Alcohol‐Impaired Driving and Perceived Risks of Legal Consequences

Iimpaired driving have codied DWI as criminal behavior,enforcing laws, and legislating sanctions for convictedALCOHOLISM: CLINICAL AND EXPERIMENTAL RESEARCH Vol. *, No. * 2017Alcohol-Impaired Driving and Perceived Risks of LegalConsequencesFrank A. Sloan, Sabrina A. McCutchan, and Lindsey M. EldredBackground: Driving while impaired (DWI) is a threat to public health. Codied legal sanctions area widely implemented strategy to reduce DWI. However, it is unclear that sanctioning aects individualrisk perceptions so as to deter alcohol-impaired driving.Methods: Using survey data collected from individual drivers, police, and defense attorneys special-izing in DWI in 8 U.S. cities, we investigated whether risk perceptions about legal consequences foralcohol-impaired driving, both the risk of being stopped if driving while alcohol-impaired and receivingspecic penalties following a DWI, deter alcohol-impaired driving. First, we analyzed how dierentdrivers risk perceptions about being pulled over and facing criminal sanctions related to their self-reported alcohol-impaired driving in the year following the interview at which risk perceptions were eli-cited. Second, using data from an experimental module in which individuals risk perceptions were ran-domly updated by the interview, we analyzed how each drivers beliefs about his or her own futurealcohol-impaired driving responded to randomly generated increases in the apprehension probabilityand sanction magnitude.Results: Higher probabilities as estimated by the individuals of being pulled over corresponded toless alcohol-impaired driving in both analyses. Conversely, there was no statistical relationship betweenperceptions of criminal sanctions for DWI and alcohol-impaired driving with 1 exceptiona small sig-nicant negative relationship between duration of jail time following a DWI conviction and alcohol-impaired driving.Conclusions: Perceptions regarding the threat of being apprehended for alcohol-impaired drivingwere related to actual self-reported driving, while perceived sanctions following a DWI conviction forDWI generally were unrelated to either actual self-reported alcohol-impaired driving or the personsestimate of probability that he or she would drive while alcohol-impaired in the following year. Increas-ing certainty of apprehension by increasing police stang and/or conducting sobriety checks is a moreeective strategy for reducing alcohol-impaired driving than legislating increased penalties for DWI.Key Words: Driving While Impaired, Risk Perceptions, Deterrence, Sanctions, Police.N 2015, ALCOHOL-impaired drivers caused over 10,000trac fatalities in the United States, comprising 20% ofall trac fatalities (National Highway Trac Safety Admin-istration, 2016). Drinking substantially increases driversaccident risk, even at blood alcohol content levels below thethreshold of 0.08% that denes criminal driving whileimpaired (DWI) (Phillips et al., 2015). Over 110 million alco-hol-impaired driving episodes occur annually (Bergen et al.,2011).Society has traditionally relied on the legal system toachieve criminal deterrence. Attempts to deter alcohol-From the Department of Economics (FAS, SAM, LME), DukeUniversity, Durham, North Carolina.Received for publication August 12, 2016; accepted November 18,2016.Reprint requests: Frank A. Sloan, PhD, Department of Economics,Duke University, 213 Social Sciences Building, Box 90097, Durham, NC27708; Tel.: 919-613-9358; Fax: 919-684-8974; E-mail:Copyright 2017 by the Research Society on Alcoholism.DOI: 10.1111/acer.13298Alcohol Clin Exp Res, Vol *, No *, 2017: pp 111oenders. Sanctions include minimum nes, jail sentences,drivers license suspensions/revocations, and secure continu-ous remote alcohol monitoring (SCRAM) and ignition inter-lock devices (Lawrence, 2013; Voas and Fisher, 2001).Studies examining how statutory sanctions relate to alcohol-involved accident rates and self-reported alcohol-impaireddriving have yielded inconsistent results (Ahlin et al., 2011;Ferguson, 2012; Hansen, 2015; Kaufman and Wiebe, 2016;Nagin and Pogarsky, 2001; Sloan et al., 1994; Wagenaar andMaldonado-Molina, 2007; Wagenaar et al., 2007; Whetten-Goldstein et al., 2000). In contrast, studies on enforcementhave consistently found a relationship between increasedenforcement and reductions in alcohol-impaired driving(Erickson et al., 2015; Fell et al., 2014, 2015; Sanem et al.,2015). Fell and colleagues (2014), for example, reported thata 10% increase in the DWI arrest rate corresponded to a 1%reduction in alcohol-involved accidents.One explanation for the mixed results on sanction eec-tiveness may be that many studies have omitted risk percep-tions. Sanctions act as deterrents to the extent that theyinuence individuals risk perceptions (Erickson et al., 1977;Kleck et al., 2005; Nagin, 1998; Pogarsky et al., 2004).There are many possible reasons risk perceptions mightnot align with sanctions in statutes. First, an individual may12lack knowledge about statutory provisions for alcohol-impaired driving. Lack of knowledge of objective risks canlead to risk misperceptions (Sloan et al., 2013). Second,actual sanctioning practices may deviate from statutoryguidelines because prosecutors and judges have substantialdiscretion in applying laws, including the use of plea bargains(Bibas, 2016; Grin et al., 2013; Ross, 1982). Risk percep-tions may more closely align with actual risks than with sta-tutes if based on actual experiences of individuals themselvesand others. Studies have shown that individuals lacking per-sonal experience with the legal system tend to have higherrisk estimates, but these adjust closer to objective risk reali-ties as experience is gained (Dionne et al., 2007; Horney andMarshall, 1992; Nagin, 1998). Third, other inuences such asindividual dierences in criminal propensity, preferences forcertain types of sanctions over others, and situational factorsshape risk perceptions (Nagin and Paternoster, 1993; Woodand May, 2003).SLOAN ET AL.their actual self-reported alcohol-impaired driving behaviorsduring the year after the risk perceptions were elicited. Sec-ond, using data from an experimental module in which indi-viduals risk perceptions were randomly updated by theinterview, we analyzed how each drivers beliefs about his orher own future alcohol-impaired driving responded to ran-domly generated increases in the apprehension probabilityand sanction magnitude. We found that perceptions regard-ing the threat of being apprehended for alcohol-impaireddriving were related to actual self-reported alcohol-impaireddriving. Those who perceived a higher risk of being appre-hended were less likely to drive while alcohol-impaired.However, perceived sanctions following a conviction forDWI generally were unrelated to either actual self-reportedalcohol-impaired driving or the persons estimate of proba-bility that he or she would drive while alcohol-impaired inthe following year.Another explanation for discrepant ndings is that dier-ent studies have examined dierent dimensions of risk per-ceptions. Risk perceptions about consequences of criminal Data SourcesMATERIALS AND METHODSbehavior may be dierentiated into beliefs about the cer-tainty of apprehension and the certainty, severity, and swift-ness of punishment (Gibbs, 1975). Certainty iscomparatively more important than severity or swiftness indecision making (Grogger, 1991; Lochner, 2007; Nagin,2013). Prior studies on risk perceptions of alcohol-impaireddriving have shown that certainty of apprehension and ofpunishment, that is, sanctioning, have deterrent eects, whilebeliefs about sanction severity are less inuential (Alonsoet al., 2015; Beck et al., 2009; Dionne et al., 2007; Lanza-Kaduce, 1988; Nagin and Pogarsky, 2001).This study used data from the Survey on Alcohol andDriving (SAD) and interviews with attorneys and lawenforcement ocers to evaluate how risk perceptions ofapprehension and sanctions inuenced self-reported alcohol-impaired driving. All interviews were conducted for ourstudy. Other studies of risk perceptions and alcohol-impaireddriving also utilized survey data, but mostly with smallersamples and samples limited to students at a given university(Lanza-Kaduce, 1988; Nagin and Paternoster, 1993; Naginand Pogarsky, 2001; Yao et al., 2014). An exception isDionne and colleagues (2007), a study based on a survey of2,857 adult license holders in Quebec.Our study used a sample of over 1,000 potential adult drin-ker-drivers in 8 U.S. cities spanning 4 geographically dis-persed states. These data were supplemented with data frominterviews of defense attorneys practicing DWI law and lawenforcement ocers who were asked to report the probabili-ties of apprehension and sanctioning and sanction levels forDWI in the 8 study cities. As these attorneys were experi-enced in how the law was actually applied in these cities, theinterviews elicited information on actual legal practices notsimply data from statutes.We employed 2 analytical approaches. First, we examinedhow dierent individuals risk perceptions were related toSurvey on Alcohol and Driving. The SAD measured risk percep-tions of legal consequences for alcohol-impaired driving and otheroutcomes in a population of potentially impaired drivers. Surveyquestions were modeled after similar previous surveys designed tomeasure risk perceptions. We identied potential alcohol-impaireddrivers by screening for individuals who had both driven and con-sumed at least 1 drink within the last 30 days. Respondents wereadults aged 18 to 81 from 8 cities: Raleigh and Hickory, North Car-olina (NC); Philadelphia and Wilkes-Barre, Pennsylvania (PA);Seattle and Yakima, Washington (WA); and Milwaukee and LaCrosse, Wisconsin (WI). These 4 states were selected to provide vari-ation in DWI arrest rates, criminal laws pertaining to DWI, alcoholconsumption, and demographic composition. Within each state,further variation was introduced by surveying persons from a largeand a small city. The longitudinal nature of the SAD allowed us tomeasure actual self-reported alcohol-impaired driving behavior ininterviews conducted a year after risk perceptions were elicited.Battelle Memorial Institute conducted the SAD in 3 waves fromlate 2009 to early 2012. The rst wave of SAD interviews was con-ducted by telephone. This wave elicited information on sociodemo-graphic characteristics, alcohol-related behaviors, health, cognition,impulsivity, and other types of information. After screening, 1,634persons completed the rst wave. The second and third waves wereconducted by computer-assisted self-administered interviews(CASI). The second wave (CASI-I) elicited subjective beliefs aboutrespondents future alcohol-impaired driving and current legal con-sequences for DWI. The third wave (CASI-II) was administered ayear after CASI-I. This wave repeated selected batteries of questionsfrom CASI-I and also asked respondents to report their number ofactual alcohol-impaired driving episodes since the CASI-I interview.The CASI-I and CASI-II interviewed 1,359 and 1,187 persons,respectively. Both CASI waves contained experimental questionswhich allowed us to analyze how randomly increased probabilitiesand increased levels of dierent sanctions related to the respondentsbeliefs that they would engage in alcohol-impaired driving in thefollowing year.Law Enforcement Ocer Interviews. In 2010, research assistantsat Duke University surveyed law enforcement ocers employed bymunicipal police, state highway patrol, and county sheri depart-ments in 7 of the 8 study cities. Philadelphia law enforcement agen-cies declined to participate. Ninety-two law enforcement ocersALCOHOL-IMPAIRED DRIVING RISK, CONSEQUENCESrepresenting 11 dierent agencies were interviewed. Ocers wereasked to estimate the probability of being apprehended when driv-ing alcohol-impaired in their jurisdiction. We expected ocers tohave expert knowledge of how impaired driving laws were enforced.Questions about apprehension were phrased analogously to theircounterparts in the SAD.Attorney Interviews. The same research assistants also con-ducted interviews of defense attorneys practicing DWI law in the 8cities. We screened attorneys who regularly practiced DWI law byinterviewing those representing 12+ DWI cases in the previousyear, yielding 62 interviews. Attorneys were asked to provide infor-mation about their legal practices and to estimate the probabilitiesand levels of specic sanctions being imposed following a convictionfor DWI. As in interviews with law enforcement, questions aboutsanctions were phrased analogously to SAD questions to facilitatecomparison. All questionnaires were reviewed approved by DukeUniversitys Institutional Review Board (IRB) and the SAD by Bat-telles IRB as well.Sample ConstructionThree analysis samples were constructed from SAD data. Theconstruction of these samples was determined by how respondentsanswered selected survey questions. Because the way a question isframed may aect the response (Lumsdaine and Exterkate, 2013),the SAD elicited risk perceptions using questions phrased in thethird and then in the second person. To illustrate, respondents wererst asked: “What is the percent chance that a person would receivea ne after being convicted of DWI?” In the analogous second-per-son question, “a person” was replaced with “you.” All respondentswere asked about risk perceptions using third-person language, butonly respondents who said there was some chance they would bepulled over for suspected alcohol-impaired driving in the next yearwere asked questions in the second person.The rst and largest analysis sample, hereafter Sample L, con-sisted of individuals who provided risk perceptions of legal conse-quences in response to all third-person questions (N = 1,079). Thesecond analysis sample, Sample M, consisted of individualsresponding to all second-person questions about risk perceptions.As almost half of CASI-I respondents said there was no chance theywould be apprehended for alcohol-impaired driving in the next year,Sample M was thus substantially smaller (N = 537). The module ofexperimental questions that asked respondents to estimate their sub-jective probability of future alcohol-impaired driving in response torandomly increased apprehension probabilities and sanction levelswas posed exclusively in the second person, and hence only adminis-tered to individuals in Sample M. The third analysis sample, SampleS, consisted of individuals who answered experimental questions inboth CASI waves (N = 444). The observational unit in the analysisbased on Sample S was each individuals response. Each individualprovided an estimate in both waves, for a total of 888 observations2 per respondent.Empirical SpecicationWe specied 3 dependent variables. First, a count variable mea-sured the number of self-reported alcohol-impaired driving episodes(phrased as driving “after having had too much to drink”) in theyear between CASI-I and II. Respondents reported their number ofepisodes using response categories of 0, 1, 2, 3 to 4, and 4 times.We coded responses of 3 to 4 as 3.5 and 4 as 7. The open-endedcategory represented 5.4 and 9.9% of responses in samples L andM, respectively. The second dependent variable was a binary forany alcohol-impaired driving between the 2 CASI waves. The thirddependent variable, used in Sample S regressions, was an individ-uals estimate of the probability of driving alcohol-impaired at least3once in the year following the CASI-I survey given a randomlyincreased apprehension probability or sanction level.Key explanatory variables were risk perceptions of 5 legal con-sequences for alcohol-impaired driving: apprehension probability,expected values of the following 4 sanctionsnes (in $100s), jailsentences (in weeks), drivers license suspensions/revocations, andSCRAM/ignition interlock devices (in months). The way thesevariables were dened diered. In the rst analysis, where weexamined how dierent respondents risk perceptions were relatedto their self-reported alcohol-impaired driving, the key explana-tory variables were for the respondents perceptions of apprehen-sion probability and of 4 sanctions, elicited at the CASI-Iinterviews. The SAD asked each respondent what probability andlevel of a given sanction he or she perceived. In the analysis, wemultiplied the probability and corresponding sanction level toobtain the expected value of that sanction. Regressions based onSample L used third-person questions for these explanatory vari-ables, while regressions based on Sample M used second-personquestions.In the second analysis, where we examined how an individualsestimated probability of future alcohol-impaired driving changed inresponse to experimentally varied apprehension risks and sanctionlevels, the key explanatory variables were 5 experimentally variedlegal consequences. We only varied sanction levels, not sanctionprobabilities, so the 4 sanction covariates in regressions based onSample S were sanction levels and not expected sanction values. Arespondents risk perceptions elicited at CASI-I were multiplied byrandomly generated values greater than 1 to yield new legal conse-quences of alcohol-impaired driving. In both CASI waves, multipli-ers were selected independently for each respondent and each legalconsequence. We asked respondents about 1 legal consequence at atime, for example, “If the ne for DWI were $550, what is the per-cent chance you would drive after drinking too much in the nextyear?” By doing so, we implicitly directed respondents to updatetheir perceptions of that variable while holding other variables con-stant.While the focus of this study was on risk perceptions of legal con-sequences for alcohol-impaired driving, we controlled for risk per-ceptions of 1 nonlegal outcome: increased accident risk. Specically,the SAD asked: “If you drank