The association between single and dual use of cannabis and alcohol and driving under the influence and riding with an impaired driver in a large sample of Canadian adolescents

OBJECTIVE

Dual use of cannabis and alcohol has increased in adolescents, but limited research has examined how it relates to impaired driving or riding with an impaired driver (IDR) compared to single substance use. This study aimed to examine the odds of alcohol- and/or cannabis-IDR among adolescents based on their use of alcohol and/or cannabis, and whether associations differed by gender and age.

METHODS

Cross-sectional survey data were used from a sample of 69,621 students attending 182 Canadian secondary schools in the 2021/22 school year. Multilevel logistic regression estimated the odds of exclusive alcohol-IDR, exclusive cannabis-IDR, and both alcohol and cannabis IDR (alcohol-cannabis-IDR). Substance use interactions with gender and age were tested.

RESULTS

Overall, 14.7% of participants reported IDR; 7.5% reported exclusive alcohol-IDR, 3.2% reported exclusive cannabis-IDR, 4.0% reported alcohol-cannabis-IDR, and 7.4% were unsure if they had experienced IDR. The prevalence of IDR varied across substance use groups, 8.0% among nonuse, 21.9% among alcohol-only use, 35.9% among cannabis-only use, and 49.6% among dual use groups. Gender diverse, older, and students with lower socioeconomic status exhibited a higher likelihood of reporting alcohol-cannabis-IDR. Dual use was significantly associated with 9.5 times higher odds of alcohol-cannabis-IDR compared to alcohol-only use, and 3.0 times higher odds compared to cannabis-only use. Dual use was also associated with an increased likelihood of either alcohol- or cannabis-IDR.

CONCLUSIONS

This study highlights that all students, regardless of substance use, are at risk of IDR, but students engaged in dual use of alcohol and cannabis face an elevated risk compared to both peers who do not use substances and those who use only a single substance. These findings emphasize the importance of targeted interventions that address the risks associated with IDR.

Examining the impact of legalization on the prevalence of driving after using cannabis: A comparison of rural and non-rural parts of Canada

OBJECTIVE

The purpose of this study was to examine the likelihood of driving after using cannabis, and of being a passenger with someone who is driving after using cannabis, in rural areas and non-rural areas before and after legalization.

METHODS

A multi-wave analysis of Canada's National Cannabis Survey was conducted using logistic regression with interactions to predict the prevalence of driving after using cannabis, and of being a passenger with someone who is driving after using cannabis, in relation to place of residence (rural or non-rural) and in the weeks and months before and after legalization. Three time points were compared: pre-legalization, two months following legalization and 1 year after legalization.

RESULTS

At the national level, there are no significant differences between the predicted estimates of driving after using cannabis for those who live in rural and non-rural areas. However, when examining the impact of legalization, we found a significant increase in driving after using cannabis among rural residents directly following legalization. Furthermore, it was observed that this increase in driving after using cannabis returns to pre-legalization rates one year after legalization. By contrast, in the weeks and months following legalization, driving after using cannabis decreased among those living in non-rural areas, and slowly increased soon thereafter. No significant differences were observed, in either time period or group, in the prevalence of being a passenger with someone who is driving after using cannabis.

CONCLUSIONS

The finding of significantly higher risk of driving after use of cannabis soon after legalization in rural areas suggests a need for more attention to address immediate concerns for public safety. The increased potential for traffic injuries and deaths in other jurisdictions contemplating legalization supports the call for more and better targeted prevention efforts in rural communities that have far too often been overlooked and under-served.

A study into the nature and extent of polydrug use in driving recidivism behavior

OBJECTIVE

Polydrug use has become a frequent pattern of drug consumption in Europe, and this is considered a particularly dangerous risk factor for impaired driving. In Italy, persons whose license has been revoked or suspended due to the use of psychoactive drugs can reapply for a new driving license, depending on the judgment of the relevant local medical committee (CML). To regain a revoked license, offenders must remain drug free throughout an observation period. An important problem with enforcement of impaired driving is recidivism. The aim of the present study is to analyze the influence of polydrug use on driving recidivism.

METHOD

We report the findings of several years' experience at the forensic toxicology laboratory of the University of Macerata. Hair samples collected over a 7-year period by the CML from drug users were analyzed for cocaine, opiates, and cannabis using gas chromatography-mass spectrometry.

RESULTS

Three hundred thirty-five of the tested subjects were recidivists. Recidivism was more frequent among monodrug users (81%) compared with polydrug users (19%), but logistic regression showed that polydrug use is certainly a risk factor for recidivism compared to monodrug use (odds ratio [OR] = 1.99). The sex and age distribution of recidivist subjects showed a strong predominance of males in both groups, but there were no sex differences. There were more recidivist polydrug users than recidivist monodrug users in the younger age groups (OR = 2.012). Cocaine use was most prevalent in the recidivist monodrug group. All drugs analyzed were demonstrated to be a risk factor for recidivism among monodrug users, whereas only the cocaine and cannabis combination was shown to be a risk factor for recidivism among polydrug users (OR = 1.65 versus cocaine; OR = 1.30 versus Δ9-tetrahydrocannabinol). Almost all polydrug users became monodrug users, and cocaine was the most frequently detected drug in the subsequent test during the monitoring phase.

CONCLUSIONS

Our results show that polydrug use increases the risk of impaired driving recidivism and represents a considerable threat to road safety.

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.

Longitudinal Assessment of Postconcussion Driving: Evidence of Acute Driving Impairment

BACKGROUND

Current medical practices and recommendations largely ignore the safety of postconcussion driving, even though commonly used measures of neurocognition, balance, and vestibulo-ocular function show impairment.

PURPOSE

To compare simulated driving between patients with concussion and controls throughout concussion recovery using a case-control design.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 26 concussed and 23 control Division I collegiate athletes completed a driving simulation assessment at 3 time points (within 72 hours, asymptomatic, and return to sport). Cumulative driving simulation outcome variables included total number of collisions, speed exceedances, stop signs missed, lane excursions, total drive time, percentage of time over the speed limit, and percentage of time out of the lane. The mean speed, standard deviation of speed (SDS), lateral lane position, and standard deviation of lateral lane position (SDLP) were examined for each of the 11 drive segments. Outcomes were compared using generalized linear mixed models with random intercepts by participant with Poisson or normal distributions.

RESULTS

Within 72 hours of injury, the concussion group committed more lane excursions (median difference, 2; P = .003), exhibited greater SDS while avoiding a child pedestrian crossing the road (Cohen d = 0.73; P = .011), drove ~7 inches (~18 cm) closer to the centerline during a residential left curve (d = 0.90; P = .015), and had greater SDLP while navigating around a car crash compared with controls (d = 0.72; P = .016). When asymptomatic, the concussion group committed fewer speed exceedances (median difference, 2; P = .002) and had lower SDLP while navigating through a traffic light compared with controls (d = 0.60; P = .045). No differences were evident at return to sport. Groups did not differ in total collisions at any time point.

CONCLUSION

The concussion group showed more impaired driving patterns within 72 hours of injury, drove more conservatively once asymptomatic, and had similar driving performance at the time they returned fully to sport. Clinicians should consider these findings when discussing driving with patients acutely after concussion. Further research is needed to determine whether on-road collision risk is elevated after concussion.

Drunk driving policies and breath test refusal in Taiwan

OBJECTIVE

Driving under the influence (DUI) is one of the major causes of traffic crashes in Taiwan, leading to huge medical expenditures and human capital loss. Although the authorities have enacted several policies to reduce drunk driving, most penalties are based on drunk drivers' alcohol levels. According to Taiwan regulations, drivers could pay a fine to refuse the breath test if they are not involved in a traffic collision, and there is no clear evidence showing that they are DUI. Therefore, increased sanctions for DUI may lead to increased breath test refusals. If breath tests for drunk driving could be refused with little or no punishments for drivers, then the detection of behavioral impairment would weaken, and the deterrent effect of DUI punishment would be limited.

METHOD

This research uses interrupted time-series analysis (ITSA) to examine how policy reforms from 2007 to 2020 affected driver's breath refusal rate in Taiwan.

RESULTS

We find that said reforms that exclusively increase the punishment of DUI offenders did raise the refusal rate immediately and persistently, suggesting that more drunk drivers would refuse a breath test to avoid more severe DUI punishment. Policy reforms that increase penalties for drivers refusing to take breath tests may instantly lower the refusal rate, but the long-term effects are contingent upon the DUI punishment.

CONCLUSIONS

It appears that drunk drivers could still decide on breath test refusal to avoid a DUI conviction if the punishment for refusing the test is less severe than that for DUI. Aggravating penalties for refusing breath tests would decrease the refusal rate and help reinforce DUI's deterrent effect.

Collisions and cannabis: Measuring the effect of recreational marijuana legalization on traffic crashes in Washington State

OBJECTIVE

Washington State was among the first states in the US to legalize recreational consumption and retail sales of marijuana. Recreational use of cannabis was legalized December 6, 2012, following the passage of Initiative 502 30 days prior. Roughly 19 months later the first retail cannabis stores opened their doors for public sales ("commercialization"). I measure the impact of cannabis legalization and commercialization on traffic collisions in Washington State.

METHODS

With county-level vehicle crash data from the Washington State Department of Transportation collected monthly, I utilize an interrupted time-series framework with Poisson estimation to compare traffic collisions with recreational retail cannabis sales revenue from 2011 (three years pre-commercialization) through 2017 (three years post-commercialization). First, I measure the shift in collisions brought about by Washington's 2012 cannabis legalization. Then, I compare retail cannabis sales-a measure of commercialization-to traffic collisions based on severity of injury (fatal, severe injury, minor injury, non-injury, and all).

RESULTS

After controlling for confounding factors, evidence suggests that recreational cannabis legalization led to fewer fatal and serious injury collisions. Retail cannabis sales generally correlate with more traffic collisions, particularly for less severe (minor injury) crashes. These findings are robust to the inclusion of additional control variables pertaining to county-level cannabis usage and driving behavior while intoxicated.

CONCLUSIONS

Cannabis legalization led to fewer fatal, serious, and minor injury collisions. Commercialization (cannabis sales) correlated with an increase in less severe crashes. Although cannabis use generally increased in Washington State following legalization/commercialization, survey data suggest that driving behavior while under the influence of cannabis did not change significantly over the post-commercialization period. Future research should focus on measuring the dose-dependent impact of cannabis consumption on traffic collisions. This should include recognition of the importance of cannabis dosing, timing, and route of consumption. Lastly, the dangers of poly-drug driving-particularly cannabis and alcohol-are well established and should be high priority for further research.

Self-reported impacts of recreational and medicinal cannabis use on driving ability and amount of wait time before driving

OBJECTIVE

Past research indicates that driving after cannabis use is relatively common. However, not all cannabis users are equally likely to drive after use; frequent cannabis users and frequent drivers are most at risk. It has been suggested that this is due to a perceived lack of impact of cannabis on driving ability.

METHODS

The current study sought to better understand the motivation to drive after recent cannabis use. A survey was used to examine the self-reported impact of cannabis use on driving ability and, further, the amount of time cannabis users wait before driving after use. A total of 562 participants were recruited. Of these, 424 completed the survey and were included for analysis. Purposive sampling was used to screen for cannabis users who were over the age of 18 and residents of Connecticut.

RESULTS

Cannabis use frequency was found to predict the self-reported impact of both recreational and medicinal cannabis on driving ability, such that more frequent cannabis users reported less impairment. Additionally, cannabis use frequency was predictive of wait time before driving, where more frequent users reported waiting less time before driving after cannabis use. A plurality of participants reported not waiting at all before driving after using cannabis. Notably, the self-reported impact of cannabis on driving ability was not associated with wait time before driving.

CONCLUSIONS

Cannabis users may not wait before driving even if they think it has a negative impact on their driving ability. Other factors that potentially impact driving after using cannabis warrant investigation.

Cannabis legalization and traffic injuries: exploring the role of supply mechanisms

BACKGROUND AND AIM

In Uruguay, residents age 18 and older seeking legal cannabis must register with the government and choose one of three supply mechanisms: self-cultivation, non-profit cannabis clubs or pharmacies. This is the first paper to measure the association between type of legal cannabis supply mechanism and traffic crashes involving injuries.

DESIGN

Ecological study using ordinary least squares regression to examine how department-level variation in registrations (overall and by type) is associated with traffic crashes involving injuries.

SETTING

Uruguay.

CASES

532 department-quarters.

MEASUREMENTS

Quarterly cannabis registration counts at the department level and incident-level traffic crash data were obtained from government agencies. The analyses controlled for department-level economic and demographic characteristics and, as a robustness check, we included traffic violations involving alcohol for departments reporting this information. Department-level data on crashes, registrations and alcohol violations were denominated by the number of residents ages 18 and older.

FINDINGS

From 2013 to 2019, the average number of registrations at the department-quarter level per 10 000 residents age 18 and older for self-cultivation, club membership and pharmacy purchasing were 17.7 (SD = 16.8), 3.6 (SD = 8.6), and 25.1 (SD = 50.4), respectively. In our multivariate regression analyses, we did not find a statistically significant association between the total number of registrations and traffic crashes with injuries (β = -0.007; P = 0.398; 95% CI = -0.023, 0.01). Analyses focused on the specific supply mechanisms found a consistent, positive and statistically significant association between the number of individuals registered as self-cultivators and the number of traffic crashes with injuries (β = 0.194; P = 0.008; 95% CI = 0.058, 0.329). Associations for other supply mechanisms were inconsistent across the various model specifications.

CONCLUSIONS

In Uruguay, the number of people allowed to self-cultivate cannabis is positively associated with traffic crashes involving injuries. Individual-level analyses are needed to assess better the factors underlying this association.

The effects of cannabis and alcohol on driving performance and driver behaviour: a systematic review and meta-analysis

BACKGROUND AND AIMS

Cannabis and alcohol are frequently detected in fatal and injury motor vehicle crashes. While epidemiological meta-analyses of cannabis and alcohol have found associations with an increase in crash risk, convergent evidence from driving performance measures is insufficiently quantitatively characterized. Our objectives were to quantify the magnitude of the effect of cannabis and alcohol-alone and in combination-on driving performance and behaviour.

METHODS

Systematic review and meta-analysis. We systematically searched Academic Search Complete, CINAHL, Embase, Scopus, Google Scholar, MEDLINE, PsycINFO, SPORTDiscus and TRID. Of the 616 studies that underwent full-text review, this meta-analysis represents 57 studies and 1725 participants. We extracted data for hazard response time, lateral position variability, lane deviations or excursions, time out of lane, driving speed, driving speed variability, speed violations, time speeding, headway, headway variability and crashes from experimental driving studies (i.e. driving simulator, closed-course, on-road) involving cannabis and/or alcohol administration. We reported meta-analyses of effect sizes using Hedges' g and r.

RESULTS

Cannabis alone was associated with impaired lateral control [e.g. g = 0.331, 95% confidence interval (CI) = 0.212-0.451 for lateral position variability; g = 0.198, 95% CI = 0.001-0.395 for lane excursions) and decreased driving speed (g = -0.176, 95% CI = -0.298 to -0.053]. The combination of cannabis and alcohol was associated with greater driving performance decrements than either drug in isolation [e.g. g = 0.480, 95% CI = 0.096-0.865 for lateral position variability (combination versus alcohol); g = 0.525, 95% CI = 0.049-1.002 for time out of lane (versus alcohol); g = 0.336, 95% CI = 0.036-0.636 for lateral position variability (combination versus cannabis; g = 0.475, 95% CI = 0.002-0.949 for time out of lane (combination versus cannabis)]. Subgroup analyses indicated that the effects of cannabis on driving performance measures were similar to low blood alcohol concentrations. A scarcity of data and study heterogeneity limited the interpretation of some measures.

CONCLUSIONS

This meta-analysis indicates that cannabis, like alcohol, impairs driving, and the combination of the two drugs is more detrimental to driving performance than either in isolation.

Towards the Validation of an Observational Tool to Detect Impaired Drivers-An Online Video Study

Abuse of alcohol and other drugs is a major risk factor at work. To reduce this risk, workplace drug testing is performed in transportation and other industries. VERIFY, an observational method, is one of the key elements in a procedure adopted by the police of the canton of Zurich, Switzerland, for detecting impaired drivers. The observational method has been successfully applied by adequately trained police officers since 2014. The aim of this study is to examine the interrater reliability of the observational method, the effect of training in use of the method, and the role of having experience in the police force and traffic police force on the outcome when rating a driver’s impairment. For this purpose, driver impairment in staged road traffic controls presented in videos was rated by laypeople (n = 81), and police officers without (n = 146) and with training (n = 172) in the VERIFY procedure. In general, the results recorded for police officers with training revealed a moderate to very good interrater reliability of the observational method. Among the three groups, impaired drivers were best identified by officers with training (ranging between 82.6% and 89.5% correct identification). Trained officers reported a higher impairment severity of the impaired drivers than the other two groups, indicating that training increases sensitivity to signs of impairment. Our findings also suggest that online video technology could be helpful in identifying impaired drivers. Trained police officers could be connected to a road traffic control to make observations via live video. By this method efficiency and reliability in detecting abuse of alcohol and other drugs could be improved. Our findings also apply to workplace drug testing in general.

Evaluating Long-Term Outcomes of a High School-Based Impaired and Distracted Driving Prevention Program

Motor vehicle crashes are one of the leading causes of death among teenagers. Many of these deaths are due to preventable causes, including impaired and distracted driving. You Drink, You Drive, You Lose (YDYDYL) is a prevention program to educate high school students about the consequences of impaired and distracted driving. YDYDYL was conducted at a public high school in Southern Nevada in March 2020. A secondary data analysis was conducted to compare knowledge and attitudes of previous participants with first-time participants. Independent-samples-t test and χ2 test/Fisher’s exact test with post-contingency analysis were used to compare pre-event responses between students who had attended the program one year prior and students who had not. Significance was set at p < 0.05. A total of 349 students participated in the survey and were included for analysis; 177 had attended the program previously (50.7%) and 172 had not (49.3%). The mean age of previous participants and first-time participants was 16.2 (SD ± 1.06 years) and 14.9 (SD ± 0.92 years), respectively. Statistically significant differences in several self-reported baseline behaviors and attitudinal responses were found between the two groups; for example, 47.4% of previous participants compared to 29.4% of first-time participants disagreed that reading text messages only at a stop light was acceptable. Students were also asked how likely they were to intervene if a friend or family member was practicing unsafe driving behaviors; responses were similar between the two groups. The baseline behaviors and attitudes of participants regarding impaired and distracted driving were more protective among previous participants compared to first-time participants, suggesting the program results in long-term positive changes in behaviors and attitudes. The results of this secondary retrospective study may be useful for informing the implementation of future impaired and distracted driving prevention programs.

Estimating Cannabis Involvement in Fatal Crashes in Washington State Before and After the Legalization of Recreational Cannabis Consumption Using Multiple Imputation of Missing Values

The government of Washington state legalized recreational cannabis consumption in December 2012. We used data on all drivers involved in fatal crashes in Washington in the years 2008-2019 (n = 8,282) to estimate prevalence in fatal crashes of drivers with ∆9-tetrahydrocannabinol (THC; the main psychoactive compound in cannabis) in their blood before and after legalization. However, nearly half of the drivers were not tested for drugs; we therefore used multiple imputation to estimate THC presence and concentration among them. We used logistic regression followed by marginal standardization to estimate the adjusted prevalence of THC-positive drivers after legalization relative to what would have been predicted without legalization. In the combined observed and imputed data, the proportion of drivers positive for THC was 9.3% before and 19.1% after legalization (adjusted prevalence ratio: 2.3, 95% confidence interval: 1.3, 4.1). The proportion of drivers with high THC concentrations increased substantially (adjusted prevalence ratio: 4.7, 95% confidence interval: 1.5, 15.1). Some of the increased prevalence of THC-positive drivers might have reflected cannabis use unassociated with driving; however, the increased prevalence of drivers with high THC concentrations suggests an increase in the prevalence of driving shortly after using cannabis. Other jurisdictions should compile quantitative data on drug test results of drivers to enable surveillance and evaluation.

State alcohol ignition interlock laws and fatal crashes

OBJECTIVE

Alcohol-impaired driving results in thousands of deaths annually. Alcohol ignition interlocks require a negative breath test to start a vehicle's engine, and 44 states have mandated some form of interlock law for drivers convicted of driving while intoxicated (DWI). The objective of this study was to estimate the association between interlock laws and fatal impaired-driving crashes.

METHODS

Differences in three interlock laws were evaluated by comparing alcohol-impaired passenger vehicle drivers involved in fatal crashes between 2001 and 2019 in the United States across state and time. State/time differences unrelated to interlock laws were controlled for by fitting a Poisson model. The exposure measure was the number of passenger vehicle drivers in fatal crashes that did not involve impaired drivers. Laws requiring interlocks for drivers convicted of DWI covered: repeat offenders, repeat offenders and high-BAC offenders, all offenders, or none.

RESULTS

The number of states with all-offender interlock laws during the study period went from three in 2001 to 29 in 2019, and the number of states with any of the three laws increased from 16 to 44. All-offender laws were associated with 26% fewer drivers with 0.08+ BAC involved in fatal crashes, compared with no law. Repeat-offender laws were associated with a 9% reduction in impaired drivers, compared with no law. Repeat and high-BAC laws were associated with a 20% reduction in impaired drivers in fatal crashes, compared with no law.

CONCLUSION

Laws mandating alcohol ignition interlocks, especially those covering all offenders, are an effective impaired-driving countermeasure that reduces the number of impaired drivers in fatal crashes.

A Natural Experiment to Test the Effect of Sanction Certainty and Celerity on Substance-Impaired Driving: North Dakota's 24/7 Sobriety Program

OBJECTIVES

Evaluate the deterrent effect of a program that increases the certainty and celerity of sanction for arrestees ordered to abstain from alcohol and other drugs on substance-impaired driving arrests.

METHODS

We examine participant compliance with orders to abstain from alcohol and other drug use via breathalyzer, body-worn continuous alcohol monitoring (CAM) devices, transdermal drug patches, and urinalyses. We then evaluate the impact of the 24/7 Sobriety program on substance-impaired driving arrests. Using variation across counties in the timing of program implementation in North Dakota as a natural experiment, we use differences-in-differences fixed effects Poisson regressions to measure the program's effect on county-level arrests for substance-impaired driving.

RESULTS

Over half of participants ordered to abstain from substance use complete 24/7 Sobriety without a detected substance use event. At the county level, the program is associated with a 9 percent reduction in substance-impaired driving arrests after accounting for the impact of oil exploration in the Bakken region, law enforcement intensity, alcohol availability, whether the state's large universities were in session, and socio-demographic characteristics.

CONCLUSIONS

The results suggest frequent monitoring combined with increased sanction celerity deters substance use-involved crime. While the results are generally consistent with an earlier study of 24/7 Sobriety in another state, differences in the study outcome measures and implementation choices across states make direct comparisons difficult. More can be learned by conducting randomized controlled trials that vary time on program, testing technology, and/or level of sanction.

Cannabis Use and Car Crashes: A Review

In this review, state-of-the-art evidence on the relationship between cannabis use, traffic crash risks, and driving safety were analyzed. Systematic reviews, meta-analyses, and other relevant papers published within the last decade were systematically searched and synthesized. Findings show that meta-analyses and culpability studies consistently indicate a slightly but significantly increased risk of crashes after acute cannabis use. These risks vary across included study type, crash severity, and method of substance application and measurement. Some studies show a significant correlation between high THC blood concentrations and car crash risk. Most studies do not support this relationship at lower THC concentrations. However, no scientifically supported clear cut-off concentration can be derived from these results. Further research is needed to determine dose-response effects on driving skills combined with measures of neuropsychological functioning related to driving skills and crash risk.

Effects of Smoking Cannabis on Visual Function and Driving Performance. A Driving-Simulator Based Study

Cannabis is the most widely used illegal drug in the world. Limited information about the effects of cannabis on visual function is available, and more detail about the possible impact of visual effects on car driving is required. This study investigated the effects of smoking cannabis on vision and driving performance, and whether these effects are correlated. Twenty drivers and occasional users were included (mean (SE) age, 23.3 (1.0) years; five women). Vision and simulated driving performance were evaluated in a baseline session and after smoking cannabis. Under the influence of cannabis, certain visual functions such as visual acuity (p < 0.001), contrast sensitivity (p = 0.004) and stereoacuity (far, p < 0.001; near, p = 0.013) worsened. In addition, there was an overall deterioration of driving performance, with the task of keeping the vehicle in the lane proving more difficult (p < 0.05). A correlation analysis showed significant associations between driving performance and visual function. Thus, the strongest correlations were found between the distance driven onto the shoulder and stereoacuity, for near (ρ = 0.504; p = 0.001) and far distances (ρ = 0.408; p = 0.011). This study provides the first evidence to show that the visual effects of cannabis could impact driving performance, compromising driving safety. The results indicate that information and awareness campaigns are essential for reducing the incidence of driving under the influence of cannabis.

Potential lives saved by in-vehicle alcohol detection systems

OBJECTIVES

The objective of this study was to estimate the number of crash deaths specifically attributable to alcohol-impaired driving, with a focus on various strategies for introducing vehicle-based solutions. If alcohol detection systems are standard in all new vehicles, how many lives could be saved in the near term, and how long will it take to essentially eliminate alcohol-impaired driving? Alternatively, if such systems are offered as an option, how many lives could be saved?

METHODS

Fatal crashes in the United States during 2015-2018 were classified by the highest driver blood alcohol concentration (BAC) and the corresponding age category of that driver. Based on the estimates of relative risk (RR) for a given driver group, eliminating alcohol in the driver's blood should lower risk by the attributable proportion, 1 - 1/RR. Multiplying this quantity by the number of deaths for the driver group yielded the estimated number of lives potentially saved if the BACs were reduced to zero.

RESULTS

Systems that restrict drivers with any BAC could prevent nearly 12,000 deaths per year, while systems that restrict BAC to less than 0.08 g/dL could prevent more than 9,000 deaths. Within 3 years of a mandate for vehicle-based alcohol detection systems, it is expected that the annual lives saved would be between 1,000 and 1,300. Within 6 years, it would be between 2,000 and 2,600 lives saved per year, and within 12 years it would be between 4,600 and 5,900 lives saved per year. A system required only for those convicted of alcohol-impaired driving could save between 800 and 1,000 lives per year. A system available only to fleets of vehicles could save between 300 and 500 lives per year.

CONCLUSIONS

Vehicle-based interventions will not immediately solve the problem of alcohol-impaired driving, but they are an important component of the overall strategy. Even if required as standard equipment in all new vehicles, it will take 12 years before there are enough to reach more than half of their potential. If vehicle-based interventions are instead voluntary or introduced as options, then progress toward a solution will be much slower.

The impact of interlock installation on driving behavior and drinking behavior related to driving

OBJECTIVE

There is a substantial body of evidence that the recidivism of impaired-driving offenders is reduced while an ignition interlock device (IID) is on their vehicles. This study examines changes in driving behaviors and drinking behaviors used by DWI offenders to manage driving with the IID.

METHODS

A total of 166 IID participants who completed two surveys covering the period from arrest to IID installation (T1) and during IID use (T2) were examined. Four domains were covered: demographics, driving environments and transportation needs, reported driving activity, and reported drinking activities. Participants were on average 38 years old, 43% were female, 35% completed college, 34% had an income of more than $50,000, and 83% were employed. For those who provided it, the mean blood alcohol content (BAC) at arrest was .184 g/dL, with only 8 (5%) individuals below .08 g/dL, and 93 (56%) at over .18 g/dL. About 45% were repeat DWI offenders.

RESULTS

Between T1 and T2 there was a slight increase in acknowledging public transportation was available (p=.001), an increase in other individuals driving the interlock-equipped vehicle (p=.002), an increase in the number of vehicles in the household not registered to the DWI offender (p< .001), and an increase in the number of participants who reported that driving was important to their lifestyle (p=.008). Initial (T1) expectations about whether the interlock would be a problem were significantly different from actual experiences reported in T2 (p<.001). With respect to alcohol consumption, 14% reported abstinence at T2 compared to 2% at T1 (p=.001) and the number of drinks per drinking occasion decreased from a mean of 4.90 at T1 to 3.14 at T2 (p=.001), but the number of drinking occasions increased by a third (p=.003). The number of drinking locations (p=.001), the frequency of stopping after work for a drink (p=.001), and drinking at a bar all decreased (p<.001).

CONCLUSIONS

Interlock users make some adjustments in how they drink, the amount they drink, and where they drink. This finding suggests that there may be methods that can be used to extend the benefits of the IID beyond the sanction period.

Assessing Psychological Fitness to Drive for Intoxicated Drivers: Relationships of Cognitive Abilities, Fluid Intelligence, and Personality Traits

Our study explores the relationships between traffic-psychological driving-related personality traits, fluid intelligence, and cognitive abilities for drivers whose driver license has been revoked due to intoxicated driving (alcohol and/or drugs). We were able to show that high significant impacts on cognitive functions derive from the participants' age and fluid intelligence. In addition, driving-related personality traits like emotional instability, sense of responsibility and self-control contributed significantly to some of the cognitive abilities that are important for the fitness to drive. Additionally, mediating effects of fluid intelligence in the model are discussed. Traffic psychologists can use this knowledge in their assessment of drivers, mainly regarding the possible compensation of cognitive deficits regarding the fitness to drive.

Vehicle safety features aimed at preventing alcohol-related crashes

This review focuses on the role of motor vehicles in the prevention of alcohol-related fatalities in the United States. Since alcohol significantly affects brain function, it is natural to make drivers the prime targets for impaired-driving-prevention programs. However, the prevalence, design, ease of operation, and safety features of motor vehicles, as well as state regulations of their operation, have an important influence on crash occurrences, particularly those involving alcohol. This review begins with a discussion of why the automobile became the central technological device in the alcohol-related fatality problem and then moves on to an overview of motor vehicle safety programs that have impacted impaired driving. The article then presents an extended discussion of the effectiveness of vehicle-based, alcohol-detecting ignition interlock devices (interlocks), which provided the principal specific vehicle-based effort in the 20th century to separate alcohol consumption from driving. The review ends with a commentary on the issues that will arise in managing operator impairment in autonomous (self-driving) vehicles-the probable principal 21st-century effort to reduce impaired driving and eliminate alcohol-related crashes by minimizing the role of the driver.

Complexities of Young Driver Injury and Fatal Motor Vehicle Crashes

We offer a perspective on the literature discussing the importance of driving for youth, the complexities of learning to drive, and the risks of driving which lead to motor vehicle crashes (MVCs). Specifically, we discuss important underlying reasons why some adolescents and young adults may be more susceptible to engaging in driving behaviors which result in fatal MVCs; the leading cause of death among 15 to 20 y/o. Some of the factors known to lead to crash fatalities span the domains of cognitive development, distraction, alcohol/drug use, psychosocial development and peer influence, and young driver inexperience. While advancements in driver training, traffic safety legislation, vehicle safety engineering, and emergency/trauma care have helped reduce the prevalence of crashes, we suggest that natural brain maturation which occurs during adolescence and young adulthood may hold unique susceptibilities for young driver crashes. As such, we discuss the importance in using a multidisciplinary research approach, and specifically neuroscience methods, to develop a more compressive understanding of crash risk factors among young drivers. By using a multidisciplinary approach when studying young drivers, we can advance the injury and prevention science as well as inform relevant policies, innovative technologies, comprehensive training and intervention programs which will develop safer young drivers sooner.

Post-concussion driving management among athletic trainers

Primary objective: To describe and compare athletic trainer (AT) post-concussion driving management practices and opinions.Research design: Cross-sectional.Methods & procedures: A survey was sent via email to 8,723 ATs (10.8% response rate[945/8723]) to capture demographics, management practices, and opinions (agreement on a seven-point Likert scale). We used Kruskal-Wallis tests to compare the percentage of patients instructed to refrain from driving across the highest earned a degree, setting, and years certified (alpha = 0.05).Main outcomes & results: When asked whether they recommended patients with concussion refrain from driving, 58.5%(n = 553/945) of ATs responded "sometimes", 37.9%(n = 358/945) responded "always", and 3.6%(n = 34/945) responded "never". ATs responding "sometimes" or "always" estimated that they instruct 57.6 ± 37.6% of patients with concussion to refrain from driving. ATs most commonly: recommended that patients refrain from driving until symptom resolution(44.7%,n = 399/892); utilized their clinical exam (patient interview/history) to determine when a patient could resume driving(64.9%,n = 579/892); and provided instructions verbally(94.2%,n = 840/892). High school(60.5 ± 37.6%) and clinical ATs(66.5 ± 31.2%) trended toward higher percentages of patients they instruct to refrain from driving relative to college(52.3 ± 38.2%; χ²(2) = 5.92,p = .052).Conclusions: ATs recommend driving restrictions to some, but not all, patients with concussion. Overall, ATs recognize post-concussion driving dangers, but do not strongly endorse refraining from driving after a concussion. High school and clinical ATs may manage more adolescent novice drivers and, therefore, act more conservatively.

Associations between driving under the influence or riding with an impaired driver and future substance use among adolescents

Objective: Risky driving behaviors among adolescents, such as riding with a drinking or impaired driver (RWID) or driving while under the influence (DUI) of alcohol or drugs, are significant public health concerns. Few studies have examined associations of RWID and DUI with future substance use and problems after controlling for baseline substance use. Given that the DUI/RWDD event may be a teachable moment to prevent future consequences (e.g., when injured or arrested), it is important to understand how this risk behavior relates to subsequent use and problems. This study therefore examined characteristics of adolescents who reported DUI and RWID and assessed their risk of future alcohol and marijuana use and consequences 6 months later. Methods: Participants were 668 adolescents aged 12 to 18 (inclusive) recruited at 1 of 4 primary care clinics in Pittsburgh and Los Angeles as part of a larger randomized controlled trial. They completed surveys about their health behaviors at baseline and 6 months after baseline. We examined baseline characteristics of adolescents who reported DUI and RWID and then assessed whether past-year DUI and RWID at baseline were associated with alcohol and marijuana use and consequences 6 months after baseline. Results: Fifty-eight percent of participants were female, 56% were Hispanic, 23% were Black, 14% were White, 7% were multiethnic or other, and the average age was 16 years (SD = 1.9). At baseline, participants who reported RWID or DUI were more likely to be older, report past-year use of alcohol and marijuana, and more likely to have an alcohol use disorder or cannabis use disorder versus those who did not report RWID or DUI, respectively. At 6-month follow-up and after controlling for baseline demographics and baseline alcohol use, RWID was associated with more frequent drinking episodes in the past 3 months and greater number of drinks in the past month when they drank heavily. DUI at baseline was associated with more frequent heavy drinking episodes and alcohol and marijuana consequences 6 months later. Conclusions: RWID and DUI are significantly associated with greater alcohol and marijuana use over time. This study highlights that teens may be at higher risk for problem substance use in the future even if they ride with someone who is impaired. Prevention and intervention efforts for adolescents need to address both driving under the influence and riding with an impaired driver to prevent downstream consequences.

Marijuana trajectories and associations with driving risk behaviors in Canadian youth

Objective: Research on risky driving practices involving marijuana use among youth and young adults often relies on cross-sectional data, which fail to account for longitudinal changes in substance use patterns. A better understanding of the longitudinal patterns of marijuana use and its effect on risky driving practices during young adulthood is needed in order to better inform prevention efforts. The current study examined whether different longitudinal patterns of marijuana use across the transition from adolescence to young adulthood are associated with impaired driving risks in young adulthood. Methods: Data were from the longitudinal Victoria Healthy Youth Survey, which interviewed youth biennially on 6 occasions across 10 years (2003 to 2013). Results: Youth who reported consistently high levels of marijuana use from adolescence to young adulthood (chronic users) and youth who reported increasing levels of use across this period (increasers) were more likely to engage in risky impaired driving behaviors compared to the other 3 user groups (occasional users, decreasers, and abstainers). Frequency of marijuana use was also predictive of impaired driving risks in young adulthood after controlling for individual characteristics (age, sex, socioeconomic status, age of onset of marijuana use), frequency of other substance use (heavy episodic drinking and illicit drug use), and simultaneous use of marijuana and other substances (alcohol and illicit drugs). By young adulthood, youth who use marijuana more than once a week are more likely to simultaneously use alcohol and engage in heavy episodic drinking. They are also more likely take driving risks. Conclusions: Harm reduction strategies and legislative approaches targeting impaired driving risks associated with marijuana use should include approaches to target these high-risk groups and to reduce simultaneous use of alcohol.

Exploring perceptions among people who drive after cannabis use: Collision risk, comparative optimism and normative influence

INTRODUCTION AND AIMS

While the perceived risks of driving under the influence of cannabis (DUIC) have been a focus of recent drug-driving research, relevant concepts from the social cognition literature have rarely been applied to inform understanding of DUIC. This study aims to expand knowledge of perceived collision risk and social influences associated with DUIC and driving after other substance use.

DESIGN AND METHODS

Semi-structured interviews were conducted with 20 participants of a remedial program for impaired drivers. Thematic analysis began with two independent coders. Early discussion of emergent themes resulted in the identification of applicable social cognition concepts, resulting in selective coding and interpretation.

RESULTS

Many participants identified DUIC as less risky than driving under the influence of alcohol or other drugs. Mixed perceptions regarding the dangerousness of DUIC were expressed, with some participants denying increased collision risk except among novice cannabis users. Comparative optimism bias was also expressed by participants who perceived themselves as less likely than others to be involved in a collision when DUIC. In view of normative influence, friends were generally seen as more accepting of DUIC than family, and there were indications that the opinions of others who use cannabis were regarded as more credible than the opinions of those who do not use the drug.

DISCUSSION AND CONCLUSIONS

Comparative optimism bias and normative influence may contribute to perceived risks associated with DUIC and may, therefore, be useful concepts to employ to increase the effectiveness of public health and road safety initiatives.

Exploring substance use and impaired driving among adults aged 21 years and older in the United States, 2015

INTRODUCTION

Alcohol- or drug-impaired driving can cause motor vehicle crashes, injuries, and death. Estimates of drug-impaired driving are difficult to obtain. This study explores self-reported prevalence of and factors associated with alcohol, marijuana, and prescription opioid use and impaired driving among adults aged 21 years and older in the United States.

METHODS

Self-reported data from 3,383 adults in the 2015 Fall ConsumerStyles survey were analyzed. Respondents were asked about alcohol, marijuana, and prescription opioid use and driving while impaired in the last 30 days. Weighted prevalence estimates were calculated. Prevalence ratios and Poisson log-linear regressions were used to identify factors associated with substance use and impaired driving.

RESULTS

Alcohol use was reported by 49.5% (n = 1,676) of respondents; of these, 4.9% (n = 82) reported alcohol-impaired driving. Marijuana use was reported by 5.5% (n = 187) of respondents; of these, 31.6% (n = 59) reported marijuana-impaired driving. Prescription opioid use was reported by 8.8% (n = 298) of respondents; of these, 3.4% (n = 10) reported prescription opioid-impaired driving. Polysubstance use of alcohol and marijuana (concurrent use) was reported by 2.7% (n = 93) of respondents. Among those, 10.8% (n = 10) reported driving impaired by both alcohol and marijuana.

CONCLUSIONS

Impaired driving was self-reported among alcohol, marijuana, and prescription opioid users. This article demonstrates the need for more robust alcohol- and drug-related data collection, reporting, and analyses, as well as the emerging need for surveillance of marijuana and prescription opioid-impaired driving. States can consider using proven strategies to prevent impaired driving and evaluate promising practices.

Evaluation of a responsible beverage service and enforcement program: Effects on bar patron intoxication and potential impaired driving by young adults

OBJECTIVE

Studies of alcohol-related harm (violence, injury, illness) suggest that the most significant risk factors are the amount of alcohol consumed and whether obviously intoxicated patrons continue to be served. This study's objective was to investigate the effects of a responsible beverage service (RBS)/enhanced alcohol enforcement intervention on bars, bar patrons, and impaired driving.

METHOD

Two communities-Monroe County, New York, and Cleveland, Ohio-participated in a demonstration program and evaluation. The intervention applied RBS training, targeted enforcement, and corrective actions by law enforcement to a random sample of 10 identified problem bars in each community compared to 10 matched nonintervention problem bars. Data were collected over 3 waves on bar serving practices, bar patron intoxication, drinking and driving, and other alcohol-related harm from intervention and control bars and treatment and comparison communities.

RESULTS

In Monroe County, New York, of the 14 outcome measures analyzed, 7 measures showed statistically significant differences from pre- to postintervention. Six of those measures indicated changes in the desired or positive direction and 2 measures were in the undesired or negative direction. Of note in the positive direction, the percentage of intervention bar patrons who were intoxicated decreased from 44 to 27% and the average blood alcohol concentration of patrons decreased from 0.097 to 0.059 g/dL pre- to postintervention. In Cleveland, Ohio, 6 of the 14 measures showed statistically significant changes pre- to postintervention with 6 in the positive direction and 4 in the negative direction. Of note, the percentage of pseudo-intoxicated patrons denied service in intervention bars increased from 6 to 29%.

CONCLUSIONS

Of the 14 outcome measures that were analyzed in each community, most indicated positive changes associated with the intervention, but others showed negative associations. About half of the measures showed no significance, the sample sizes were too small, or the data were unavailable. Therefore, at best, the results of these demonstration programs were mixed. There were, however, some positive indications from the intervention. It appears that when bar managers and owners are aware of the program and its enforcement and when servers are properly trained in RBS, fewer patrons may become intoxicated and greater efforts may be made to deny service to obviously intoxicated patrons. Given that about half of arrested impaired drivers had their last drink at a licensed establishment, widespread implementation of this strategy has the potential to help reduce impaired driving.

Sobriety checkpoint and open container laws in the United States: Associations with reported drinking-driving

OBJECTIVE

The objective of this study was to assess how 2 types of drinking-driving laws-permitting sobriety checkpoints and prohibiting open containers of alcohol in motor vehicles-are associated with drinking-driving and how enforcement efforts may affect these associations.

METHODS

We obtained 2010 data on state-level drinking-driving laws and individual-level self-reported drinking-driving from archival sources (Alcohol Policy Information System, NHTSA, and Behavioral Risk Factor Surveillance System). We measured enforcement of the laws via a 2009 survey of state patrol agencies. We computed multilevel regression models (separate models for each type of law) that first examined how having the state law predicted drinking-driving, controlling for various state- and individual-level covariates; we then added the corresponding enforcement measure as another potential predictor.

RESULTS

We found that states with a sobriety checkpoint law, compared with those without a law, had 18.2% lower drinking-driving; states that conducted sobriety checks at least monthly (vs. not conducting checks) had 40.6% lower drinking-driving (the state law variable was not significant when enforcement was added). We found no significant association between having an open container law and drinking-driving, but states that conducted open container enforcement, regardless of having a law, had 17.6% less drinking-driving.

CONCLUSION

Our results suggest that having a sobriety checkpoint law and conducting checkpoints as well as enforcement of open containers laws may be effective strategies for addressing drinking-driving.

Driving under the influence of alcohol in professional drivers in Cameroon

BACKGROUND

Professional drivers play a pivotal role in transporting people and goods in Cameroon. Alcohol misuse is frequent in Cameroon, but its impact on professional drivers has never been studied. This study assessed driving under the influence of alcohol and its correlates in professional drivers in Cameroon.

METHODS

A cross-sectional study was conducted at 4 sites on the Yaoundé-Douala highway during a 10-day period in 2014. At each site, professional drivers were randomly stopped during a 24-h window and their breath was sampled for alcohol use. The prevalence of driving under the influence (the equivalent of blood alcohol level ≥ 1 mg/100 mL) and impaired driving (blood alcohol level ≥ 40 mg/100 mL) was computed for all drivers. The correlates of driving under the influence were assessed using logistic regression analysis.

RESULTS

Of the 807 professional drivers stopped, complete data for 783 were available. Almost all were men (n = 781). The mean age of drivers was 38.3 years (SD = 8.9). About one in 10 drivers (n = 77, 9.8%) tested positive for driving under the influence. About 2.8% (n = 22) had blood alcohol levels ≥ 40 mg/100 mL (legal limit in the United States) and 1.4% (n = 11) had blood alcohol levels ≥ 80 mg/100 mL. The likelihood of driving under the influence increased in drivers scoring 8 or more on Alcohol Use Disorder Identification Test (adjusted odds ratio [aOR] = 3.60; 95% confidence interval [CI], 2.14-6.07) and in those having a nighttime driving schedule (aOR = 4.43; 95% CI, 1.33-14.77).

CONCLUSION

These findings suggest that increasing enforcement to counter impaired driving in professional drivers in Cameroon is needed. Interventions might include screening for alcohol misuse and hazardous occupational practices.

Driving under the influence of non-alcohol drugs--An update. Part II: Experimental studies

Experimental studies on the impairing effects of drugs of relevance to driving-related performance published between 1998 and 2015 were reviewed. Studies with on-the-road driving, driving simulators, and performance tests were included for benzodiazepines and related drugs, cannabis, opioids, stimulants, GHB, ketamine, antihistamines, and antidepressants. The findings in these experimental studies were briefly discussed in relation to a review of epidemiological studies published recently. The studies mainly concluded that there may be a significant psychomotor impairment after using benzodiazepines or related drugs, cannabis, opioids, GHB, or ketamine. Low doses of central stimulants did not seem to cause impairment of driving behavior.

Methods for Quantifying the Clinical Significance of Change During Intervention Program Participation

Assessing the practical or clinical significance (CS) of an intervention program's outcomes is useful in determining its effectiveness. The CS approach gives information beyond traditional analyses by quantifying the proportions of people who meaningfully improve and deteriorate. We link latent transition analyses (LTA) to the CS literature and use a case study to contrast it with the long-standing Jacobson and Truax (JT) approach. Data came from 2,717 individuals convicted of a substance-related offense who participated in an indicated prevention program Prime For Life^® (PFL). We selected outcomes describing drinking beliefs and behavior. Both CS approaches categorized a majority of participants as improved (i.e., transitioning from baseline subgroups with risky behaviors and cognitions into posttest subgroups showing lower risk). Results demonstrate how the JT approach allows the assessment of improvements on individual outcomes, while the LTA provides more nuanced information about risk groupings. Selecting a CS approach depends on research goals, availability of normative data, and data considerations. JT is an appropriate method when evaluating single outcomes. In contrast, LTA is better when a multivariate description is desired, advanced missing data handling methods are needed, or outcomes are not normally distributed. Although infrequently done, evaluating CS provides useful information about program effectiveness.

A Prospective Study of Psychiatric Comorbidity and Recidivism Among Repeat DUI Offenders

Psychiatric comorbidity has emerged as a key element distinguishing DUI offenders from others, and, in some cases, distinguishing repeat offenders from first-time offenders. This paper utilizes a prospective design to determine whether the comorbid disorders identified among repeat DUI offenders can predict recidivism. Seven hundred forty-three repeat DUI offenders were recruited from a two-week inpatient treatment program at which they received a standardized mental health assessment and followed across five years post-treatment to track DUI offense, motor vehicle-related offenses, and general criminal offenses. Psychiatric comorbidity, though it did not predict DUI recidivism specifically, predicted criminal re-offense more generally. In addition, there was a specific relationship between lifetime attention deficit disorder and repeated motor vehicle-related offenses. These findings suggest that for many repeat offenders, DUI is one outlet in a constellation of criminal behavior, and that psychiatric comorbidity increases vulnerability for criminal re-offense.

Lower Cortisol Activity is Associated with First-Time Driving while Impaired

Driving while impaired (DWI) is a grave and persistent high-risk behavior. Previous work demonstrated that DWI recidivists had attenuated cortisol reactivity compared to non-DWI drivers. This suggests that cortisol is a neurobiological marker of high-risk driving. The present study tested the hypothesis that this initial finding would extend to first-time DWI (fDWI) offenders compared to non-DWI drivers. Male fDWI offenders (n = 139) and non-DWI drivers (n = 31) were exposed to a stress task, and their salivary cortisol activity (total output and reactivity) was measured. Participants also completed questionnaires on sensation seeking, impulsivity, substance use, and engagement in risky and criminal behaviors. As hypothesized, fDWI offenders, compared to non-DWI drivers, had lower cortisol reactivity; fDWI offenders also showed lower total output. In addition, cortisol activity was the most important predictor of group membership, after accounting for alcohol misuse patterns and consequences and other personality and problem behavior characteristics. The findings indicate that attenuated cortisol activity is an independent factor associated with DWI offending risk at an earlier stage in the DWI trajectory than previously detected.

The Impact of the Proposed Changes for the DSM-5 on Diagnoses of First-time DUI/DWI Offenders

Driving while impaired (DWI) is a frequently committed crime with enormous individual and social costs. The type of disposition and/or treatment appropriate for an individual offender is often determined, in part, by diagnostic criteria based on the American Psychiatric Association's Diagnostic and Statistics Manual. The DSM-5 significantly modified these criteria by eliminating legal problems as a criterion and dropping the categories of abuse and dependence. A brief substance abuse focused interview was conducted with 658 consecutive first-time DUI offenders who were arrested for driving under the influence of alcohol. Most were white, well-educated males. Contingency analyses were utilized to compare the current with the new diagnostic criteria based on algorithms for both diagnostic formulations. The major change observed when moving from DSM-IV-TR to DSM-5 criteria was that, approximately 54% of first-time DUI/DWI offenders would no longer meet diagnostic criteria based on the DSM-5. Of the nearly 17% who met dependence criteria, the majority were in the severe designation of the DSM-5.

Enforcement of alcohol-impaired driving laws in the United States: a national survey of state and local agencies

OBJECTIVES

Enforcement of alcohol-impaired driving laws is an important component of efforts to prevent alcohol-involved motor vehicle fatalities. Little is known about the use of drinking-driving enforcement strategies by state and local law enforcement agencies or whether the use of strategies differs by agency and jurisdiction characteristics.

METHODS

We conducted two national surveys, with state patrol agencies (n = 48) and with a sample of local law enforcement agencies (n = 1,082) selected according to state and jurisdiction population size. We examined 3 primary enforcement strategies (sobriety checkpoints, saturation patrols, and enforcement of open container laws) and tested whether use of these strategies differed by jurisdiction and agency characteristics across state and local law enforcement agencies

RESULTS

Most state patrol agencies reported conducting sobriety checkpoints (72.9%) and saturation patrols (95.8%), whereas less than half (43.8%) reported enforcing open container laws. In contrast, a lower proportion of local law enforcement agencies reported using these alcohol-impaired driving enforcement strategies (41.5, 62.7, and 41.1%, respectively). Sobriety checkpoint enforcement was more common in states in the dry South region (vs. wet and moderate regions). Among local law enforcement agencies, agencies with a full-time alcohol enforcement officer and agencies located in areas where drinking-driving was perceived to be very common (vs. not/somewhat common) were more likely to conduct multiple types of impaired driving enforcement.

CONCLUSIONS

Recommended enforcement strategies to detect and prevent alcohol-impaired driving are employed in some jurisdictions and underutilized in others. Future research should explore the relationship of enforcement with drinking and driving behavior and alcohol-involved motor vehicle fatalities.

Reciprocal Associations Between Parental Monitoring Knowledge and Impaired Driving in Adolescent Novice Drivers

OBJECTIVE

Adolescent driving while alcohol/drug impaired (DWI) and parental monitoring knowledge may have notable interplay. However, the magnitude and direction of causality are unclear. This study examined possible reciprocal associations among adolescents between DWI and parental monitoring knowledge.

METHODS

The data were from waves 1, 2, and 3 (W1, W2, and W3) of the NEXT Generation Health Study, with longitudinal assessment of a nationally representative sample of 10th graders starting in 2009-2010 (n = 2,525 at W1) and analyzed in 2014. Those who had obtained an independent/unsupervised driving license were included for the analysis. Autoregressive cross-lagged path analysis was used to examine potential reciprocal associations between DWI and parental monitoring knowledge of both mothers and fathers, controlling for potential confounders.

RESULTS

Stability of fathers' and mothers' monitoring knowledge across 3 consecutive interview waves was identified. W1 monitoring knowledge of both fathers and mothers was prospectively associated with DWI at W2 but not for W2 with W3. A significant negative association between adolescent DWI at W2 and mothers' monitoring knowledge at W3 was found but not between W1 and W2. None of the associations between DWI and fathers' monitoring knowledge from W1 to W2 or from W2 to W3 were significant.

CONCLUSIONS

Early (10th grade) parental monitoring knowledge may predict lower adolescent self-reported DWI in 11th grade. More notably, adolescent DWI did not seem to increase parental monitoring knowledge. Future interventions are needed to improve parental monitoring knowledge and enhance awareness of the DWI risk in their adolescent novice drivers.

Association between riding with an impaired driver and driving while impaired

OBJECTIVE

To examine the association between driving while alcohol/drug impaired (DWI) and the timing and amount of exposure to others' alcohol/drug-impaired driving (riding while impaired [RWI]) and driving licensure timing among teenage drivers.

METHODS

The data were from waves 1, 2, and 3 (W1, W2, and W3, respectively) of the NEXT Generation Study, with longitudinal assessment of a nationally representative sample of 10th graders starting in 2009-2010. Multivariate logistic regression was used for the analyses.

RESULTS

Teenagers exposed to RWI at W1 (adjusted odds ratio [AOR] = 21.12, P < .001), W2 (AOR = 19.97, P < .001), and W3 (AOR = 30.52, P < .001) were substantially more likely to DWI compared with those reporting never RWI. Those who reported RWI at 1 wave (AOR = 10.89, P < .001), 2 waves (AOR = 34.34, P < .001), and all 3 waves (AOR = 127.43, P < .001) were more likely to DWI compared with those who never RWI. Teenagers who reported driving licensure at W1 were more likely to DWI compared with those who were licensed at W3 (AOR = 1.83, P < .05).

CONCLUSIONS

The experience of riding in a vehicle with an impaired driver increased the likelihood of future DWI among teenagers after licensure. There was a strong, positive dose-response association between RWI and DWI. Early licensure was an independent risk factor for DWI. The findings suggest that RWI and early licensure could be important prevention targets.

Drinking drivers and drug use on weekend nights in the United States

BACKGROUND

Studies of drinking drivers in alcohol-related crashes have shown that high breath-alcohol concentrations (BrACs) are associated with illegal drug use. Until the 2007 National Roadside Survey (NRS), the prevalence of drugs among drinking drivers on U.S. roads was unknown. Using NRS data, we explore how many drivers with positive BrACs may also be using drugs and their significance to current drinking-driving enforcement procedures.

METHODS

Based on a stratified, random sample covering the 48 U.S. contiguous states, we conducted surveys on weekend nights from July-November 2007. Of the 8384 eligible motorists contacted, 85.4% provided a breath sample; 70.0%, an oral fluid sample; and 39.1%, a blood sample. We conducted regression analyses on 5912 participants with a breath test and an oral fluid or blood test. The dependent variables of interest were illegal drugs (cocaine, cannabinoids, street drugs, street amphetamines, and opiates) and medicinal drugs (prescription and over-the-counter).

RESULTS

10.5% of nondrinking drivers were using illegal drugs, and 26 to 33% of drivers with illegal BrACs (≥ 0.08 g/dL) were using illegal drugs. Medicinal drug use was more common among nondrinking drivers (4.0%) than among drivers with illegal BrACs (2.4%).

CONCLUSIONS

The significant relationship between an illegal BrAC and the prevalence of an illegal drug suggests as many as 350,000 illegal drug-using drivers are arrested each year for DWI by U.S. alcohol-impaired driving enforcement. These drug-using drivers need to be identified and appropriate sanctions/treatment programs implemented for them in efforts to extend per se laws to unapprehended drug users.

Strengthening impaired-driving enforcement in the United States

OBJECTIVE

Progress in reducing alcohol-impaired driving crash fatalities in the United States has stagnated over the last 15 years. This article reviews 2 current U.S. driving-while-intoxicated (DWI) laws and their enforcement with an aim toward generating opportunities to improve their enforcement approaches.

METHODS

Impaired-driving enforcement methods in Europe and Australia are compared with those in the United States, and the legal basis for current DWI criminal procedures is examined.

RESULTS

An examination of relevant U.S. Supreme Court decisions and current legal practices indicates that the requirements for use of breath test technology to determine blood alcohol concentrations of drivers on public roads are not entirely clear. Several potential methods for using field breath test technology to improve the detection of impaired drivers are suggested. These include (a) breath testing all drivers stopped for certain violations that have a high probability of involving an impaired driver, (b) breath testing all drivers at sobriety checkpoints, and (c) breath testing all drivers involved in fatal and serious injury crashes.

CONCLUSIONS

Breath test technology has enabled other countries around the world to adopt and implement enforcement strategies that serve as both general and specific deterrents to alcohol-impaired driving. Many of these enforcement strategies have been shown to be effective. If any one of these strategies can be adopted in the United States, further progress in reducing impaired driving is probable. It may be necessary to provide the U.S. Supreme Court with a test case of breath testing all drivers at a sobriety checkpoint, depending upon whether or not a police agency is willing to use that strategy.

Drinking and driving in the United States: comparing results from the 2007 and 1996 National Roadside Surveys

OBJECTIVES

The objectives of this study were to (a) use data from the 2007 National Roadside Survey (NRS) to determine the characteristics of weekend nighttime drivers with positive blood alcohol concentrations (BACs) on U.S. roads in 2007; (b) determine the relationship of the driving environment and trip characteristics associated with drinking drivers; and (c) compare the findings for the 2007 NRS with those for the 1996 NRS.

METHODS

Like the 1996 NRS, the 2007 NRS used a stratified random national roadside survey sample of the contiguous 48 states and collected nighttime data on Fridays and Saturdays between 10 p.m. and 3 a.m. Officers directed 8384 drivers into off-road parking areas where our research team asked them to participate in the survey.

RESULTS

Of those approached, 7159 (85.4%) provided a breath test. Results revealed that 12 percent of the nighttime drivers had positive BACs, and of those, 2 percent were higher than the 0.08 BAC illegal limit in the United States. Since the 1996 NRS, we found significant reductions in the percentage of BAC-positive drivers across different demographic groups. Age was among the most significant factors associated with a weekend driver having a positive BAC. The probability that a driver would be drinking peaked in the 21- to 25-year-old age group. Male drivers were more likely than female drivers to be drinking, and Asian and Hispanic drivers were less likely than white drivers to be drinking. Drinking drivers were more likely to be driving short distances (5 or fewer miles) late at night (between 1 and 3 a.m.) and to be coming from a bar or restaurant. Finally, 26 percent of the drivers who reported that they would drive less than 5 miles on the night of the survey had positive BACs, compared to only 16 percent who indicated that they would drive between 6 and 20 miles and 10 percent who planned to drive more than 20 miles.

CONCLUSIONS

The 2007 NRS provides another benchmark in the 4-decade record of drinking drivers on American roads and provides a basis for measuring progress in combating driving under the influence during the coming decade.

Depression, Readiness for Change, and Treatment Among Court-Mandated DUI Offenders

OBJECTIVE

The current study is part of a larger study that was designed to evaluate the impact of brief interventions on subsequent alcohol and drug use of individuals convicted of driving under the influence (DUI). This element considers the interaction of depression levels with treatment on subsequent substance use and problems related to substance use.

METHODS

Subjects were referred to the Research Institute on Addictions from various courts in the Western New York area for clinical evaluation and treatment referral, if further treatment was indicated. A total of 765 individuals were referred to the program, with 549 agreeing to participate. Participants were assessed at baseline using a number of different measures, with depression and readiness to change among them. A follow-up assessment took place 18-24 months following the baseline, with subsequent treatment experiences being one of the primary measures of interest for this study. A total of 443 participants were successfully interviewed at follow-up.

RESULTS

The high depression group had greater readiness to change and a greater likelihood of entering treatment than the low depression group (p's < .001). ANCOVAs showed depression by treatment interactions for drug problem severity, drug use, DUI risk, alcohol expectancies, abstinence self-efficacy, and psychiatric distress (all p's < .05). Furthermore, the treated high depression group made the largest positive gains across all outcomes (all p's < .01).

CONCLUSIONS

The readiness to change, treatment entry, and ANCOVA results, all support Wells-Parker and her colleagues' approach that depression may be a strong indicator of DUI offenders' readiness to change their substance use behavior.

The prevalence of cannabis-involved driving in California

BACKGROUND

Various national surveys suggest that cannabis use is rising nationally and many States have passed legislation that has potential to increase usage even further. This presents a problem for public roadways, as research suggests that cannabis impairs driving ability.

METHODS

Anonymous oral fluid samples and breath tests were obtained from more than 900 weekend nighttime drivers randomly sampled from six jurisdictions in California. Oral fluid samples were assayed for the presence of Schedule I drugs. Drivers also completed information on self-reported drug use and possession of a medical cannabis permit. Data from the 2007 National Roadside Survey (collected using comparable methods) were used as a comparison.

RESULTS

Using the 2010 data, a total of 14.4% of weekend nighttime drivers tested positive for illegal drugs, with 8.5% testing positive for delta-9-tetrahydrocannabinol (THC). THC-positive rates varied considerably among jurisdictions, from a low of 4.3% in Fresno to a high of 18.3% in Eureka. A comparison with the 2007 NRS data found an increase in THC-positive drivers in 2010, but no increase in illegal drugs other than cannabis. Drivers who reported having a medical cannabis permit were significantly more likely to test positive for THC.

CONCLUSIONS

Cannabis-involved driving has increased in California since 2007. Nearly 1-in-10 weekend, nighttime drivers tested positive for THC, and in some jurisdictions, the rate was nearly 1-in-5. The possible contribution of cannabis legislation, such as decriminalization and medical cannabis usage, is discussed.

Do deterrence and social-control theories predict driving after drinking 15 years after a DWI conviction?

OBJECTIVE

This study investigates the utility of deterrence and social-control theories for prospective prediction of driving-while-impaired (DWI) outcomes of first-time DWI offenders.

METHOD

The sample consisted of a subset of 544 convicted first-time DWI offenders (N=337 females) who were interviewed 5 and 15 years after referral to a Screening Program in Bernalillo County, New Mexico. Variables collected at the 5-year (initial) interview were used in structural equation models to predict past 3-months, self-reported DWI at the 15-year follow-up (follow-up) interview. These variables represented domains defined by deterrence and social-control theories of DWI behavior, with one model corresponding to deterrence theory and one to social-control theory.

RESULTS

Both models fit the data. DWI jail time was positively related to perceived enforcement, which was negatively but not significantly related to self-reported DWI. Neither jail time for DWI nor perceived likelihood of arrest was linearly related to self-reported DWI at follow-up. Interactions between jail time and prior DWI behavior indicated relatively weaker associations between initial and 15-year DWI for those reporting more jail time.

CONCLUSION

Our prospective study demonstrated that for this convicted DWI offender cohort, classic formulations of deterrence and social-control theories did not account for DWI. However, results suggest that punishment may decrease the likelihood of DWI recidivism.

Traffic environment and demographic factors affecting impaired driving and crashes

INTRODUCTION

Data availability has forced researchers to examine separately the role of alcohol among drivers who crashed and drivers who did not crash. Such a separation fails to account fully for the transition from impaired driving to an alcohol-related crash.

METHOD

In this study, we analyzed recent data to investigate how traffic-related environments, conditions, and drivers' demographics shape the likelihood of a driver being either involved in a crash (alcohol impaired or not) or not involved in a crash (alcohol impaired or not). Our data, from a recent case-control study, included a comprehensive sampling of the drivers in nonfatal crashes and a matched set of comparison drivers in two U.S. locations. Multinomial logistic regression was applied to investigate the likelihood that a driver would crash or would not crash, either with a blood alcohol concentration (BAC)=.00 or with a BAC≥.05.

CONCLUSIONS

To our knowledge, this study is the first to examine how different driver characteristics and environmental factors simultaneously contribute to alcohol use by crash-involved and non-crash-involved drivers. This effort calls attention to the need for research on the simultaneous roles played by all the factors that may contribute to motor vehicle crashes.

Alcohol- and drug-involved driving in the United States: methodology for the 2007 National Roadside Survey

This article describes the methodology used in the 2007 U.S. National Roadside Survey to estimate the prevalence of alcohol- and drug-impaired driving and alcohol- and drug-involved driving. This study involved randomly stopping drivers at 300 locations across the 48 continental U.S. states at sites selected through a stratified random sampling procedure. Data were collected during a 2-hr Friday daytime session at 60 locations and during 2-hr nighttime weekend periods at 240 locations. Both self-report and biological measures were taken. Biological measures included breath alcohol measurements from 9,413 respondents, oral fluid samples from 7,719 respondents, and blood samples from 3,276 respondents.

Preventing impaired driving opportunities and problems

Impaired driving remains a significant public health problem in the United States. Although impressive reductions in alcohol-related fatalities occurred between 1982 and 1997, during which all 50 States enacted the basic impaired-driving laws, progress has stagnated over the last decade. Substantial changes in the laws and policies or funding for the enforcement of the criminal offense of driving while intoxicated (DWI) are needed for further substantial progress in reducing alcohol-related crash injuries. However, research indicates that evidence-based laws in the 50 States and current best practices in DWI enforcement are not being fully adopted or used. It seems, however, that effective operations, such as the low-staff check points that are routinely applied in many communities, could be extended to many more police departments. In addition, several enforcement methods have been proposed but never fully tested.

Identity consolidation and health risk behaviors in college students

OBJECTIVES

To investigate the protective role of personal identity consolidation against health risk behaviors in college-attending emerging adults.

METHODS

A multisite sample of 1546 college students completed measures of personal identity consolidation and recent risk behavior engagement.

RESULTS

Multivariate Poisson regression indicated that personal identity consolidation was negatively related to binge drinking, illicit drug use, sexual risk behaviors, and risky driving. These findings were consistent across gender, ethnicity, and place of residence.

CONCLUSIONS

A consolidated sense of personal identity may protect college-attending emerging adults from health-compromising behaviors. Health professionals could incorporate an identity development component into college health programming.

Toward national estimates of alcohol use disorders among drivers: results from the National Roadside Survey Pilot Program

OBJECTIVE

To determine whether drivers contacted at the roadside can be screened for alcohol use disorders (AUDs). Secondarily, to produce preliminary estimates of AUDs among drivers and estimate the relationship between AUD status and BAC measured at the roadside.

METHODS

A two-phase survey program was undertaken. In phase 1, 206 motorists were interviewed at the roadside using a 15-item AUD Survey derived from a condensed version of the AUDADIS and the AUDIT-C. One hundred sixty-seven of these motorists were invited, for a $25 incentive, to call the research team within 48 h of the roadside assessment to repeat the questionnaire and complete a more detailed AUD assessment. Phase 2 involved a 6-state pilot test of the AUD Survey as an add-on to the 2005 National Roadside Survey Pilot Program. The setting for both phases of the survey program was US roadways on weekends between 10 p.m. and 3 a.m.

RESULTS

Ninety-seven percent of all eligible drivers completed the AUD questionnaire. The correlation between roadside and telephone interview results was 0.3 for alcohol abuse, 0.6 for alcohol dependence and heavy drinking, and 0.7 for binge drinking. Alcohol abuse and dependence diagnoses had 0.6 and 0.7 correlations with diagnoses derived from the full AUDADIS and the AUDIT-C had a 0.8 correlation with the full AUDIT. There was also a statistically significant and positive relationship between having a positive BAC at the roadside and meeting criteria for heavy drinking.

CONCLUSIONS

AUD status can be effectively measured at the roadside. The poor reliability for alcohol abuse is related to underreporting of drinking and driving during roadside assessments, compared to telephone follow-up. Other measures of hazardous alcohol use should be used in the roadside context to measure alcohol abuse.