Predicting DUI recidivism of male drunken driving: a prospective study of the impact of alcohol markers and previous drunken driving

Effectiveness of road safety interventions: An evidence and gap map

Background

Road Traffic injuries (RTI) are among the top ten leading causes of death in the world resulting in 1.35 million deaths every year, about 93% of which occur in low- and middle-income countries (LMICs). Despite several global resolutions to reduce traffic injuries, they have continued to grow in many countries. Many high-income countries have successfully reduced RTI by using a public health approach and implementing evidence-based interventions. As many LMICs develop their highway infrastructure, adopting a similar scientific approach towards road safety is crucial. The evidence also needs to be evaluated to assess external validity because measures that have worked in high-income countries may not translate equally well to other contexts. An evidence gap map for RTI is the first step towards understanding what evidence is available, from where, and the key gaps in knowledge.

Objectives

The objective of this evidence gap map (EGM) is to identify existing evidence from all effectiveness studies and systematic reviews related to road safety interventions. In addition, the EGM identifies gaps in evidence where new primary studies and systematic reviews could add value. This will help direct future research and discussions based on systematic evidence towards the approaches and interventions which are most effective in the road safety sector. This could enable the generation of evidence for informing policy at global, regional or national levels.

Search Methods

The EGM includes systematic reviews and impact evaluations assessing the effect of interventions for RTI reported in academic databases, organization websites, and grey literature sources. The studies were searched up to December 2019.

Selection Criteria

The interventions were divided into five broad categories: (a) human factors (e.g., enforcement or road user education), (b) road design, infrastructure and traffic control, (c) legal and institutional framework, (d) post-crash pre-hospital care, and (e) vehicle factors (except car design for occupant protection) and protective devices. Included studies reported two primary outcomes: fatal crashes and non-fatal injury crashes; and four intermediate outcomes: change in use of seat belts, change in use of helmets, change in speed, and change in alcohol/drug use. Studies were excluded if they did not report injury or fatality as one of the outcomes.

Data Collection and Analysis

The EGM is presented in the form of a matrix with two primary dimensions: interventions (rows) and outcomes (columns). Additional dimensions are country income groups, region, quality level for systematic reviews, type of study design used (e.g., case-control), type of road user studied (e.g., pedestrian, cyclists), age groups, and road type. The EGM is available online where the matrix of interventions and outcomes can be filtered by one or more dimensions. The webpage includes a bibliography of the selected studies and titles and abstracts available for preview. Quality appraisal for systematic reviews was conducted using a critical appraisal tool for systematic reviews, AMSTAR 2.

Main Results

The EGM identified 1859 studies of which 322 were systematic reviews, 7 were protocol studies and 1530 were impact evaluations. Some studies included more than one intervention, outcome, study method, or study region. The studies were distributed among intervention categories as: human factors (n = 771), road design, infrastructure and traffic control (n = 661), legal and institutional framework (n = 424), post-crash pre-hospital care (n = 118) and vehicle factors and protective devices (n = 111). Fatal crashes as outcomes were reported in 1414 records and non-fatal injury crashes in 1252 records. Among the four intermediate outcomes, speed was most commonly reported (n = 298) followed by alcohol (n = 206), use of seatbelts (n = 167), and use of helmets (n = 66). Ninety-six percent of the studies were reported from high-income countries (HIC), 4.5% from upper-middle-income countries, and only 1.4% from lower-middle and low-income countries. There were 25 systematic reviews of high quality, 4 of moderate quality, and 293 of low quality.

Authors' Conclusions

The EGM shows that the distribution of available road safety evidence is skewed across the world. A vast majority of the literature is from HICs. In contrast, only a small fraction of the literature reports on the many LMICs that are fast expanding their road infrastructure, experiencing rapid changes in traffic patterns, and witnessing growth in road injuries. This bias in literature explains why many interventions that are of high importance in the context of LMICs remain poorly studied. Besides, many interventions that have been tested only in HICs may not work equally effectively in LMICs. Another important finding was that a large majority of systematic reviews are of low quality. The scarcity of evidence on many important interventions and lack of good quality evidence-synthesis have significant implications for future road safety research and practice in LMICs. The EGM presented here will help identify priority areas for researchers, while directing practitioners and policy makers towards proven interventions.

Subsequent risky driving behaviors, recidivism and crashes among drivers with a traffic violation: A scoping review

PURPOSE

Drivers who have committed a traffic violation are a particularly high-risk group, yet studies conducted among this group are scarce. We analyzed and synthesized the current literature concerning subsequent risky driving behaviors, recidivism, and crashes among drivers with a traffic violation.

METHODS

We searched PubMed, Education Resources Information Center (ERIC), Academic Search Complete, Web of Science, and Scopus for articles published in English between January 1, 1999, and May 31, 2023. A total of 25 articles met the selection criteria and were included in the final analysis. Two coders independently extracted and analyzed the selected articles to identify common categories across the articles, including study design, study population, type of traffic violation, and study outcomes including subsequent driving behaviors, recidivism, and crash risks.

RESULTS

Of the 25 selected articles, 19 (76%) involved both male and female participants. Fourteen (56%) studies were interventions/evaluation studies, with the other 11 (44%) being observational. Nineteen (76%) studies included alcohol-impaired driving violations, and 23 (92%) studies examined recidivism as an outcome measure. Over half of the observational studies demonstrated that traffic offenders were more likely to commit a subsequent traffic violation or had elevated risk of crashes. Most of the intervention/evaluation studies demonstrated a significant reduction in driving under the influence (DUI) of alcohol among the study participants. However, such positive effects observed during the active intervention period were not always sustained.

CONCLUSIONS

Traffic offenders are a high-risk group for subsequent violations and crashes. Evidence from this review calls for more effective interventions implemented following a traffic violation to prevent recidivism, crashes, and crash-related injuries and deaths.

New evidence of high association between carbohydrate deficient transferrin (CDT) and alcohol-related road traffic accidents. A retrospective study on 929 injured drivers

BACKGROUND

It is well known that traffic injuries still represent one of the main causes of death and that high blood alcohol concentrations while driving significantly increase the occurrence of accidents. However, only limited literature on the correlation between chronic alcohol abuse and accident risk is available. The aim of the present study was to investigate the hypothesis of an association between elevated concentrations of carbohydrate deficient transferrin (CDT) and the occurrence of alcohol-related traffic accidents.

METHODS

The analytical determinations of BAC and CDT were performed following certified methods in HS-GC-FID and HPLC, respectively. For BAC, 0.50 g/L was used as cut-off, whereas 2.0% was used for CDT, according to the standardisation proposed by IFCC. A total of 929 drivers, tested for BAC at the time of hospital admission after a traffic accident, were classified into two groups: InjDr 1 (BAC ≤ 0.50 g/L) and InjDr 2 (BAC>0.50 g/L); all drivers were also tested for CDT.

RESULTS

InjDr 1 included 674 individuals, only 2.5% showing a CDT above the cutoff, whereas InjDr 2 group consisted of 255 subjects, 28.6% testing positive for CDT (Odds Ratio 15.5). When subdividing the InjDr group into increasing classes of CDT, a steady increase in the percentage of BAC-positive drivers was appreciated. Moreover, average BAC was found to parallel each class of CDT.

CONCLUSIONS

The reported data strongly support the use of CDT as a biomarker of increased risk of alcohol-related traffic accidents in the procedures of re-granting of the driving license upon confiscation for "drink driving".

Critical Evaluation of the Association Between Elevated Mean Corpuscular Volume and Alcohol-Related Traffic Accidents: A Retrospective Study on 6244 Car Crash Cases

BACKGROUND

Erythrocyte mean corpuscular volume (MCV) has been used for decades as a biomarker of chronic alcohol abuse and in the treatment of alcohol dependence. More recently, it has also been adopted to investigate the fitness of subjects to hold the driving license to prevent traffic accidents. So far, however, the studies on the association of MCV with an increased risk of alcohol-associated car accidents are extremely scarce, if not totally absent. To the best of our knowledge, the present work is the first specifically aimed at studying a plausible association between elevated MCV and crash accidents correlated with alcohol abuse.

METHODS

A total of 6,244 drivers involved in traffic accidents underwent mandatory laboratory analyses including blood alcohol concentration (BAC) determination and MCV analysis. BAC and MCV determinations were performed by headspace gas chromatography and complete blood count, respectively.

RESULTS

The chi-square test evaluating the proportions of subjects with elevated MCVs (>95 fl) yielded a highly significant result (χ²  = 68.0; p < 0.001) in the blood samples where the BAC was above the legal limit (i.e., >0.5 g/l). However, when considering only drivers showing BACs in the range of 0.51 to 1.5 g/l, the frequencies of elevated MCV values are fairly comparable (χ²  = 0.062, p = 0.80). In contrast, limiting the evaluation to BACs > 1.5 g/l, the frequency of elevated MCVs raised to 19.1% (χ²  = 58.9, p value < 0.001 vs. the group with BAC within the legal limits).

CONCLUSIONS

The present observations show that MCV increases are typically associated with drivers involved in accidents only if driving under severe alcohol intoxication, leading to a preliminary conclusion that, in the context of the certification of the fitness to the driving license, MCV fails to reveal individuals at risk who tend to drive in a condition of low-to-moderate alcohol intoxication.

Improved recovery of repeat intoxicated drivers using fingernails and blood spots to monitor alcohol and other substance abuse

OBJECTIVES

This study reports the results of a pilot program in Kenosha County that used a combination of direct biomarkers extracted from blood spots and nails to monitor repeat intoxicated drivers for their use of alcohol and drugs with a detection window spanning from 3 weeks to several months. The objectives were to test whether the direct biomarkers phosphatidylethanol (PEth), ethylglucuronide (EtG), and 5 drug metabolites would (1) help assessors obtain a more objective evaluation of repeat offenders during the assessment interview, (2) allow for timely identification of relapses and improve classification of drivers into risk categories, and (3) predict recidivism by identifying offenders most likely to obtain a subsequent operating while intoxicated (OWI) offense within 4 years of enrollment in the program.

METHODS

All (N = 261) repeat offenders were tested using PEth obtained from blood spots and EtG obtained from fingernails; 159 participants were also tested for a 5 drugs of abuse nail panel. Drivers were tested immediately after the assessment interview (baseline) and at 3, 6, 9, and 12 months after baseline. Based on biomarker results and self-reports of abstinence, offenders were classified into different risk categories and required to follow specific testing timelines based on the program's decision tree.

RESULTS

The baseline analysis shows that 60% of drivers tested positive for alcohol biomarkers (EtG, PEth, or both) at the assessment interview, with lower detection rates (0-11%) for the 5 drug metabolites. The comparison of biomarkers results to self-reports of abstinence identified 28% of all offenders as high risk and assigned them to more frequent testing and more intense monitoring. The longitudinal analysis shows that 56% (completers) of participants completed the program successfully and the remaining 44% (noncompliant) terminated prematurely. Two thirds (68%) of the completers were able to reduce or control their drinking and one third relapsed at least one time during their mandated monitoring periods. After a brief intervention by the assessors, 79% of relapsers tested negative for biomarkers in their repeat tests. The rearrest analysis showed that offenders classified in the noncompliant and relapsers groups were 7 times more likely to receive a new OWI 4 years after enrollment compared to drivers classified as abstainers or controllers. Refractory drivers were monitored the longest and reported no subsequent rearrests.

CONCLUSION

These findings demonstrate the benefits of more individualized interventions with repeat OWI offenders and calls for further development of multimodal approaches in traffic medicine including those that use direct alcohol biomarkers as evidence-based practices to reduce recidivism.

Cognitive and behavioral preoccupation with alcohol in recidivist DUI offenders

OBJECTIVE

A high proportion of individuals convicted of driving under the influence (DUI) are repeat offenders. Efforts have sought to identify specific factors underlying DUI recidivism. Of particular interest is the role that alcohol-related cognitions might play in the development and escalation of alcohol use. The present study investigated the degree to which preoccupation with, and attentional bias to, alcohol are heightened among repeat DUI offenders.

METHOD

Three groups of participants (recidivist DUI offenders, first-time offenders, and controls; n = 20 per group) performed a visual probe task to measure attentional bias and completed questionnaires regarding their cognitive and emotional preoccupation with alcohol and drinking habits.

RESULTS

Recidivist offenders displayed a significantly heightened alcohol attentional bias and reported greater preoccupation with alcohol compared with both first-time offenders and controls. By contrast, none of the groups differed with regard to the self-reported quantity and frequency of their consumption.

CONCLUSIONS

Factors reflecting preoccupation with alcohol have utility for differentiating recidivist offenders from both first-time offenders and nonoffenders. These findings highlight the value of moving beyond self-reported assessments of drinking patterns toward assessing specific cognitive and behavioral characteristics that can improve our understanding, assessment, and treatment of the problem of DUI recidivism.

Factors associated with recurrence of alcohol-related traffic violations in southern Brazil

OBJECTIVE

To analyze variables associated with recurrence of blood alcohol content (BAC)-related traffic violations among drivers in southern Brazil.

METHOD

This cross-sectional study included 12,204 driving-under-the-influence (DUI) offenders according to data provided by the Rio Grande do Sul state Transportation Department. Sociodemographic characteristics, license duration, license category, and psychological assessment results were analyzed. Drivers convicted of DUI more than once in 2009/2010 were considered recidivists. Variables were evaluated using descriptive statistical analysis and Poisson regression, adjusted by sex, age, and education level.

RESULTS

A total of 538 (4.41%) drivers were considered recidivists. The following variables showed the strongest associations with recidivism: being aged 41-50 years (prevalence ratio [PR] = 3.41), being licensed for ≥ 12 years (PR = 1.86), being licensed for motorcycles, cars and trucks (PR = 1.36), having a license with psychological restrictions (PR = 1.33), and driving a truck or a similar vehicle at the moment of notification (PR = 1.08).

CONCLUSIONS

In the age group with the highest risk for recurrence, drivers showed a higher probability of having a diagnosis of alcohol dependence and other psychiatric comorbidities that hinder the control of alcohol use. Psychological assessments seem to be important in predicting repeat offenses, especially when limited aptitudes are suspected, and should therefore be better investigated.

Usefulness of indirect alcohol biomarkers for predicting recidivism of drunk-driving among previously convicted drunk-driving offenders: results from the recidivism of alcohol-impaired driving (ROAD) study

AIM

In several European countries, drivers under the influence (DUI), suspected of chronic alcohol abuse are referred for medical and psychological examination. This study (the ROAD study, or Recidivism Of Alcohol-impaired Driving) investigated the usefulness of indirect alcohol biomarkers for predicting drunk-driving recidivism in previously convicted drunk-driving offenders.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

The ROAD study is a prospective study (2009-13) that was performed on 517 randomly selected drivers in Belgium. They were convicted for drunk-driving for which their licence was confiscated. The initial post-arrest blood samples were collected and analysed for percentage carbohydrate-deficient transferrin (%CDT), transaminsase activities [alanine amino transferase (ALT), aspartate amino transferase (AST)], gamma-glutamyltransferase (γGT) and red cell mean corpuscular volume (MCV). The observation time for each driver was 3 years and dynamic.

FINDINGS

A logistic regression analysis revealed that ln(%CDT) (P < 0.001), ln(γGT) (P < 0.01) and ln(ALT) (P < 0.05) were the best biochemical predictors of recidivism of drunk-driving. The ROAD index (which includes ln(%CDT), ln(γGT), -ln(ALT) and the sex of the driver) was calculated and had a significantly higher area under the receiver operator characteristic curve (0.71) than the individual biomarkers for drunk-driving recidivism. Drivers with a high risk of recidivating (ROAD index ≥ 25%; third tertile) could be distinguished from drivers with an intermediate risk (16% ≤ ROAD index < 25%; second tertile; P < 0.001) and a low recidivism risk (ROAD index < 16%; first tertile; P < 0.05).

CONCLUSIONS

Of all routinely used indirect alcohol markers, percentage of carbohydrate-deficient transferrin is the major predictor of recidivism of drunk-driving. The association with gamma-glutamyltransferase, alanine amino transferase and the sex of the driver could have additional value for identifying drunk-drivers at intermediate risk of recidivism. Non-specific indirect alcohol markers, such as alanine amino transferase, gamma-glutamyltransferase, aspartate amino transferase and red cell mean corpuscular volume have minimal added value to % carbohydrate-deficient transferrin for distinguishing drunk drivers with a low or high risk of recidivism.

Commentary: why is the odds ratio for involvement in serious road traffic accident among drunk drivers in Norway and Finland higher than in other countries?

OBJECTIVE

Recent Norwegian and Finnish studies have found high odds ratios for serious or fatal injury in road traffic accidents among drivers after drinking alcohol. In this report we have compared the odds ratios with results from studies in other countries.

METHODS

A literature review was conducted.

RESULTS

The odds ratios were significantly higher than in countries where drunk driving is more common.

CONCLUSION

The calculated odds ratios are not only related to alcohol use or blood alcohol concentration per se but also related to the study design-for example, the inclusion of nonculpable drivers among cases-and confounding factors not included in statistical analysis; for example, risk-taking behavior. Those two issues may contribute to explaining why the reported odds ratios are higher for Norway and Finland.

Attitudes do matter: The role of attitudes and personality in DUI offenders

Several studies have related personality variables with antisocial behavior. Among antisocial behaviors, driving under the influence (DUI) has received growing attention in recent years, particularly in relation to the role of personality. However, it has been shown that personality alone is not sufficient to accurately predict DUI. As a result, there is growing interest in identifying other types of individual differences that might predict this behavior better, such as attitudinal variables. The aim of this study was to examine differences in personality dimensions and attitudes between a group of DUI offenders and a comparison group. Ninety-eight subjects were assessed: 51 subjects who had been convicted of a DUI offense following a diversion program, and 47 drivers without criminal records. Personality was measured with the NEO-Five Factor Inventory (NEO-FFI) and antisocial attitudes were assessed with the Jesness Inventory-Revised. Results indicated that offenders were more prone to show antisocial attitudes (p<.001) than comparisons. In terms of personality, there were no significant differences between the two groups. These findings suggest that attitudes may be useful predictors of DUI and should be taken into account in interventions designed to avoid recidivism.

Addiction research centres and the nurturing of creativity: the Department of Alcohol, Drugs and Addiction at the National Institute for Health and Welfare in Finland: diverse problems, diverse perspectives

The Department of Alcohol, Drugs and Addiction started operations on 1 January 2009, when the National Institute of Public Health (KTL) and the National Research and Development Centre for Welfare and Health (STAKES) were merged. The newly formed institute, called the National Institute for Health and Welfare (THL), operates under the Finnish Ministry of Social Affairs and Health. The scope of the research and preventive work conducted in the Department covers alcohol, drugs, tobacco and gambling issues. The two main tasks of the Department are (i) to research, produce and disseminate information on alcohol and drugs, substance use, addictions and their social and health-related effects and (ii) to develop prevention and good practices with a view to counteracting the onset and development of alcohol and drug problems and the damaging effects of smoking and other addictions. The number of staff hovers at approximately 60 people. The Department is organized into three units, one specialized in social sciences (the Alcohol and Drug Research Unit), another in laboratory analytics (the Alcohol and Drug Analytics Unit) and the third primarily in preventive work (the Addiction Prevention Unit). These units incorporate a rich variety and long traditions of both research and preventive work. The mixture of different disciplines creates good opportunities for interdisciplinary research projects and collaboration within the Department. Also, the fact that in the same administrative context there are both researchers and people specialized in preventive work opens up interesting possibilities for combining efforts from these two branches. Nationally, the Department is a key player in all its fields of interest. It engages in a great deal of cooperation both nationally and internationally, and among its strengths are the high-quality, regularly collected long-term data sets.

What non-alcohol drugs are used by drinking drivers in Sweden? Toxicological results from ten years of forensic blood samples

INTRODUCTION AND METHOD

Using a forensic toxicology database (TOXBASE), the toxicological results from 10 years of forensic blood samples from people arrested for driving under the influence of alcohol and/or other drugs were reviewed.

RESULTS

Alcohol was the only drug identified in blood in N=35,704 cases at a median blood-alcohol concentration (BAC) of 1.63 mg/g. The mean age (±SD) of these offenders was 40±15years and 89% were male. The median BAC was lower (1.30 mg/g) in drivers who had consumed alcohol and used a prescription drug before driving (N=1,251). The mean age of this group of traffic offenders was 38±13years and 85% were male. Both the median BAC (0.97 mg/g) and the mean age were lowest (36±11years, 92% male) in N=3,153 drivers who had consumed alcohol and used illicit drugs before driving. Cannabis, amphetamine, cocaine and morphine (metabolite of heroin) were the commonest illicit drugs identified in blood samples. Sedative-hypnotics (benzodiazepines) were the major prescription drugs co-ingested with alcohol. Poly-drug use was a common finding in these traffic delinquents, although individuals who only drank alcohol had a higher median BAC and were also several years older than drinking drivers combining alcohol with other drugs before driving.

IMPACT ON INDUSTRY

Zero-tolerance legislation did not deter hard-core offenders. In future there should be more focus on treatment for alcohol and substance abuse disorder rather than conventional punishments for this type of traffic crime.

Decision-making capacities and affective reward anticipation in DWI recidivists compared to non-offenders: a preliminary study

OBJECTIVES

Impaired decision making is seen in several problem behaviours including alcoholism and problem gambling. Decision-making style may contribute to driving while impaired with alcohol (DWI) in some offenders as well. The Somatic Marker Framework theorizes that decision making is the product of two interacting affective neural systems, an impulsive, rapid, amygdala-dependent process for emotionally signalling the immediate negative or positive consequences of an option, and a reflective, longer-lasting, ventral medial prefrontal cortex dependent system for emotionally signalling the future negative or positive prospects of an option. This study tested the hypothesis that offenders who showed disadvantageous decision-making would be at higher risk for recidivism than those who showed more advantageous decision-making. In addition, in line with the Somatic Marker Hypothesis, offenders who showed disadvantageous decision-making would exhibit a distinct pattern of somatic activation compared to offenders who showed more advantageous decision-making.

METHODS

A sample of 21 DWI offenders with from 2 to 7 past DWI convictions and a reference group consisting of 19 non-offender (N-O) drivers were recruited and administered the Iowa Gambling Task (IGT), as well as evaluated on sociodemographic, driving and alcohol use dimensions. In addition, anticipatory skin conductance response (aSCR) was measured in the 5s prior to each of a 100 card draws on the IGT.

RESULTS

Median split of the DWI offender sample based upon overall performance on the IGT yielded two subgroups (IGT-R Hi and IGT-R Lo). Hypothesis 1 was supported, as the IGT-R Lo group possessed significantly greater frequency of past DWI convictions and severity of past drinking. Descriptive analyses revealed that on the IGT, IGT-R Hi group performed similarly to the N-O reference group while the IGT-R Lo group performed significantly worse. Hypothesis 2 was not supported.

CONCLUSIONS

Decision making is a plausible explanatory neurocognitive pathway to severer forms of DWI. The role of emotional processing in DWI risk is uncertain. Subtyping DWI offenders using neurocognitive criteria seems a promising avenue for improving clinically meaningful methods of DWI risk assessment and intervention.

Detection of phosphatidylethanol (PEth) in the blood of drivers in an alcohol ignition interlock program

OBJECTIVE

The rate of failed interlock blood alcohol content (BAC) tests is a strong predictor of recidivism post-interlock and a partial proxy for alcohol use. Alcohol biomarkers measured at the start of an interlock program are known to correlate well with rates of failed BAC tests over months of interlock use. This study evaluates 2 methods of measuring low blood levels of the biomarker phosphatidylethanol (PEth). PEth is a 100 percent alcohol-specific biomarker and strongly intercorrelated with several independent indicators of drinking driving risk, including 8 other biomarkers, 3 psychometric assessments, and the rate of failed interlock BAC tests during many months of interlock use. Does a more sensitive method of measuring PEth at program entry detect drinking even among those who subsequently log no failed interlock tests?

METHODS

In a sample of 281 driver blood samples, PEth was measured by both high-performance liquid chromatography (HPLC) and liquid chromatography tandem mass spectrometry (LCMSMS) in order to compare sensitivity and accuracy. The average rate of failed interlock BAC tests was the criterion measure for marker sensitivity. LCMSMS, calibrated to detect low levels of drinking as a possible measure of abstinence violation, was judged relative to the standard HPLC assay for PEth measured up to 4 μmol/L.

RESULTS

The 2 methods showed a good quantitative relationship (r(2)> .86). LCMSMS detected positive PEth levels in samples that were below the limit of detection of the HPLC method. PEth measured by LCMSMS was positive for a higher proportion of driving under the influence (DUI) offenders who logged zero failed interlock BAC tests than were detected by HPLC.

CONCLUSION

Although HPLC is the widely used standard for measuring PEth in clinical alcoholism samples, the LCMSMS method, when calibrated to detect trace amounts of the major component of PEth, can detect abstinence levels of alcohol near zero intake and still correlate strongly with other indicators related to alcohol use and road safety.