suspensions; and (2) addition of impoundment to suspension reduces drinking and driving recidivism, possibly through enhanced suspension compliance.

Evaluation of the general deterrence capacity of recently implemented (2009-2010) low and Zero BAC requirements for drivers in Ontario.

The number of injuries and fatalities associated with drinking and driving continues to decline in the province of Ontario. However, this behavior remains as one of the major contributors to collision-related injuries and fatalities. Few large-scale studies of blood alcohol concentration (BAC) <0.08% limits exist in the literature, necessitating additional investigation. Here we evaluate the general deterrent effectiveness of three Ontario countermeasures implemented during 2009 and 2010, two of which impose lower allowable BAC on drivers in the province. Using ARIMA-based interrupted time-series analysis we found that Warn-range sanctions, which include immediate roadside suspension for the previously un-targeted BAC range of 0.05-0.08%, were associated with a 17% decrease in the number of people injured or killed in drinking and driving collisions (relative to the number injured or killed in other collisions). Similarly, we found that Zero BAC requirements newly applied to young drivers (<22y.o.) were associated with a reduction in the numbers of two other dissimilar drinking and driving sanctions received by young drivers (relative to the number of these sanctions received by non-young drivers). A roadside seven-day vehicle impoundment for BAC>0.08%, which was added to an already existing roadside 90-day license suspension, was not found to produce general deterrence. Taken together, our results suggest that sanctions which target previously untargeted groups, specifically via lower BAC requirements, are effective as general deterrents against drinking and driving.

Working in tandem: The contribution of remedial programs and roadside licence suspensions to drinking and driving deterrence in Ontario.

In 1998, Ontario implemented a remedial program called "Back On Track" (BOT) for individuals convicted of alcohol-impaired driving. Drivers convicted before October 2000 were exposed to a single-component program ("Edu BOT"); those convicted after participated in a multi-component program ("Full BOT"). We evaluated the impact of BOT, and the preceding 90-day roadside licence suspension, on drinking and driving recidivism, an outcome yet to be examined, using population-wide driver records. A Chi Square Test was used to compare the three-year cumulative incidence of recidivism between three historically-defined cohorts: No BOT, Edu BOT, and Full BOT. Stratified analyses by completion status and by age were also conducted. Analyses of the roadside suspension were conducted using an interrupted time series approach based on segmented Poisson/negative binomial regression. The roadside suspension was associated with a 65.2% reduction in drinking driving recidivism. In combination with indefinite suspensions for non-completion, the BOT program was also associated with a 21% decrease in drinking and driving recidivism in the three years following a CCC driving prohibition, from 8.5% to 6.7%. This reduction cannot be explained by pre-existing trends in recidivism. Conversion of the BOT program from the single-component version to the multi-component program further reduced the three-year cumulative incidence of recidivism to 5.5% (a total reduction of 35% from pre-BOT). Results provide strong converging evidence that remedial alcohol education/treatment programs in combination with other sanctions can produce substantial increases in road safety.

Road safety impact of Ontario street racing and stunt driving law.

OBJECTIVE: The purpose of this study was to conduct a process and outcome evaluation of the deterrent impact of Ontario's street racing and stunt driving legislation which came into effect on September 30, 2007, on collision casualties defined as injuries and fatalities. It was hypothesized that because males, especially young ones, are much more likely to engage in speeding, street racing and stunt driving, the new law would have more impact in reducing speeding-related collision casualties in males when compared to females. METHODS: Interrupted time series analysis with ARIMA modelling was applied to the monthly speeding-related collision casualties in Ontario for the period of January 1, 2002 to December 31, 2010, separately for young male drivers 16-25 years of age (primary intervention group), mature male drivers 26-65 years of age (secondary intervention group), young female drivers 16-25 years of age (primary comparison group) and mature female drivers 26-65 years of age (secondary comparison group). A covariate adjustment using non-speeding casualties was included. RESULTS: A significant intervention effect was found for young male drivers with, on average, 58 fewer collision casualties per month, but not for mature male drivers, when non-speeding casualties were controlled for. No corresponding effect was observed in either comparison (females) group. CONCLUSION: These findings indicate a reduction in speeding-related casualties among young males of 58 fewer casualties per month subsequent to the introduction of Ontario's street racing and stunt driving legislation and suggest the presence of a general deterrent effect.

Evaluation of deterrent impact of Ontario's Street Racing and Stunt Driving Law on extreme speeding convictions.

OBJECTIVE: The purpose of this study was to conduct a process and outcome evaluation of the deterrent impact of Ontario's street racing and stunt driving legislation, introduced in September 2007, on extreme speeding convictions. It was hypothesized that because males are much more likely to engage in speeding, street racing, and stunt driving, the new law would have more impact in reducing extreme speeding in males compared to females. METHODS: Descriptive statistics and time series plots were used for the suspensions data. Interrupted time series analysis with autoregressive integrated moving average (ARIMA) modeling was applied to the monthly extreme speeding convictions in Ontario for the period of January 1, 2003, to December 31, 2011, to assess the impact of the new legislation, separately for male drivers (intervention group) and female drivers (comparison group). RESULTS: The results indicated that per licensed driver, 1.21 percent of 16- to 24-year-old male drivers and 0.37 percent of 25- to 64-year-old male drivers had their licenses suspended between September 2007 and December 2011. This is in contrast to female drivers: 0.21 percent of 16- to 24-year-old female drivers and 0.07 percent of 25- to 64-year-old female drivers had their licenses suspended during the same time period. A significant intervention effect of reduced extreme speeding convictions was found in the male driver group, though no corresponding effect was observed in the female driver group. The findings of this study are consistent with previous research on demographics of street racers and stunt drivers. CONCLUSIONS: These findings are congruent with deterrence theory that certain, swift, and severe sanctions can deter risky driving behavior and support the hypothesis that legal sanctions can have an impact on the extreme speeding convictions of the intervention group.