The Relative Risk of Alcohol-Involved Crashes as a Function of Time of Day.

OBJECTIVE: Epidemiological research has repeatedly found that alcohol-impaired driving is associated with elevated risk of crash involvement in a dose-response fashion. Although experimental studies show that alcohol impairment of cognitive and psychomotor driving skills is exacerbated by sleep deprivation, there is less evidence that the combination of drowsiness and alcohol predicts actual motor vehicle crashes. METHOD: We explored this by reanalyzing data from the National Highway Traffic Safety Administration Drug and Alcohol Crash Risk Study, constructing separate risk curves for daytime and nighttime hours. RESULTS: Controlling for driver demographics and driving exposure, and excluding other impairing drugs, we observed significantly greater risk of crash during the night versus the day at blood alcohol concentrations (BACs) between approximately .04 and .12 g/dl. Based on fitted point estimates, at .08 g/dl, the risk of crash at night was three times the risk of crash during the day. CONCLUSIONS: The association between BACs and crash risk was markedly different during daytime versus nighttime hours. Increased daytime risk was not observed until BACs exceeded the .08 g/dl per se legal limit. Results are interpreted as emphasizing the sedating role of alcohol. Implications are discussed.

The Effects of ß-myrcene on Simulated Driving and Divided Attention: A Double-Blind, Placebo-Controlled, Crossover Pilot Study.

Background: ß-myrcene, one of the most common terpenes found in cannabis, has been associated with sedation. We propose that ß-myrcene contributes to driving impairment even in the absence of cannabinoids. Aim: To conduct a double-blind, placebo-controlled crossover pilot study of the effect of ß- myrcene on performance on a driving simulator. Method: A small sample (n=10) of participants attended two experimental sessions, one in which they were randomized to receive 15 mg of pure ß-myrcene in a capsule versus a canola oil control. Each session, participants completed a baseline block and three follow-up blocks on a STISIM driving simulator. Results: ß-myrcene was associated with statistically significant reductions in speed control and increased errors on a divided attention task. Other measures did not approach statistical significance but fit the pattern of results consistent with the hypothesis that ß-myrcene impairs simulated driving. Conclusions: This pilot study produced proof-of-principle evidence that the terpene ß-myrcene, an agent commonly found in cannabis, can contributes to impairment of driving-related skills. Understanding how compounds other than THC affect driving risk will strengthen the field's understanding of drugged driving.

Cost-Effectiveness of Smoking Cessation Approaches in Emergency Departments.

INTRODUCTION: Americans of lower SES use tobacco products at disproportionately high rates and are over-represented as patients of emergency departments. Accordingly, emergency department visits are an ideal time to initiate tobacco treatment and aftercare for this vulnerable and understudied population. This research estimates the costs per quit of emergency department smoking-cessation interventions and compares them with those of other approaches. METHODS: Previously published research described the effectiveness of 2 multicomponent smoking cessation interventions, including brief negotiated interviewing, nicotine replacement therapy, quitline referral, and follow-up communication. Study 1 (collected in 2010-2012) only analyzed the combined interventions. Study 2 (collected in 2017-2019) analyzed the intervention components independently. Costs per participant and per quit were estimated separately, under distinct intervention with dedicated staff and intervention with repurposed staff assumptions. The distinction concerns whether the intervention used dedicated staff for delivery or whether time from existing staff was repurposed for intervention if available. RESULTS: Data were analyzed in 2021-2022. In the first study, the cost per participant was $860 (2018 dollars), and the cost per quit was $11,814 (95% CI=$7,641, $25,423) (dedicated) and $227 per participant and $3,121 per quit (95% CI=$1,910, $7,012) (repurposed). In Study 2, the combined effect of brief negotiated interviewing, nicotine replacement therapy, and quitline cost $808 per participant and $6,100 per quit (dedicated) (95% CI=$4,043, $12,274) and $221 per participant and $1,669 per quit (95% CI=$1,052, $3,531) (repurposed). CONCLUSIONS: Costs varied considerably per method used but were comparable with those of other smoking cessation interventions.

The prevalence of alcohol-involved crashes across high and low complexity road environments: Does knowing where drinking drivers crash help explain why they crash?

OBJECTIVE: Alcohol use has been linked to impairment of cognitive and psychomotor driving skills, yet the extent to which skill impairment contributes to actual crashes is unknown. A reasonable assumption is that some driving situations have higher skill demands than others. We contend that intersections, the presence of other vehicles or moving objects, and work zones are examples of common situations with higher skill demands. Accordingly, if skill deficits are largely responsible for alcohol-involved crashes, crashes involving a drinking driver (versus only sober drivers) should be overrepresented in these driving situations. METHOD: Publicly available FARS data from 2010 to 2017 were collected. Fatal crashes were coded as alcohol-involved (1+ driver with a blood alcohol concentration [BAC] ≥ .05 g/dl) or having no impaired driver (BACs = .000). Drug-positive crashes were excluded. Crashes were also coded as involving moving versus stationary objects, occurring at versus away from intersections, being multivehicle versus single vehicle, occurring at or away from work zones. RESULTS: Across multiple models, controlling for time of day and type of road, alcohol-involved crashes were significantly underrepresented in crashes at intersections, with moving objects, and other vehicles. Most strikingly, alcohol-involved crashes were 24 percentage points more likely to be with a stationary object than a moving object. CONCLUSIONS: No evidence supported the idea that skill reductions are a primary contributor to alcohol-involved crashes. Alternative explanations and limitations are discussed.

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.

Prevention of Alcohol and Other Drug Overuse Among Nightclub Patrons: A Randomized Trial of a Group-Based Mobile Intervention at Nightclubs.

OBJECTIVE: Electronic music dance events (EMDEs) at nightclubs attract young adults engaging in high-risk alcohol and other drug (AOD) use. Studies show that most patrons arrive at clubs in groups and that these peer groups influence drinking. Therefore, peer groups are a natural context for preventing risk behaviors. This article examined outcomes of a randomized controlled trial of a group-based mobile intervention at nightclubs, Nightlife Safety Plans (NSP). METHOD: The sample comprised 352 groups, consisting of 959 participants (45.3% female) at 41 events across seven nightclubs hosting EMDEs. Club patrons were surveyed anonymously and completed breath tests as they entered and exited clubs. Oral fluid samples collected from patrons at exit assessed drug use. Analyses examining assignment to NSP versus a control condition on fire safety predicted individual- and group-level protective strategy use and AOD use, controlling for background variables. RESULTS: At the individual level, participation in NSP was related to increased protective actions to keep group members safe. No effects were found on actions to keep oneself safe or in response to overuse. At the group level, assignment to NSP was related to a higher average number of group safety strategies. Participation in NSP was associated with lower blood alcohol concentration but unrelated to tetrahydrocannabinol and cocaine. CONCLUSIONS: NSP appears to be efficacious for increased protective actions to keep group members safe from overuse and for reduced blood alcohol concentration among EMDE patrons. The findings support the use of an intervention utilizing group-based strategies presented proximal to risk settings.

Impact of Group Cohesion Among Drinking Groups at Nightclubs on Risk From Alcohol and Other Drug Use.

Although protective strategies are implemented within drinking groups, alcohol and other drugs (AOD) use may increase when protective strategies are in place. Being in a cohesive group could lead to a false sense of security, leading to more risk taking. This study examines whether club patrons perceiving greater group cohesion implement fewer protective strategies and use more AOD. The sample includes 815 club patrons (44.2% female; M age = 27.7, SD = 6.0 years) arriving in 324 groups, from seven clubs hosting electronic music dance events, across 30 evenings. Anonymous surveys, biological measures of alcohol (entry and exit) and drugs (exit only), were used. Results show that group cohesion relates to fewer strategies to keep themselves and their group safe and fewer actions responding to group AOD problems. Group cohesion was unrelated to AOD use. Findings suggest that prevention strategies should incorporate influences of group cohesion in engaging patrons in group safety strategies at clubs.

The unintended effects of providing risk information about drinking and driving.

OBJECTIVE: Alcohol-impaired driving remains a serious public health concern despite the fact that drinking and driving risks are widely disseminated and well understood by the public. This research examines the motivational conditions under which providing risk information can exacerbate rather than decrease potential drinking drivers' willingness to drive while impaired. METHOD: In a hypothetical drinking and driving scenario, 3 studies investigated participants' self-reported likelihood of drinking and driving as a function of (a) accessibility of information regarding risk associated with drinking and driving, (b) motivation to drive, and (c) need for cognitive closure (NFC). RESULTS: Across the 3 studies, participants self-reported a higher likelihood of driving when exposed to high-risk information (vs. low-risk information) if they were high in NFC. Risk information did decrease self-reported likelihood of driving among low-NFC participants (Studies 1-3). Furthermore, this effect was exacerbated when the relevant motivation (to get home conveniently) was high (Study 3). CONCLUSIONS: These findings have important implications for impaired-driving prevention efforts. They suggest that at least under some circumstances, risk information can have unintended negative effects on drinking and driving decisions. The results are consistent with the motivated cognition literature, which suggests that people process and use information in a manner that supports their most accessible and important motivation despite potentially negative consequences. (PsycINFO Database Record

Social Drinking Groups and Risk Experience in Nightclubs: Latent Class Analysis.

Nightclubs are a setting in which young adults purposefully seek out experiences, such as drug use and alcohol intoxication that can expose them to physical harm. While physical harm occurs fairly frequently within clubs, many patrons have safe clubbing experiences. Further, not all patrons experience potential harms the same way, as there are differences in aggression and intoxication. In this article we draw on data from a research study in which we sought to better understand the role of social drinking groups in experiences of risk within nightclubs, as the majority of patrons attend with others. We collected data from 1,642 patrons comprising 615 social drinking groups as they entered and exited nightclubs in a major U.S. city. We focused on six experiences that might cause physical harm: alcohol impairment, alcohol intoxication, drug use, physical aggression, sexual aggression, and impaired driving. We aggregated patron responses across social groups and used latent class statistical analysis to determine if and how experiences tended to co-occur within groups. This analysis indicated there were five distinct classes which we named Limited Vulnerability, Aggression Vulnerability, Substance Users, Impaired Drivers and Multi-Issue. We assessed the groups within each class for distinctions on characteristics and group context. We found differences in the groups in each class, such as groups containing romantic dyads experienced less risk, while those groups with greater familiarity, greater concern for safety, and higher expectations for consumption experienced more risk. Group composition has an impact on the experiences within a club on a given night, in particular when it comes to risk and safety assessment.

Drinking group characteristics related to willingness to engage in protective behaviors with the group at nightclubs.

Electronic music dance events (EMDEs) in nightclubs are settings where young adults tend to engage in high-risk behaviors, such as heavy alcohol and drug use. Consequences of these behaviors may be prevented if young adults engage in protective strategies with their drinking group. It is important to identify drinking group characteristics that predict willingness to intervene with peers. Objectives of this study were to (a) examine whether young adults at EMDEs would be willing to intervene with members of their drinking group and (b) identify both individual and group characteristics of drinking groups that predict willingness to intervene. Nightclub patrons (N = 215 individuals; 80 groups) were surveyed anonymously as they entered clubs. Individual- and group-level characteristics were measured in relation to willingness to intervene with peers. Mixed-model regressions were conducted, accounting for nesting by drinking group. Analyses show that participants were willing to intervene with their peers. Groups that knew each other well and had lower expectations for members' drinking were more willing to intervene. Women, younger, and older participants were also more willing to intervene. Findings show that club patrons are willing to intervene with their drinking groups to protect them from harmful consequences of heavy drinking and drug use. Findings indicate characteristics of both individuals and drinking groups that could be targeted in interventions among young adults largely not being reached by college interventions.

A successful high-visibility enforcement intervention targeting underage drinking drivers.

AIMS: To measure the effectiveness of a high-visibility enforcement campaign to reduce rates of underage drinking and driving. DESIGN: Mixed-model analysis compares rates of drinking and driving (1) between the baseline and intervention period and (2) between the baseline and follow-up period. The impact of the intervention was evaluated using roadside surveys and web surveys. SETTING: Two college-town communities in the mid-Atlantic region of the United States. PARTICIPANTS: Study participants consisted of 6825 drivers stopped, interviewed and breathalyzed on weekend nights. Web survey data were collected from 2061 students from large state universities in each community. INTERVENTION: Increased high-visibility enforcement of drinking and driving laws, featuring the use of passive alcohol sensors by police, along with a coordinated publicity campaign. MEASURES: Roadside surveys measured breath alcohol concentrations (BrAC) of drivers. The web surveys measured self-reported drinking. FINDINGS: Mixed-model analysis revealed a statistically significant reduction in drivers with BrACs ≥ 0.08 g/dl during the intervention and follow-up periods, F(2, 5744)  = 6.5, P < 0.01. The web-survey revealed that students under age 21 also reported significantly less driving after drinking during the intervention and follow-up periods, F(2, 1767)  = 4.6, P < 0.01. CONCLUSIONS: A high-visibility enforcement campaign targeting underage drinking and driving appeared to reduce both underage driving after drinking among US college students as well as drunk driving (breath alcohol concentration ≥ 0.08 g/dl) at any age..

Night club patrons who feel safe will return: Evidence to encourage management to address club violence.

INTRODUCTION: There is substantial evidence that heavy drinking is associated with aggression and violence. Most managers of drinking establishments are required to maintain a security staff to deal with disruptive patrons who threaten an organization's business or legal status. However, managers may focus little on minor instances of aggression even though these may escalate into more serious events. We hypothesize that proactive security efforts may positively affect patrons' perceptions of nighttime safety and influence their decisions to return to the club, thereby affecting the club's bottom line. METHOD: Data for this study were collected from entry and exit surveys with 1714 attendees at 70 electronic music dance events at 10 clubs in the San Francisco Bay Area (2010-2012). Participants were asked to report on observations and experiences with aggressive behavior while in the club, their overall perception of club safety, and their plans to return to the same club in the next 30 days. Mediational multiple regression analysis was used to relate observations of club security to perceptions of personal safety and plans to return to the club. RESULTS: Reported observations of an active club security staff were positively related to perceptions of personal safety. Safety perceptions, in turn, were significantly related to plans to return to the club. The indirect path between perceptions of security and plans to return was significant as well. CONCLUSIONS: The results suggest that an active security presence inside clubs can encourage club attendance by providing an environment where minor altercations are minimized, contributing to the perception of club safety. PRACTICAL APPLICATIONS: Evidence that proactive security efforts appear to increase return customers might motivate managers to implement better security policies.

Enforcement uniquely predicts reductions in alcohol-impaired crash fatalities.

BACKGROUND AND AIMS: Alcohol-impaired driving contributes to more than 10 000 fatalities in the United States each year. This research estimated the unique effect of enforcement intensity on reductions in alcohol-impaired fatal crashes. DESIGN: We collected data from 30 states (including the District of Columbia) that experienced the greatest changes in alcohol-impaired fatal crashes from 1996 to 2006. Mixed-model regression was used to examine the extent to which year-over-year changes in the intensity of impaired driving enforcement predicted year-over-year reductions of drivers killed in alcohol-involved fatal crashes. SETTING: Data from 30 states were obtained online. PARTICIPANTS: Aggregate state-level data from a total of 279 state-year combinations were analyzed. MEASURES: Our dependent measure was the ratio of drivers involved in fatal crashes with blood alcohol concentrations (BACs) ≥ 0.08 g/dl over drivers involved in fatal crashes with BACs = 0.00 g/dl. Per capita driving under the influence (DUI) arrests and traffic enforcement funding were the primary predictors. Covariates were estimated vehicle miles traveled (VMT); the proportional distributions of gender and racial/ethnic; geographic distribution; the proportion of drivers aged 21-34 years; median family income; and education level. FINDINGS: Analysis revealed that DUI arrests per capita uniquely and significantly predicted reductions in the ratio of fatal crashes (ß = -0.753, t(238) = 2.1, P < 0.05) after controlling the covariates. Exploratory analysis suggests the increase in arrest rates was associated with stronger reductions in urban versus rural settings. CONCLUSIONS: Drunk driving enforcement intensity uniquely contributes to reductions in alcohol-impaired crash fatalities after controlling for other factors.

Clubbing With Familiar Social Groups: Relaxed Vigilance and Implications for Risk.

OBJECTIVE: This research examined the relationship between the intragroup familiarity among peers visiting nightclubs and the likelihood of experiencing negative outcomes. We hypothesized, based on our prior work, that members who are more familiar with their group would be more likely to experience sexual and physical aggression while at the club. METHOD: The study involved 1,765 young adults (within 654 natural groups) sampled at nightclubs in the San Francisco Bay area. Participants were interviewed about their clubbing history and expectations before entering the club and about their experiences in the club as they exited. Breath samples were collected at both entry and exit to obtain objective measures of alcohol use. RESULTS: Using generalized linear mixed modeling to accommodate correlated data, we found that, to the extent that club patrons were familiar with more of their peer group, the more likely they were to experience sexual and physical aggression, although this was moderated by participant gender. CONCLUSIONS: Although in many circumstances group cohesion can be a protective factor, the results of this study suggest that greater group familiarity might sometimes be associated with less concern for safety, reduced vigilance, and an increase in negative experiences.

Method of transportation and drinking among club patrons.

OBJECTIVE: The current study examines the variation in alcohol use among nightclub patrons under three transportation conditions: those who departed from a club using modes of transportation other than cars or motorcycles (e.g., pedestrians, bicyclists, subway riders); those who were passengers of drivers (auto/taxi passenger patrons); and those who drove from the club (driving patrons). We seek to determine whether patrons' choice for how to leave the club contributes to their risk, as assessed by blood alcohol concentrations (BAC), after controlling for other factors that may contribute to their BAC including demographic characteristics and social drinking group influences. METHODS: Data were collected from social drinking groups as they entered and exited clubs for 71 different evenings at ten clubs from 2010 through 2012. Using portal methodology, a research site was established proximal to club entrances. Each individual participant provided data on themselves and others in their group. The present analyses are based upon 1833 individuals who completed both entrance and exit data. Our outcome variable is blood alcohol content (BAC) based upon breath tests attained from patrons at entrance and exit from the club. Independent variables include method of transportation, social group characteristics, drug use, and personal characteristics. We use step-wise multiple regressions to predict entrance BAC, change in BAC from entrance to exit, and exit BAC: first entering individual demographic characteristics, then entering group characteristics, then drug use, and finally entering method of transportation (two dummy coded variables such that drivers are the referent category). RESULTS: In sum, in all three of our analyses, only three variables are consistently predictive of BAC: presence of a group member who is frequently drunk and non-driving modes of transportation, either being the passenger or taking alternate methods of transportation. In particular, taking an alternate form of transportation was consistently and strongly predictive of higher BAC. CONCLUSIONS: Additional public health messages are needed to address patrons who are no longer drinking and driving but who are nonetheless engaged in high levels of drinking that may lead to various risky outcomes, for example: being targeted for physical and/or sexual assault, pedestrian accidents, and other adverse consequences. These risks are not addressed by the focus on drinking and driving. Key messages appropriate for patrons who use alternate transportation might include devising a safety plan before entering the club and a focus on sobering up before leaving.

The impact of marijuana decriminalization on California drivers.

BACKGROUND: The liberalization of marijuana laws has led to concerns that such changes will increase "drugged driving" and crash-related mortality. California decriminalized marijuana effective January 1, 2011; we examine the impact of this change on marijuana-involved driving. METHODS: We used laboratory testing from roadside surveys and the Fatality Analysis Reporting System (FARS) to assess impacts on weekend nighttime drivers and fatally injured drivers, respectively. We calculated marijuana prevalence (measured by laboratory-confirmed delta-9-tetrahydrocannabinol [THC] in roadside surveys and cannabinoids in FARS) and compared corresponding 95% confidence intervals (CI) to identify statistically significant changes post-decriminalization. We also conducted multiple logistic regression analyses to determine whether the odds of marijuana-involved driving increased significantly after controlling for potential confounders. RESULTS: There was no statistically significant change in the prevalence of THC-positive driving among weekend nighttime drivers (n=894) in 2012 (9.2%; 95% CI: 6.3, 12.2) compared to 2010 (11.3%; 95% CI: 8.5, 14.0) or in the adjusted odds of testing positive for THC (adjusted odds ratio [AOR]=0.96; 95% CI: 0.57, 1.60). In contrast, we found a statistically significant increase in the prevalence of cannabinoids among fatally injured drivers in 2012 (17.8%; 95% CI: 14.6, 20.9) compared to the pre-decriminalization period 2008-2010 (11.8%; 95% CI: 10.3, 13.3). The adjusted odds of testing positive for cannabinoids were also significantly higher in 2012 (AOR=1.67; 95% CI: 1.28, 2.18). CONCLUSIONS: Our study generated discrepant findings regarding the impact of decriminalization on marijuana-involved driving in California. Factors that may have contributed to these findings, particularly methodological factors, are discussed.

Indicators of club management practices and biological measurements of patrons' drug and alcohol use.

BACKGROUND: Electronic music and dance events in nightclubs attract patrons with heavy alcohol/drug use. Public health concerns are raised from risks related to these behaviors. Practices associated with increased risk in these club settings need to be identified. OBJECTIVES: The relationship between club management practices and biological measures of patrons' alcohol/drug use is examined. METHODS: Observational data from 25 events across six urban clubs were integrated with survey data (N = 738 patrons, 42.8% female) from patrons exiting these events, 2010-2012. Five indicators of club management practices were examined using mixed model regressions: club security, bar crowding, safety signs, serving intoxicated patrons, and isolation. RESULTS: Analyses revealed that serving intoxicated patrons and safety signs were related to substance use. Specifically, serving intoxicated patrons was related to heavy alcohol and drug use at exit, while safety signs were marginally related to less exit drug use. CONCLUSIONS/IMPORTANCE: Findings indicate observable measures in nightclubs provide important indicators for alcohol/drug use, suggesting practices to target. Study strengths include the use of biological measures of substance use on a relatively large scale. Limitations and future directions are discussed.

Predicting DUI decisions in different legal environments: investigating deterrence with a conjoint experiment.

OBJECTIVE: Driving under the influence (DUI) enforcement practices and sanctions contribute differentially to the certainty, swiftness, and severity of punishment, which are the key components of general deterrence theory. This study used a conjoint experiment to understand the decision-making process of potential DUI offenders and tested how variation in enforcement and legal punishment affects drinking and driving decisions. It sought to verify and quantify the unique deterrent effects of certainty, severity, and swiftness and to predict the rates of drinking and driving in different legal environments. METHODS: One hundred twenty-one college seniors and graduate students at the University of Maryland participated in the Web-based conjoint experiment. They were randomly assigned to 4 blocks, each of which included 9 hypothetical scenarios composed of different levels of DUI enforcement and penalties. Respondents were asked to state their likelihood of drinking and driving under each scenario, as well as their estimated chance of being caught by the police for DUI. RESULTS: Intensified enforcement, harsh jail penalty, and immediate long license suspension were found to be the strongest deterrents to drinking and driving. Alternative ways to get home were also important in reducing people's willingness to drive. These factors accounted for most of the attribute effect on the DUI decision, whereas delayed punishment due to judicial processing, fine penalty, and legal blood alcohol concentration (BAC) limit had negligible effects. For the personal characteristics, college seniors and those who had previously driven after drinking were more likely to choose to drink and drive, whereas those who expect a jail penalty for a DUI offense were less likely to drive. CONCLUSIONS: Our research confirmed and quantified certainty of punishment as the greatest deterrent to DUI, but it also indicated the equally important effect of a severe jail penalty. It provides evidence on the feasibility of using a conjoint experiment in future studies to understand the general driver population and, with the help of a simulation tool, to predict DUI decisions in different legal environments. Such predictions can be used to better inform policy decisions on developing targeted general deterrence programs in different communities.

Assessment of club patrons' alcohol and drug use: the use of biological markers.

BACKGROUND: Young adulthood (ages 18-25 years) represents a time when high-risk behaviors, including alcohol and drug use, peak. Electronic music dance events (EMDEs) featured at clubs provide an ecologic niche for these high-risk behaviors. PURPOSE: This paper examines the prevalence of alcohol and drug use among EMDE patrons. Examination of personal characteristics associated with exit levels of alcohol and drug use identifies important indicators of risk taking for prevention strategies. METHODS: Data were collected anonymously during 2010-2012 from 2028 patrons as they entered and exited clubs in the San Francisco Bay area featuring EMDEs. Nearly half were aged ≤25 years. Biological measures of drug and alcohol and self-reported personal characteristics were attained. Analyses were completed in 2012. RESULTS: At entrance, more than one fifth of patrons were positive for drug use and one fourth arrived either impaired (blood alcohol concentration [BAC]: 0.05%-0.079%) or intoxicated (BAC: >0.08%) by alcohol. At exit, one fourth tested positive for drugs, and nearly half were impaired or intoxicated by alcohol. Individual characteristics that were important for levels of risk included prior alcohol use behaviors, sexual identity, ethnic/racial identity, and transportation to the event. Gender did not differentiate for alcohol use but fewer women used drugs. CONCLUSIONS: Findings confirm the importance of targeting EMDEs for prevention efforts. EMDEs attract young working adults who are engaged in heavy alcohol and/or drug use. Targeting these social settings for delivering public health prevention strategies regarding alcohol and drug use and related harm is indicated by the findings.