Driving under the influence of cannabis versus alcohol: A mixed-methods study examining perceptions and related risk behaviors among US and Israeli adults

BACKGROUND

Despite the dangers of driving under the influence (DUI), little is known about DUI substance-specific risk perceptions or risk factors for riding with drunk/drugged drivers (RDD).

METHODS

In this sequential exploratory mixed-methods study, we conducted: 1) multivariable analyses of cross-sectional survey data from 2222 US and Israeli adults to identify correlates of perceived cannabis- vs. alcohol-related DUI risks (linear regression) and past-month RDD involving alcohol-only, cannabis-only, or both (alcohol-cannabis) (multinomial logistic regression); and 2) deductive-inductive thematic analyses of qualitative interview data from 84 participants to identify themes elaborating on survey findings regarding DUI-related risk perceptions.

RESULTS

54.0 % reported past-month alcohol use, 16.7 % cannabis use, 4.2 % alcohol-only RDD, 5.5 % cannabis-only RDD, and 7.9 % alcohol-cannabis RDD. Being from the US, not having children at home, and cannabis non-use correlated with lower perceived cannabis vs. alcohol DUI risk. Lower perceived cannabis vs. alcohol DUI risk correlated with cannabis-only and alcohol-cannabis (vs. no) RDD, and with alcohol-cannabis (vs. cannabis-only) RDD. Alcohol use correlated with alcohol-only (vs. no) RDD and alcohol-cannabis (vs. cannabis-only) RDD. Cannabis use correlated with cannabis-only and alcohol-cannabis (vs. no) RDD, and with alcohol-cannabis (vs. alcohol-only) RDD. Being from the US correlated with alcohol-only (vs. alcohol-cannabis and none) RDD and cannabis-only (vs. alcohol-cannabis) RDD; being from Israel correlated with alcohol-cannabis (vs. no) RDD. Qualitative data indicated most participants perceived greater risk of DUI of alcohol vs. cannabis and desired more effective DUI-related prevention and regulatory efforts.

CONCLUSIONS

Prevention interventions targeting DUI- and RDD-related risk perceptions are needed, particularly for high-risk populations.

Assessment of efficacy of drug evaluation and classification program in Florida

OBJECTIVE

The present study aims to assess the effectiveness of the Drug Evaluation and Classification (DEC) program in Florida.

METHODS

Data from 236 completed DEC evaluations of central nervous system (CNS) depressants, CNS stimulants, narcotic analgesics, and cannabis were analyzed using a classification process comprising toxicology findings and corresponding Drug Recognition Expert (DRE) opinions. A series of standard measures (sensitivity, specificity, false-alarm rate, miss rate, corroboration, and accuracy) were calculated to assess the effectiveness of the DEC program.

RESULTS

DREs provided 172 correct opinions and 23 missed opinions, resulting in an accuracy rate of 88%, sensitivity rate of 97%, specificity rate of 23%, false alarm rate of 77%, miss rate of 3%, and corroboration rate of 91%. The 12-step DRE protocol of the DEC program therefore has the desired effect of DREs formulating correct opinions. The specificity and false alarm rate were influenced by the restricted testing procedures in the state of Florida. In general, law enforcement officers certified in the DEC program with specialized training can identify drugged drivers and the correct drug category of the drug causing impairment at the time of operating a vehicle. The DEC program goals are met through rigorous training and a curriculum establishing the 12-step DRE protocol.

CONCLUSIONS

DRE drug classification opinions identify drugged drivers. The limitations of Florida's biological sample testing procedures have an impact on the specificity of DRE opinions. Addressing these limitations could increase the confirmation rates of the presence of drugs in the individual's biological samples, which would directly impact the conviction rates in DUI-related criminal cases. Further Florida's testing procedures need to be further studied and updated to improve the DEC program in Florida.

adolescents, 2016-2019, USA

INTRODUCTION

Drugged driving, the operation of a vehicle under the influence of any illegal drugs and alcohol, is a growing problem, but remains understudied among adolescents. The purpose of this article is to estimate past-year driving under the influence of alcohol, marijuana, and other drugs among a large sample of U.S. adolescents and potential associations (e.g., age, race, metropolitan status, sex).

DESIGN

A cross-sectional secondary data analysis of the 2016-2019 National Survey on Drug Use and Health among 17,520 adolescents ages 16-17-years old was conducted. Weighted logistic regression models were built to determine potential associations to drugged driving.

RESULTS

An estimated 2.00% of adolescents drove under the influence of alcohol in the past year, 5.65% drove under the influence of marijuana in the past year, and an estimated 0.48% drove under the influence of other drugs other than marijuana in the past year. Differences were based on race, past-year drug use, and county status.

CONCLUSIONS

Drugged driving is a growing problem among adolescents and interventions are greatly needed to mitigate these behaviors among youth.

Reporting of unknown drug test results in the Fatality Analysis Reporting System and associated factors, 2000-2020

OBJECTIVE

To investigate how the percentage of unknown drug test results among drug-tested drivers in the Fatality Analysis Reporting System (FARS) has trended over the past 2 decades and to evaluate factors that may affect a drug-tested driver having unknown test results in FARS.

METHODS

The percentage of unknown test results among fatally injured drivers who were tested for drugs in FARS was assessed from 2000 to 2020. Trends in annual FARS drug testing data were compared with those for alcohol testing. In addition, the percentage of unknown drug test results was regressed on several factors that have been shown to be associated with higher risk of drug-involved crash fatalities.

RESULTS

The percentage of unknown drug test results in FARS has decreased drastically over the past 2 decades, and the percentage of unknown drug test data gradually matched that of alcohol data over the study period. Multiple factors such as the fatally injured drivers' age and whether the crash occurred in an urban/rural area were found to be statistically significantly associated with the percentage of unknown drug test results in FARS.

CONCLUSIONS

The percentage of unknown test results in FARS drug data is decreasing, and the significant associated factors found in this study may help identify additional strategies for reducing unknown drug test results. Future research should focus on continued improvement of FARS data, given the importance of FARS in understanding fatal crashes and informing strategies for prevention of crash-related injuries and fatalities in the United States.

A systematic review of factors associated with illegal drug driving

Drug driving is a serious problem worldwide that can increase the risk of road crashes. This systematic review seeks to identify factors associated with drug driving (i.e., driving after consuming drugs other than alcohol) to highlight gaps in existing knowledge and inform the design of more effective countermeasures. A search of the literature was conducted for the period January 1, 2005 to July 31, 2021 using six different databases. The search protocol followed PRISMA guidelines and was registered in PROSPERO (#CRD42021234616). Studies that met inclusion criteria compared drug drivers with either non-drug drivers, alcohol-only drivers or drug drivers from an earlier time period, to identify factors specifically associated with drug driving, rather than common to all drivers. Two hundred and nineteen publications met the inclusion criteria and were included within the review. Based on the findings, a logic model was developed that presents the factors associated with drug driving. Various sociodemographic, psychosocial and legal factors emerged as the main factors associated with illegal drug driving. At the sociodemographic and psychological levels, drug drivers were more likely to be single, young males who often drive after using cannabis and who score high on sensation-seeking and impulsivity scales. The key social factor found to be associated with drug driving was peer acceptance/disapproval of the behaviour. At the legal level, the review suggested that the effectiveness of current enforcement approaches to drug driving vary among jurisdictions around the world due to differences in the level of perceived certainty of apprehension and the chances of punishment avoidance. Future research into the anticipated and actual rewards for drug driving is needed to inform the development of more effective countermeasures.

The impact of COVID-19 on road safety in Canada and the United States

The COVID-19 pandemic has led to the implementation of unprecedented public health measures. The effect of these lockdown measures on road safety remain to be fully understood, however preliminary data shows reductions in traffic volume and increases in risky driving behaviors. The objective of the present study is to compare self-reported risky driving behaviors (speeding, distracted driving, drinking and driving, and drugged driving) during the pandemic in Canada and the U.S. to determine what differences exist between these two countries. Data was collected using the Road Safety Monitor (RSM), an annual online public opinion survey that investigates key road safety issues, administered to a representative sample of N = 1,500 Canadian drivers and N = 1,501 U.S. drivers. Respondents were asked about the likelihood of engaging in risky driving during the pandemic as compared to before COVID-19. Results show the majority of respondents indicated their behavior did not change, and most positively, a small proportion reported they were less likely to engage in these risky driving behaviors. However, notable proportions indicated they were more likely to engage in risky driving behaviors during the pandemic, as compared to before COVID-19. Of those who indicated this, U.S. drivers had significantly higher percentages compared to their Canadian counterparts. Behaviors most often reported by this sub-section of drivers who admit to being more likely to engage in risky driving during the pandemic were speeding (7.6%) and drinking and driving (7.6%) in the U.S., and speeding (5.5%) and distracted driving (4.2%) in Canada. Logistic regression results confirm that country was a significant factor, as U.S. drivers had greater odds of reporting they were more likely to engage in these risky driving behaviors, with the exception of speeding. Age also had a significant effect, as increasing age was associated with lower odds of reporting that these risky driving behaviors were more likely during the pandemic. Conversely, sex did not have a significant effect. Overall, the current findings suggest that a small proportion of drivers reported being more likely to engage in risky driving behaviors and the pandemic may have led to changes in the profiles of those drivers engaging in risky driving behaviors during lockdown measures. These results have important implications for policies and can inform how to manage road safety during future lockdowns.

Cannabis and crash risk among older drivers

The purpose of this research was to reanalyze data collected from the National Highway Traffic Safety Administration's Drug and Alcohol Crash Risk Study to investigate whether driving under the influence of cannabis (THC-positive) was associated with elevated crash risk for younger and older drivers. The data came from a case-control relative risk study collected from Virginia Beach, VA, over a 20-month period. Data collectors gathered driver information from the scene of vehicle crashes and, in some cases, from hospitals. Non-crash controls were sampled from the same locations, days, and times as crashes. Key data items included driver demographics and oral fluid and blood samples, which were assayed for licit and illicit drugs. We found no overall association between cannabis use and risk of crash involvement. However, when age and age² were allowed to interact with THC, significant interaction effects emerged. THC was associated with increased risk of crash involvement for older drivers. Difference between THC-positive and sober drivers emerged as significant at age 64. The research underscores the value of examining drugged driving in the context of driver age. Age-related declines in neurocognitive and psychomotor functioning were not measured but might be important in explaining the results.

Acute administration of oxycodone, alcohol, and their combination on simulated driving-preliminary outcomes in healthy adults

RATIONALE

Epidemiological data indicate that drivers testing positive for an opioid drug are twice as likely to cause a fatal car crash; however, there are limited controlled data available.

OBJECTIVES

The primary aim of this study was to assess the effects of a therapeutic dose range of oxycodone alone and in combination with alcohol on simulated driving performance.

METHODS

Healthy participants (n = 10) completed this within-subject, double-blind, placebo-controlled, randomized outpatient study. Six 7-h sessions were completed during which oxycodone (0, 5, 10 mg, p.o.) was administered 30 min before alcohol (0, 0.8 g/kg (15% less for women), p.o.) for a total of 6 test conditions. Driving assessments and participant-, observer-rated, psychomotor and physiological measures were collected in regular intervals before and after drug administration.

RESULTS

Oxycodone alone (5, 10 mg) did not produce any changes in driving outcomes or psychomotor task performance, relative to placebo (p > 0.05); however, 10 mg oxycodone produced increases in an array of subjective ratings, including sedation and impairment (p < 0.05). Alcohol alone produced driving impairment (e.g., decreased lateral control) (p < 0.05); however, oxycodone did not potentiate alcohol-related driving or subjective effects.

CONCLUSIONS

These preliminary data suggest that acute doses of oxycodone (5, 10 mg) do not significantly impair acuity on laboratory-based simulated driving models; however, 10 mg oxycodone produced increases in self-reported outcomes that are not compatible with safe driving behavior (e.g., sedation, impairment). Additional controlled research is needed to determine how opioid misuse (higher doses; parenteral routes of administration) impacts driving risk.

Ride hailing app use and drunk/drugged driving among young adult nightclub patrons

OBJECTIVE

Nightclub patrons who consume alcohol and drugs in these venues would appear to be an important population to target with on-demand ride hailing app (RHA) services to reduce drunk/drugged driving (DUI). The present study is an exploratory examination of RHA use to avoid DUI behavior, as well as the perceived barriers and benefits of such RHA use, among young adult nightclub patrons in Miami who use drugs.

METHODS

Completers of a 2011-2015 randomized controlled trial of brief interventions to reduce health risk behaviors among young adult nightclub patrons were recruited to participate in a single self-administered computer-assisted interview about health risks, driving behaviors, and RHA perceptions and use. Recruitment (N = 123) began in June 2016 and ended in July 2017. Bivariable logistic regression and ANOVA models examined group differences between: (a) those who had used an RHA to avoid DUI vs. not; and (b) those who used RHAs as their primary mode of transportation to nightclubs vs. not.

RESULTS

About half were female (52.8%); median age was 29; 59.4% Hispanic, 31.7% Black, 8.1% white, 0.8% other race/ethnicity. Recent alcohol and marijuana use were almost universally endorsed, and more than half reported recent use/misuse of cocaine (72.4%), MDMA (63.4%), and prescription benzodiazepines (62.6%) and opioids (56.9%). More than 80% reported driving under the influence of alcohol and/or drugs in the past 12 months, and 17.1% experienced a DUI arrest in the prior two years. Almost two-thirds (65.9%) of participants had used an on-demand RHA to avoid DUI, but self-driving or riding in another's car were the most common (76.4%) primary modes of transportation to clubs. RHAs were the primary mode of travel to clubs for 21 (17.1%) respondents. Participants whose friends strongly disapproved of DUI were more than twice as likely to have used RHAs for this reason compared to those who had not done so. Those reporting RHA use to avoid DUI were less likely than others to have driven under the influence in the past 12 months and were somewhat more likely to endorse DUI-related risks. Those who used alternate modes of transportation were more likely than those who used RHAs as their primary mode of transportation to clubs to endorse the expense of RHAs and the lack of RHA drivers near their favorite clubs as barriers to RHA use to travel to nightclubs.

CONCLUSIONS

This novel study among a high-risk population points to the potential for on-demand RHAs to reduce DUI behaviors and arrests among young adult nightclub patrons who consume alcohol and/or drugs in the context of the club experience. Our findings point to key educational, peer support, and structural targets for intervention to increase the use of RHAs among this population, specifically, club-based incentives for increasing RHA availability and affordability. Research is needed to fully elucidate the findings of this exploratory study, including potential differences in intervention approaches depending on the location-specific public transportation options.

The Prevention of Drugged Driving: Needs, Barriers, and Self-Efficacy of Prevention Professionals

Driving under the influence of drugs (e.g., marijuana, prescription medications) is a major public health and safety concern. As a relatively understudied and growing problem, prevention strategies that address it are not as clear, well-tested, or evidence-based as those developed for preventing other risky behaviors such as drunk driving. Key components of a successful prevention of this harmful behavior are the efforts of practitioners working in the areas of substance abuse prevention and highway safety for whom drugged driving is likely a part, but not the sole focus, of their job. We surveyed 238 prevention professionals working in substance abuse prevention and highway safety from 46 states to understand their needs, barriers, and self-efficacy to prevent drugged driving in their communities. Most respondents reported needing training and resources to implement strategies related to drugged driving, particularly with regard to engaging youth and parents, if they are to address this problem effectively. The majority of respondents also reported low levels of self-efficacy for implementing a wide range of drugged driving prevention strategies. Our findings reveal that the professionals we need to feel prepared and efficacious to prevent drugged driving have generally low feelings of confidence in their ability to do so.

Alcohol and illicit substances associated with fatal crashes in Queensland: An examination of the 2011 to 2015 Coroner's findings

PROBLEM

The problem of impaired driving is well documented in the literature but is heavily dependent upon self-report studies and/or databases that do not include in-depth information about the contributing origins of fatalities.

AIM

This study aimed to conduct an in-depth analysis of Coroner's findings for all fatally injured drivers in the state of Queensland in order to explore the prevalence of alcohol and different types of illicit substances (including drug combinations) in fatal crash reports.

METHOD

A total of 701 Coroner's reports related to drivers or controllers of vehicles involved in traffic related fatalities for the period of 2011-2015 were analysed, revealing 306 controllers (43.6%) were detected with either alcohol or illegal drugs (e.g., methylamphetamine, Δ9-tetrahydrocannabinol, cocaine or MDMA) RESULTS: Alcohol was the most commonly detected substance identified with 223 cases (72.9% of the drug and alcohol sample). Illicit drug detections totalled 147 cases (48% of the drug and alcohol sample) with Δ9-tetrahydrocannabinol the most commonly detected illicit substance (109 cases; 35.6% of the drug and alcohol sample) followed by methylamphetamine (total of 63 cases; 20.6% of the drug and alcohol sample). An important theme to emerge was the prevalence of polysubstance use among fatally injured drivers, not just for alcohol and one drug type, but also multiple drug combinations. Fatality trends revealed a decrease in both non-substance and alcohol-related fatalities across the study period. However, road fatalities where an illicit substance was detected increased by approximately 57%. Males were overrepresented as a proportion of total fatalities (82.4%) and there were no significant sex or age differences regarding illicit substance related deaths. Drivers of passenger vehicles were most commonly identified in the data (66.2%), but motorcycle operators were disproportionately represented (28.1% of the total controller sample compared to 4% of vehicle registrations in Queensland) CONCLUSION: This case study analysis of fatal crashes not only confirms the ongoing problem of alcohol and driving, but also illuminates the emerging (and escalating) issue of illicit substances detected in fatally injured drivers.

Positive drug test trends in fatally-injured drivers in the United States from 2007 to 2017

Background

The last two decades have seen tremendous changes in the U.S. environment surrounding drugs. Driving under the influence of drugs is a growing public health hazard. The present study examined trends in drug involvement in fatally-injured drivers in the U.S.

Methods

Data were drawn from the 2007–2017 Fatality Analysis Reporting System. Cochran–Armitage tests were performed to assess the statistical significance of changes in the yearly prevalence of positive drug tests in fatally-injured drivers over time. In addition, analyses were stratified by sex, race, and age.

Results

The yearly prevalence of positive drug tests in fatally-injured drivers increased significantly from 20.7% in 2007 to 30.7% in 2017, with results showing a higher prevalence among males, those aged 21–44, and Whites. The gap between Blacks and Whites narrowed in 2017. There was a decline in the yearly prevalence in all age groups between 2016 and 2017, although the decrease in the 21–44 age group was much smaller than other age groups. Among drivers who tested positive for drugs, 34.6% had a blood alcohol concentration (BAC) above the threshold of per se evidence for impaired driving, and 63% had a BAC below the threshold.

Conclusions

Our results indicate that the overall yearly prevalence of fatally-injured drivers who tested positive for drugs increased significantly from 2007 to 2017, with similar results found for subgroups. Findings further highlight that drugged driving remains a public health priority, and more action is needed to stem this disturbing trend.

Predicting categories of drugs used by suspected drug-impaired drivers using the Drug Evaluation and Classification Program tests

Objective: The purpose of this study was to statistically determine which combination(s) of drug-related signs and symptoms from the Drug Evaluation and Classification (DEC) protocol best predict the drug category used by the suspected drug-impaired driver. Methods: Data from 1,512 completed DEC evaluations of suspected impaired drivers subsequently found to have ingested central nervous system (CNS) depressants, CNS stimulants, narcotic analgesics, and cannabis were analyzed using a multinomial logistic regression procedure. A set of evaluations completed on drug-free subjects was also included. The relative importance of clinical, behavioral, and observational measures in predicting drug categories responsible for impairment was also examined. Results: Thirteen drug-related indicators were found to significantly contribute to the prediction of drug category, including being under the care of a doctor or dentist, condition of the eyes, condition of the eyelids, mean pulse rate, assessment of horizontal gaze nystagmus (HGN), convergence, performance on the One Leg Stand (OLS) Test, eyelid tremors, pupil size in darkness, reaction to light, presence of visible injection sites, systolic blood pressure, and muscle tone. Indicators related to the appearance and physiological response of the eye contributed the most to the prediction of drug category, followed closely by clinical indicators and performance on the psychophysical tests. Conclusions: The findings from this study suggest that drug recognition experts (DREs) should be careful to review a set of key signs and symptoms when determining the category of drug used by suspected drug-impaired drivers. Drug use indicators related to the appearance and physiological response of the eye were found to contribute the most to the prediction of the drug category responsible for the impairment. These results could help form the basis of a core set of indicators that DREs could initially consult to form their opinion of drug influence. This in turn may enhance the validity, effectiveness, and efficiency of drug detection and identification by DREs and lead to a more effective and efficient DEC program, improved enforcement of drug-impaired driving, and greater acceptance of the DEC program by the courts.

Multiple imputation of missing marijuana data in the Fatality Analysis Reporting System using a Bayesian multilevel model

BACKGROUND

The Fatality Analysis Reporting System (FARS) provides important data for studying the role of marijuana in motor vehicle crashes. However, marijuana testing data are available for only 34% of drivers in the FARS, which represents a major barrier in the use of the data.

METHODS

We developed a multiple imputation (MI) procedure for estimating marijuana positivity among drivers with missing marijuana test results, using a Bayesian multilevel model that allows a nonlinear association with blood alcohol concentrations (BACs), accounts for correlations among drivers in the same states, and includes both individual-level and state-level covariates. We generated 10 imputations for the missing marijuana-testing data using Markov chain Monte Carlo simulations and estimated positivity rates of marijuana in the nation and each state.

RESULTS

Drivers who were at older age, female, using seatbelt at the time of crash, having valid license, or operating median/heavy trucks were less likely to test positive for marijuana. There was a reverse U-shaped association between BACs and positivity of marijuana, with lower positivity when BACs < 0.01 g/dL or ≥0.15 g/dL. The MI data estimated a lower positivity rate of marijuana in the nation and each of the state than the observed data, with a national positivity rate of 11.7% (95% CI: 11.1, 12.4) versus 14.8% using the observed data in 2013.

CONCLUSIONS

Our MI procedure appears to be a valid approach to addressing missing marijuana data in the FARS and may help strengthen the capacity of the FARS for monitoring the epidemic of drugged driving and understanding the role of marijuana in fatal motor vehicle crashes in the United States.

Ability to monitor driving under the influence of marijuana among non-fatal motor-vehicle crashes: An evaluation of the Colorado electronic accident reporting system

INTRODUCTION

As more states legalize medical/recreational marijuana use, it is important to determine if state motor-vehicle surveillance systems can effectively monitor and track driving under the influence (DUI) of marijuana. This study assessed Colorado's Department of Revenue motor-vehicle crash data system, Electronic Accident Reporting System (EARS), to monitor non-fatal crashes involving driving under the influence (DUI) of marijuana.

METHODS

Centers for Disease Control and Prevention guidelines on surveillance system evaluation were used to assess EARS' usefulness, flexibility, timeliness, simplicity, acceptability, and data quality. We assessed system components, interviewed key stakeholders, and analyzed completeness of Colorado statewide 2014 motor-vehicle crash records.

RESULTS

EARS contains timely and complete data, but does not effectively monitor non-fatal motor-vehicle crashes related to DUI of marijuana. Information on biological sample type collected from drivers and toxicology results were not recorded into EARS; however, EARS is a flexible system that can incorporate new data without increasing surveillance system burden.

CONCLUSIONS

States, including Colorado, could consider standardization of drug testing and mandatory reporting policies for drivers involved in motor-vehicle crashes and proactively address the narrow window of time for sample collection to improve DUI of marijuana surveillance. Practical applications: The evaluation of state motor-vehicle crash systems' ability to capture crashes involving drug impaired driving (DUID) is a critical first step for identifying frequency and risk factors for crashes related to DUID.

Evaluation of three rapid oral fluid test devices on the screening of multiple drugs of abuse including ketamine

Rapid oral fluid testing (ROFT) devices have been extensively evaluated for their ability to detect common drugs of abuse; however, the performance of such devices on simultaneous screening for ketamine has been scarcely investigated. The present study evaluated three ROFT devices (DrugWipe^® 6S, Ora-Check^® and SalivaScreen^®) on the detection of ketamine, opiates, methamphetamine, cannabis, cocaine and MDMA. A liquid chromatography tandem mass spectrometry (LCMS) assay was firstly established and validated for confirmation analysis of the six types of drugs and/or their metabolites. In the field test, the three ROFT devices were tested on subjects recruited from substance abuse clinics/rehabilitation centre. Oral fluid was also collected using Quantisal^® for confirmation analysis. A total of 549 samples were collected in the study. LCMS analysis on 491 samples revealed the following drugs: codeine (55%), morphine (49%), heroin (40%), methamphetamine (35%), THC (8%), ketamine (4%) and cocaine (2%). No MDMA-positive cases were observed. Results showed that the overall specificity and accuracy were satisfactory and met the DRUID standard of >80% for all 3 devices. Ora-Check^® had poor sensitivities (ketamine 36%, methamphetamine 63%, opiates 53%, cocaine 60%, THC 0%). DrugWipe^® 6S showed good sensitivities in the methamphetamine (83%) and opiates (93%) tests but performed relatively poorly for ketamine (41%), cocaine (43%) and THC (22%). SalivaScreen^® also demonstrated good sensitivities in the methamphetamine (83%) and opiates (100%) tests, and had the highest sensitivity for ketamine (76%) and cocaine (71%); however, it failed to detect any of the 28 THC-positive cases. The test completion rate (proportion of tests completed with quality control passed) were: 52% (Ora-Check^®), 78% (SalivaScreen^®) and 99% (DrugWipe^® 6S).

A latent class analysis of poly-marijuana use among young adults

INTRODUCTION

With more states legalizing marijuana use, the marijuana industry has grown, introducing a variety of marijuana products. Our study explores the use of multiple marijuana products (poly-marijuana use) and the characteristics associated with this behavior.

METHODS

Past-month marijuana users aged 18-34years were surveyed online via an existing online panel (n=2444). Participants answered questions about past-month use of three types of marijuana (plant-based, concentrates, edibles), marijuana use patterns, and driving after use. Latent class analysis was used to identify subgroups of marijuana users.

RESULTS

Four classes of marijuana users were identified: Light plant users, who used only plant-based products infrequently and were unlikely to drive after use (32%); Heavy plant users, who used mainly plant-based products frequently, multiple times per day, and were likely to drive after use (37%); Plant and concentrates users, who used plant-based products heavily and concentrates at least infrequently, used multiple times per day, and were likely to drive after use (20%); Light plant and edibles users, who used both products infrequently and were unlikely to drive after use (10%). Those in legal marijuana states were more likely to belong to the poly-marijuana groups.

DISCUSSION

Our findings reflect the increase in popularity of new marijuana products in legal states and suggest that heavy user groups, including concentrates users, are associated with driving after use. As various forms of marijuana use increases, monitoring and surveillance of the use of multiple types of marijuana will be important for determining potential varying impacts on physiological and social consequences.

Use of prescription opioids and motor vehicle crashes: A meta analysis

OBJECTIVES

Opioid analgesics are a major driver of the ongoing opioid epidemic in the United Sates, accounting for about two thirds of drug overdose fatalities. There are conflicting reports regarding the effects of prescription opioids on driving safety. A meta-analysis was performed to assess the epidemiologic evidence for the association between use of prescription opioids and the risk of motor vehicle crashes.

METHODS

Studies examining the association between driver prescription opioid use and motor vehicle crash involvement or crash culpability and published in English were identified through a comprehensive search of 15 bibliographic databases. Eligible articles were fully reviewed and summarized. Study quality was assessed using the Newcastle-Ottawa Scale. Overall summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated through random effects models.

RESULTS

Overall, 15 studies were included in the meta-analysis; of them, 10 assessed the association of prescription opioid use with the risk of crash involvement and 5 assessed the association of prescription opioid use with the risk of crash culpability. Reported crude ORs associated with prescription opioid use ranged from 1.15 to 8.19 for the risk of crash involvement and from 0.75 to 2.78 for the risk of crash culpability. Summary ORs based on pooled data were 2.29 (95% CI: 1.51, 3.48) for crash risk and 1.47 (95% CI: 1.01, 2.13) for crash culpability.

CONCLUSIONS

The existent epidemiologic evidence indicates that use of prescription opioids by drivers is associated with significantly increased risks of crash involvement and crash culpability. Further research is needed to understand the epidemiologic patterns of prescription opioid use in the driver population and the interaction effects between opioids and alcohol on driving safety.

Continuity of drunk and drugged driving behaviors four years post-college

BACKGROUND

Driving under the influence of alcohol is a leading cause of injury and premature death among young adults, and college-educated individuals are at particularly high risk. Less is known about driving under the influence of other drugs, which is on the rise.

METHOD

This study describes prospective seven-year trends in alcohol and other drug (AOD)-involved driving among a young-adult sample beginning with their second year of college (i.e., Years 2-8), and documents the extent of continuity in such behaviors across time. Originally recruited as incoming first-year students at one large public university, participants (n=1194) were interviewed annually about how frequently they drove while drunk/intoxicated (DWI), after drinking any alcohol (DAD), and/or while under the influence of other drugs (DD). Follow-up rates were high (>75% annually).

RESULTS

Among participants with access to drive a car, annual prevalence peaked in Year 4 (modal age 21) for both DWI (24.3%_wt) and DD (19.1%_wt) and declined significantly thereafter through Year 8 (both ps<0.05). DAD was far more prevalent than DWI or DD, increasing from 40.5%_wt in Year 2 to 66.9%_wt in Year 5, and plateauing thereafter. Among marijuana-using participants, likelihood of DD was consistently greater than the likelihood of DWI among Heavy Episodic and Light-to-Moderate drinkers, and it declined significantly during Years 5-8 (p<0.05).

CONCLUSION

Post-college declines in heavy drinking and DWI prevalence were encouraging but did not necessarily translate to reductions in likelihood of engaging in DWI, depending on drinking pattern. College-educated individuals represent an important target for AOD-involved driving prevention.

Prevalence and trends of drugged driving in Canada

OBJECTIVES

This study evaluates prevalence and trends in drugged driving in Canada based on multiple indicators collected from the Road Safety Monitor (RSM) and Canada's National Fatality Database maintained by the Traffic Injury Research Foundation (TIRF). The objective of this paper is to identify the state of drug-positive driving in Canada, as well as to make comparisons with data from previous years to determine whether changes have occurred.

METHODS

Available data from the RSM on self-reported drugged driving behaviours were collected and analyzed using multivariate techniques in various years spanning from 2002 to 2015. Data from TIRF's National Fatality Database from 2000 to 2012 were also analyzed to evaluate trends and prevalence of drugs in fatally injured drivers across Canada. Additionally, differences among drugged drivers with respect to gender and age were studied.

RESULTS

Analyses of the RSM data and of the National Fatality Database showed that, as a whole, the prevalence of drugged driving has remained relatively stable over the past decade, with some changes noticed in specific years for some drug types. Specifically from the RSM, there was a 62.5% increase from the 1.6% of drivers reporting driving within two hours of using marijuana in 2013 to 2.6% in 2015. The analyses of the fatality data revealed a 16.9% increase in the percentage of fatally injured drivers testing positive for drugs between 2000 and 2012 (from 33.56% to 39.24%). Cocaine-positive fatally injured drivers increased from 3.6% in 2000 to 6.2% in 2012. Similarly, marijuana-positive fatally injured drivers increased from 12.8% in 2000 to 19.7% in 2012. Results showed varying characteristics with respect to gender and age among self-reported and fatally injured drugged drivers.

CONCLUSIONS

Drugged driving behaviours remain prevalent among Canadian drivers and drugs continue to be found in over one-third of tested fatally injured drivers. Although self-reported behaviours have neither decreased nor increased overall in the past decade according to RSM data, with the exception of driving within two hours of using marijuana, data from fatally injured drivers reveal that small, but significant increases in some behaviours have occurred.

Differences in state drug testing and reporting by driver type in U.S. fatal traffic crashes

INTRODUCTION

Driving under the influence of drugs, including marijuana, has become more prevalent in recent years despite local, state, and federal efforts to prevent such increases. The Fatality Analysis Reporting System (FARS) is the primary source of drugged driving data for fatal crashes in the United States but lacks the completeness required to calculate unbiased estimates of drug use among drivers involved in fatal crashes.

METHODS

This article uses the 2013 FARS dataset to present differences in state drug testing rates by driver type, driver fault type, and state-level factors; discusses limitations related to analysis and interpretation of drugged driving data; and offers suggestions for improvements that may enable appropriate use of FARS drug testing data in the future.

RESULTS

Results showed that state drug testing rates were highest among drivers who died at the scene of the crash (median=70.8%) and drivers who died and were at fault in the crash (median=64.4%). The lowest testing rates were seen among surviving drivers who were not transported to a hospital (median=14.0%) and surviving drivers who were not at fault in the crash (median=10.0%). Drug testing rates differed by state blood alcohol content (BAC) testing rate across all driver types and driver fault types, and in general, states that tested a higher percentage of drivers for BAC had higher drug testing rates.

DISCUSSION

Testing rates might be increased through standardization and mandatory testing policies. FARS data users should continue to be cautious about the limitations of using currently available data to quantify drugged driving. More efforts are needed to improve drug testing and reporting practices, and more research is warranted to establish drug concentration levels at which driving skills become impaired.

DUID prevalence in Colorado's DUI citations

INTRODUCTION

There are limited studies that measure the prevalence of driving under the influence of drugs (DUID) based upon impairment measures because most prevalence studies are based on drug tests. The aim of this study was to provide the first estimate of DUID prevalence in Colorado using data collected by Colorado law enforcement officers in vehicular homicide (VH) and vehicular assault (VA) cases, and reported in court records.

METHODS

The four research questions of this study were answered by completing independent t-tests or Mann-Whitney U tests, Pearson chi-square analyses or Fisher's exact tests, and Kruskal-Wallis tests.

RESULTS

Seventy percent (119 out of 170) of the cases involved alcohol only and 30% (51 out of 170) involved drugs. Of the latter cases, 32 cases involved a combination of alcohol and drugs and 19 cases identified drugs only, with no alcohol. Marijuana was the most commonly cited drug (23 cases); however, it was the sole impairing substance identified in only three cases.

CONCLUSION

Polydrug use was very common among DUID cases, which makes it difficult to identify which drug or drugs caused the impairment responsible for the Driving Under the Influence citation. This study revealed tha (a) drugged driving is a frequent cause of DUI citations in cases charged with VH or VA; (b) that polydrug use, rather than marijuana, is the most common cause of drugged driving in Colorado; and (c) that current warrant procedures render blood test results meaningless in cases of marijuana-impairment.

PRACTICAL APPLICATION

States should collect and analyze DUID data to ensure legislators focus on the right DUID problems to improve biological testing for drugs, adopt more appropriate roadside testing, and enact stronger DUID laws to protect the public.

Establishing legal limits for driving under the influence of marijuana

Marijuana has become the most commonly detected non-alcohol substance among drivers in the United States and Europe. Use of marijuana has been shown to impair driving performance and increase crash risk. Due to the lack of standardization in assessing marijuana-induced impairment and limitations of zero tolerance legislation, more jurisdictions are adopting per se laws by specifying a legal limit of Δ9-tetrahydrocannabinol (THC) at or above which drivers are prosecuted for driving under the influence of marijuana. This review examines major considerations when developing these threshold THC concentrations and specifics of legal THC limits for drivers adopted by different jurisdictions in the United States and other countries.

Changes in driver cannabinoid prevalence in 12 U.S. states after implementing medical marijuana laws

OBJECTIVE

To determine if cannabinoid prevalence increased among fatal-crash-involved drivers in 12 U.S. states after implementing medical marijuana laws.

METHODS

Time series analyses of 1992 to 2009 driver cannabinoid prevalence from the Fatality Analysis Reporting System.

RESULTS

Increased driver cannabinoid prevalence associated with implementing medical marijuana laws was detected in only three states: California, with a 2.1 percentage-point increase in the percentage of all fatal-crash-involved drivers who tested positive for cannabinoids (1.1% pre vs. 3.2% post) and a 5.7 percentage-point increase (1.8% vs. 7.5%) among fatally-injured drivers; Hawaii, with a 6.0 percentage-point increase (2.5 vs. 8.5) for all drivers and a 9.6 percentage-point increase (4.9% vs. 14.4%) among fatally-injured drivers; and Washington, with a 3.4 percentage-point increase (0.7% vs. 4.1%) for all drivers and a 4.6 percentage-point increase (1.1% vs. 5.7%) among fatally-injured drivers. Changes in prevalence were not associated with the ease of marijuana access afforded by the laws.

DISCUSSION

Increased prevalence of cannabinoids among drivers involved in fatal crashes was only detected in a minority of the states that implemented medical marijuana laws. The observed increases were one-time changes in the prevalence levels, rather than upward trends, suggesting that these laws may indeed provide marijuana access to a stable population of patients as intended, without increasing the numbers of new users over time. Although this study provides some insight into the potential impact of these laws on public safety, differences between states in drug testing practices and regularity, along with the fairly recent implementation of most medical marijuana laws, suggest that the long-term impact of these laws may not yet be known.

PRACTICAL APPLICATIONS

It is recommended that nationwide standardization of drug testing procedures and criteria be considered to improve the consistency of testing both between and within jurisdictions.

Trends in fatal motor vehicle crashes before and after marijuana commercialization in Colorado

BACKGROUND

Legal medical marijuana has been commercially available on a widespread basis in Colorado since mid-2009; however, there is a dearth of information about the impact of marijuana commercialization on impaired driving. This study examined if the proportions of drivers in a fatal motor vehicle crash who were marijuana-positive and alcohol-impaired, respectively, have changed in Colorado before and after mid-2009 and then compared changes in Colorado with 34 non-medical marijuana states (NMMS).

METHODS

Thirty-six 6-month intervals (1994-2011) from the Fatality Analysis Reporting System were used to examine temporal changes in the proportions of drivers in a fatal motor vehicle crash who were alcohol-impaired (≥0.08 g/dl) and marijuana-positive, respectively. The pre-commercial marijuana time period in Colorado was defined as 1994-June 2009 while July 2009-2011 represented the post-commercialization period.

RESULTS

In Colorado, since mid-2009 when medical marijuana became commercially available and prevalent, the trend became positive in the proportion of drivers in a fatal motor vehicle crash who were marijuana-positive (change in trend, 2.16 (0.45), p<0.0001); in contrast, no significant changes were seen in NMMS. For both Colorado and NMMS, no significant changes were seen in the proportion of drivers in a fatal motor vehicle crash who were alcohol-impaired.

CONCLUSIONS

Prevention efforts and policy changes in Colorado are needed to address this concerning trend in marijuana-positive drivers. In addition, education on the risks of marijuana-positive driving needs to be implemented.

Alcohol and drug use among young adults driving to a drinking location

BACKGROUND

Clubs that feature electronic music dance events (EMDEs) draw young adults aged 18-34 who are at high-risk for alcohol-related crashes to locations where alcohol sales are the principal source of revenue. Up to 30% of these attendees may also use drugs. This provides an important context in which to study driving arrangements that reflect concern with impaired driving. We explored whether drivers were using less alcohol and fewer drugs at exit than their passengers were and whether a driver for the group ever changed after consuming too much during the evening.

METHODS

Using biological measures of alcohol consumption (breath tests) and drug use (oral fluid tests), 175 drivers and 272 passengers were surveyed among young adults arriving at and departing from EMDEs in San Francisco.

RESULTS

Upon exit from the drinking locations, only 20% of the drivers, compared to 47% of the passengers, had a high breath alcohol concentration (defined as a BrAC of .05 g/dL or greater). Further, there was evidence that drivers with high BrACs switched to passenger status on exit and former passengers with lower BrACs replaced those drivers. However, there were no differences in the prevalence of drug use among drivers and passengers.

CONCLUSIONS

These findings suggest that the effort by young adult drivers to avoid alcohol-impaired driving appears to be reducing the number of drivers with high BrACs returning from drinking locations, such as EMDEs, by about one third. However, there is no similar pattern for drugged driving.