DWI Drivers Out in Force from 9 pm to 3 am;
Beer drinkers who bar hop are most dangerous says US Dept of Transportation

With respect to alcoholic beverage preference, studies dating back to the 1960s consistently have shown beer to be favored by a wide margin (Jones and Joscelyn, 1978; Jones and Lacey, 1989; Jones and Lacey, 1998a). Also, prior updates suggest that the drinking location preceding illegal drinking-driving was most frequently bars or taverns and other person’s homes. The 1998 update noted a study of New York State DWIs by Wieczorek, Miller, and Nochajski (1992b) that found that subjects who drank at more than one location engaged in DWI more often than did subjects who drank at only one location. The multiple-location DWIs had an average of 4.00 self-reported drunk driving events in the past 30 days compared to 2.46 for the single-location DWIs (p= 0.0009). In addition, the multi-location drinkers drove almost twice as far prior to their arrest (an average of 11.5 miles for multi-location versus 6.7 miles for single-location, p<0.0001 ), thereby exposing other drivers and their passengers to a greater crash risk. These two groups also differed significantly on a number of drinking variables, with the multi-location drinkers indicating patterns of heavier drinking and stronger evidence of alcohol problems and alcohol dependency.

The 1998 update also cited a study of Vermont university students by Musty and Perrine (1990) that found that some 70% of those under the legal drinking age reported drinking most frequently at private locations (for example, home, other person's homes, and clubs), and that about 75% of students above the legal drinking age reported drinking at public bars and restaurants.

Another study cited in 1998 update (Lang and Stockwell, 1991) examined the effect of type of drinking location on crash involvement in Australia. This study involved subjects in Perth, Australia who had been arrested for DWI, either as a result of being involved in a crash (n=257) or having failed a roadside sobriety test (n=1 ,909). Two types of drinking locations were considered in the study, "unlicensed" locations (for example, private residences or public places such as parks) and "licensed" locations. The study found that the prior drinking location of the drivers whose DWI arrest occurred after a crash was more likely to be an unlicensed location than it was for drivers whose DWI arrest occurred after some other event or activity such as speeding or reckless driving (p=0.001). Thirteen percent of the drivers who drank in an unlicensed location were arrested after a crash compared to 8% of the drivers who drank in a licensed location. Note that these figures reflect the conditional probability of an arrest given a crash, not the unconditional probability of crash.

Since the 1998 update, additional literature has appeared considering the interaction of drinking location, beverage type, and other factors, including biographical factors. Especially noteworthy is a study by Gruenewald and associates (2000). The study sought to determine whether the association of beer drinking with drinking and driving is due to cultural norms or is an artifact arising from the demographic profile of beer drinkers (young and male), the drinking patterns of this sub-population (frequent and heavy), and the venues in which they prefer to drink (bars and restaurants). The data were obtained from a carefully designed telephone survey in six U.S. communities involving a test sample that included 2,275 drinkers, 985 of whom had driven after drinking.

The study found that frequent consumers were more likely to drink outside the home, preferred beer and spirits to wine, and were more likely than others to drink and drive. Most important, beverage preferences were not directly associated with drinking and driving. Beer drinkers, however, were from the sub-population most likely to drink and drive, heavier drinking younger men, who prefer ro drink at bars and restaurants. The results suggested that the association of beer consumption with drinking-driving arises from the circumstances in which the subpopulation of beer drinkers more commonly find themselves (as a result of their efforts to maximize, within economic constraints, the social and amenity value of drinking), as opposed to any culturally induced disposition beer drinkers may have to drink and drive.

Three recent studies in New Mexico have examined the the role of drinking location in drinking-driving. In the first study, Chang, Lapham , and Barton (1996) compiled the sociodemographic characteristics of 5,154 mostly male DWI offenders) referred for alcohol-related assessment. They found that some groups showed a higher rate of DWI convictions, compared to the adult county population, that is: young, single male; Hispanic and Mexican National; and divorced/separated/widowed (increasing with age). They also found that older, educated or employed offenders reported drinking more in bars or lounges, while younger offenders were more likely to drink in private parties. Further, Hispanic and Mexican National men showed equal likelihood of drinking with friends and relatives in bars or lounges, whereas non-Hispanic White males reported drinking more with friends. Native Americans were associated with higher blood alcohol concentrations (BAC), and with alcohol-related problems.

Lapham, Skipper, Chang et al. (1998) estimated the distance driven between drinking and arrest locations among 3,107 New Mexico offenders convicted of DWI and determined whether the drinking location, the driver's appearance (factors such as race, age, gender), or age of the vehicle accounted for any differences in the estimated distance driven. Among those who were not arrested in the immediate vicinity, the number of miles driven ranged from 0.5 to 18.2, with a mean of 3.4 miles (median= 2.6). Further, persons who drank in a high or medium-high arrest intensity area, those with BACs of .20+, and those drinking at bars, restaurants, or private parties, drove fewer miles compared to other offenders. The authors also found that factors such as age, gender, and vehicle age were unrelated to how far drunk drivers travel before their arrests.

In the third study of New Mexico DWIs, Lewis, Lapham, and Skipper (1998) examined alcohol purchase locations of convicted drunk drivers to determine the characteristics and arrest circumstances of offenders who bought alcohol at a drive-up liquor window compared with those who obtained alcohol elsewhere. The study results revealed that drive-up windows were the preferred place of purchase of package liquor by offenders who bought the alcohol that they drank prior to arrest. The odds of being Hispanic (p<0.0001), a high-risk problem drinker (p<0.01), and drinking in the vehicle prior to arrest (p<0.01) were significantly higher for drive-up window users than for offenders who purchased package liquor elsewhere. The authors concluded that a statistically significant relationship exists between the use of drive-up windows and "certain high-risk drinking behaviors."

Jones-Webb, Toomey, Short et al. (1997) examined relationships among perceived alcohol availability, drinking location, alcohol consumption, and drinking problems. Their subjects were 3,372 adolescent drinkers, ages 16-18, who participated in the authors’ Communities Mobilizing for Change on Alcohol Project baseline survey (See page 132). The authors found that perceived alcohol availability was significantly associated with higher levels of alcohol consumption for males. Drinking in a public location, such as a bar, restaurant, or party, was marginally associated with higher levels of alcohol consumption for females.

Greenfield and Rogers (1999) examined effects of measurement on risk curve analysis in an application involving prediction of frequency and indicator measurements of drunk driving with beverage-specific alcohol consumption and risk perception measures. Again, self-reported data were used, this time from a 1995 household survey in which the responses of 1,260 adult drivers who reported any drinking in the prior year were selected for analysis. Relationships between drinking pattern, beverage choice, perception of risks and drinking before driving, and frequency of drunk driving, were investigated. Self-reported drunk driving (occurrence) was measured by a question assessing driving after drinking enough to be in trouble if stopped by the police within the prior 12 months, and those affirming this (n = 191) were asked how many times they did so.

It was found that, after controlling for demographics, heavy beer consumption (p < .01) more than heavy wine (not significant) or liquor / spirits (p < .05) intake was strongly predictive of risk perception. A significant interaction was found between heavy beer consumption and perceived risk (p < .001) in predicting reported frequency of drunk driving. The authors concluded that individuals' underestimation of beer's intoxicating effects, compared to other alcoholic beverage types, helps explain beer's over-representation in drinking-driving violation reports.

The same authors (Rogers and Greenfield, 1999) generalized their findings on beer drinking to "hazardous drinking" in general, which they defined as occasions in which five or more drinks were consumed in a day. Their data came from a survey involving 2,817 respondents who had consumed at least one drink in the previous year. The results showed that, in the U.S., beer accounts for the bulk of alcohol consumed by the heaviest drinkers and that beer also accounts for a disproportionate share of hazardous drinking. Logistic regression analysis revealed that drinkers who consumed beer in a hazardous fashion at least monthly are more likely to be young, male, and unmarried and less likely to be Black than are other drinkers. Hazardous beer consumption was found to be more predictive of alcohol-related problems than hazardous consumption of wine or spirits.

A wide range of epidemiologic and clinical studies have clearly indicated the over-involvement of persons with drinking problems in drinking and driving incidents, including alcohol-related traffic crashes as well as arrests and convictions for DWI. Many of these studies are reviewed in prior updates.

Several recent studies have examined the relationship between BAC at arrest and alcohol problems. Lapham, Chang, Skipper et al. (2000) studied the association between arrest blood alcohol concentration (BAC) and alcohol use disorders among convicted drunk driving offenders in New Mexico. Subjects were interviewed using the Diagnostic Interview Schedule, discussed in Chapter 2. If the age at onset of alcohol disorders was the same as or younger than the age at screening, the person was classified as having alcohol abuse or dependence at the time of screening. Arrest BAC ranged from .01 to .45 (mean = .156). Alcohol dependence at screening was found for 58% of offenders with BAC <.15, 66% of offenders with BAC .15 to .19, and 72% of offenders with BACs of .20 or above (p<.001). The overall accuracy of BAC of .15 or higher and .20 and higher as a screening test for alcohol dependence ranged from .45 to .64. The authors concluded that, although arrest BAC is associated with alcohol use disorders, it provides limited utility as an objective indicator of alcohol dependence.

Bergman, Hubicka, Laurell et al. (2000) assessed 1,600 Swedish drivers suspected of DUI, and a control group of 785 drivers not suspected of DUI using the Alcohol Use Disorders Identification Test (AUDIT) instrument. The authors found that hazardous or harmful alcohol use according to the AUDIT was four times as common among the male, and ten times among the female, suspected DUIs, as compared to the control drivers. Further, more than half (58%) of the suspected DUIs had such drinking problems and 18% had severe problems. Also, almost half (46%) of the suspects with a BAC below the Swedish illegal limit of .02 had such problems. This lead the authors to conclude that BAC level has low sensitivity and specificity as a means for identifying drinking problems in suspected DUIs.

Wieczorek, Miller, and Nochajski (1992a) had arrived at similar conclusions after examining the relationship between BAC at arrest and a number of variables related to drinking patterns and alcohol abuse or dependence¹⁷. Their sample consisted of 235 persons convicted of DWI and referred to a drinking driver treatment program in Erie County, New York. BACs at arrest were available for all of these subjects, and only those with a BAC greater than .05 were included in the study. Data were collected through face-to-face interviews, clinical evaluations, and the complete Mortimer-Filkins test. None of the results indicated any significant relationship between BAC at arrest and diagnoses of alcohol problems. Significance levels were 0.40 for all but one of the tabulated analyses, the clinical analysis (p>0.10), which indicated that the high-BAC group (BAC > .15) had slightly fewer non-critical alcohol problems.

However, Lucker and Gold (1995) obtained different results in a study of the association between breath alcohol concentration (BAC) at arrest and problem drinking for a sample of 1,283 male DWI offenders in the U.S. Army. The results indicated a moderate but statistically significant association between BAC at arrest and DSM-III diagnosis. BAC's ability to indicate problem drinking was also compared with the diagnostic ability of three well-known, paper-and-pencil instruments designed for that purpose. BAC performed as well in identifying problems with alcohol as did the MAST, the MacAndrew Scale of the MMPI, and the Vaillant.

Hutchinson (2000) conducted in depth interviews with a sample of 48 male convicted drink drivers, all drinking 50+ units per week. An analysis of their drinking patterns and styles showed that there is a wide range of drinking patterns and styles and no consistency. He found that drinking patterns vary over the years, from occasional to daily drinking, and are altered by major lifestyle changes. Likewise drinking styles had no consistency but there was a concentration on separating drinking from work-related activities. The quantity consumed on any or each drinking occasion bore no relation to either pattern or style of drinking. The author concluded that the only controlling device is the concept of "alcoholic," and that there is no safe or sensible limits as such.

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