Methods

Readers are referred to the National Survey of Drinking and Driving Attitudes and Behaviors: 1997 (Balmforth, 1997) report for a fully detailed description of the research methods used.

The sampling objective of each of the study waves was to acquire a representative national sample of the general driving age public (age 16 and older). A telephone survey was used to reach the target population and to provide national estimates of attitudes and behaviors regarding drinking and driving.

A two-stage procedure was used to meet the sampling objective by first selecting a sample of working residential telephone numbers in the U.S. (both listed and unlisted residential telephone households) with an equal probability of selection. The second stage involved a random selection of a single respondent from all eligible members of driving age residing in each selected household using the "most recent birthday" method.

Multiple attempts were made to reach each randomly selected respondent. Up to seven attempts were made to reach the household, and once a respondent in the household was identified, up to seven additional attempts were made to reach that person.

While the original three studies included responses from persons age 16 and older, this analysis highlights the findings of persons age 16 to 64. The following numbers of telephone interviews with persons age 16 to 64 were conducted each administration:

Interviewing for each administration took place in the Fall (generally between October and December of the study year). Interviews were completed in both English- and Spanish-language, using a computer-assisted-telephone interviewing (CATI) system.

The final telephone samples of persons age 16 and older were independently weighted using a four-stage weighting procedure to equalize selection probabilities (at both the household and the individual levels) and to adjust for non-response bias by matching the profile of surveyed respondents to the known demographic profile of the U.S. population 16 to 64.

The goal of this analysis was to identify the differences in attitudes and behaviors of different racial and ethnic groups. NHTSA was interested in analyzing the differences between groups of persons who are of White, Black, Asian, American Indian and Hispanic origin. Since the data were weighted to U.S. Census Bureau estimates, and the Census defines race separately from ethnicity, the following questions were used to identify the race and ethnicity of the respondents:

1 ETHNICITY:   Are you of Hispanic origin?



2 RACE:   Which of these categories best describes your racial background? White, Black or African American, Asian or Pacific Islander, Eskimo Aleutian or American Indian or some other?

While Hispanic is viewed as an ethnicity descriptor rather than a race, and is thus mutually exclusive to race, for the purposes of this analysis, the goal was to look at comparisons of the five groups. Thus, the following categorization was used to achieve a single race/ethnic categorization:

If a respondent noted that they were both Hispanic and Asian or American Indian/Eskimo, the race of the respondent (Asian, American Indian/Eskimo) took precedence over ethnicity (Hispanic). The number of combined interviews by race/ethnicity of person age 16-64 across the three administrations appear below:

 

 

Precision of Sample Estimates

All sample surveys are subject to sampling error in that results may differ from what would be obtained if the whole population had been interviewed. The size of such sampling error depends largely on the number of interviews as well as other factors such as the complexity of the sample design. For this sample of 10,453 persons age 16-64, the expected maximum sampling error range is approximately +/- 1.0% at the 95% level of confidence.

Due to the stratification and other complexities of the sample design, in some cases (particularly among smaller sub-groups of the population), the error ranges will be slightly larger than those shown in the table will. The table above shows the sampling error ranges by race and at the 95% level of confidence for the entire combined sample. This information is provided to offer the reader a general sense of the range of the true estimates. In many instances data is not available for all three administrations, or survey questions were asked of only a subset of the population (e.g. drinking-drivers). True error ranges can be calculated using advanced statistical procedures (such as SUDAAN) using the actual survey data which is available through NHTSA.

Data Presented

The study examines the results from the three combined survey administrations in the following chapters:

	Drinking and Driving Behaviors
	Perceptions of Drinking and Driving as a Problem
	Prevention and Intervention
	Enforcement of Drinking and Driving Laws
	Knowledge and Awareness of BAC Levels and Legal Limits
	Motor Vehicle Crash and Injury Experience

Attempts were made to show the above data for each of the five racial/ethnic groups. However in some instances data are not available for all three administrations (as a number of key questions were added in the 1995 administration), or survey questions were asked of only a subset of the population (e.g. drinking-drivers). In such instances, the racial/ethnic categories may be condensed further to compare Whites, Blacks and Other, or White, Black, Hispanic, Other where sample sizes allow. It should be noted that the precision of the estimates for these analyses is lower than those noted above for the full sample. To help aid in the assessment of sampling error precision, the sample size of presented subgroups is presented for each data chart.

The following table shows the overall measures of drinking and driving used as bases throughout this report.

Race/Ethnicity

	Total	White	Black	Asian	American Indian/Eskimo	Hispanic
Driver, past year	94%	97%	84%	89%	90%	87%
Drinker, past year	65%	69%	49%	46%	60%	56%
Problem drinker	13%	13%	13%	11%	40%	23%
Drinking-drivers, past year	26%	28%	16%	13%	21%	17%

 

 

The following definitions are used throughout this report:

Drinking-Drivers or Drinker-drivers: persons who drove within 2 hours of consuming alcohol

Other drivers who drink: persons who drank alcohol in the past year, and who drove in the past year, but have not driven within two hours of consuming alcohol

Problem drinkers: "Problem drinkers" are defined as those who meet at least ONE of the following three conditions:

1. Said "yes" to two or more of the "CAGE" measures;
   "Have you felt you should cut down on your drinking?" ("C" for "cut down");
   "Have people annoyed ("A") you by criticizing you about your drinking?";
   "Have you felt bad or guilty ("G") about your drinking?";
   "Have you had a drink first thing in the morning to steady your nerves or get rid of a hangover?" ("E" for "eye-opener").
   
   
2. Consumed five or more drinks on four or more days in a typical four-week period; or
   
   
3. For females, consumed eight or more drinks on a given day in the past four weeks, or for males, consumed nine or more drinks on a given day in the past four weeks.

   (Ewing, 1984; Skinner and Holt, 1987)

It should be noted that problem drinkers are not by definition drinker-drivers, as they may not drive after consuming alcohol.

Trip: a single occasion a person drove a motor vehicle

Drinking-driving trip: a trip in which a person drove a motor vehicle within two hours of consuming alcohol

BAC (Blood Alcohol Concentration) Estimate V (calculated using the following formula):

compute mass=bodwgt/2.2046.

if sex=1 waterpc=.58.

if sex=2 waterpc=.49.

metabac=(qn39+(qn41/60)-1)*0.012.

compute waterkg=mass*waterpc.

compute alcoz=qn38*.045.

compute alcml=alcoz*23.36.

compute alcg=alcml*.806.

compute alckg=alcg/100.

if waterkg>0 estbac=100*(alckg/waterkg).

if estbac deltabac=estbac-metabac.

if deltabac<0 deltabac=0.

Where: bodwgt=weight in pounds

sex=1-male 2-female

qn39=time spent drinking (in hours)

qn41=time from last drink to drive (in minutes)

qn38=number of drinks consumed

 

 

 

 

Modified Tuesday, November 02, 2010 Copyright @ 2010 by Fathers' Manifesto & Christian Party