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Technology Transfer Series

Number 269, March 2002


Whether it's Thursday, Friday, or Saturday night, 2 out of 3 UNC students return home with a .00 BAC. The National Highway Traffic Safety Administration (NHTSA) sponsored a study by the Highway Safety Research Center (HSRC) of the University of North Carolina to develop a program to reduce drinking and impaired driving on a college campus.

During the 1990s, several national telephone surveys documented that drinking was widespread among college students in the United States. These surveys and other studies also documented a variety of undesirable consequences of student drinking. In addition to deaths and injuries resulting from motor vehicle crashes, college students increase their risk of injury as pedestrians, in falls, and in fires. Alcohol use also contributes to interpersonal violence, including sexual assault, and academic problems.

Despite all the reports they have heard about student alcohol use, the researchers found that the norm for alcohol use among college students is actually moderation rather than excess at the University of North Carolina.

Nighttime Surveys Collect BACs

HSRC used a unique approach. They conducted a nighttime survey where randomly selected students provided breath samples to measure their blood alcohol concentration (BAC) levels. During the fall of 1997, BAC measurements were obtained from 1,786 students as they returned home to residence halls, fraternity and sorority houses, and off-campus apartments between 10 p.m. and 3 a.m.

A different picture emerged from the earlier self-report surveys. Although 23 percent of students had been drinking, high BACs were relatively uncommon - 11 percent of the students had a BAC above .08 and less than 2 percent were above .15. On Thursdays, Fridays, and Saturdays, the traditional party nights, 65 percent of students returned home with a .00 BAC.

It is clear that heavy drinkers believe they are the norm on campus, whereas lighter, less frequent drinkers, despite being in the distinct majority, believe they are atypical.

Social Norms Approach Used to Develop Message

Students overestimate the amount of drinking at college. The norm for alcohol use among UNC college students is actually moderation rather than excess. The social norms approach to reducing excessive drinking focuses on helping individuals recognize the reality of student drinking. It is informative and focuses on the entire student body.

Because the actual amount of drinking and, therefore, normative drinking are less than believed, simply persuading all students to understand the misperception should reduce pressures to drink for those who are light or non-drinkers. The simple facts about student drinking provide social support for those who don't drink or who drink occasionally and lightly, since they are in the clear majority. At the same time, this information should help remove the perceived social support for the behavior of those who drink frequently and heavily, since they are a small minority.

Program Focuses on First Year Students

After testing several messages, a basic message was chosen that was clear and easily understood by students: Whether it's Thursday, Friday, or Saturday night, 2 out of 3 UNC students return home with a .00 BAC. The program initially focused on first year students who are just finding their niche on campus in hopes of preventing them from developing the same misperceptions about drinking that characterize older students.

This information about the true alcohol use norm was given to incoming students and their parents at orientation sessions. An incentive campaign using posters and stickers delivered the program to the entire student population. There was a chance for students to win cash if they correctly knew the "2 out of 3" alcohol fact. A news conference spread the message throughout the campus community and beyond. Periodic ads in the student newspaper drew attention to the alcohol fact and to the incentive program.

Survey Repeated in 1999

Two years later, HSRC repeated the BAC survey during the fall of 1999. They measured student alcohol use again and awareness of the "2 out of 3" program of a sample of 2,535 students. Of the first year students, 92 percent were aware of the program; 71 percent of all students were aware of it. Of those who had heard of the program, 70 percent understood the fact to mean that drinking is less common or that pressure to drink is less than is typically believed.

A substantial proportion of students (54 percent) did not believe that "2 out of 3" accurately portrayed student drinking. This skepticism may be another indicator of the widespread existence of misperceptions about college student drinking. Those who did not believe that "2 out of 3" is an accurate representation of UNC are the more extreme drinkers, not merely drinkers or occasional heavy drinkers. Belief in the accuracy of "2 out of 3" is related to the number of drinking nights and heavy drinking (more than 5 drinks) nights during the past two weeks. Looking at measured drinking and acceptance of the "2 out of 3" fact, those who had a BAC above .08 when they were interviewed were more skeptical than those with a lower or .00 BAC (68 vs 53 percent).

BAC Measurements Show Drinking Declined

The proportion of students with a BAC above .08 declined from 10.7 to 8.3 percent, a statistically significant decline of 22 percent. Student incidents involving alcohol also declined in association with the "2 out of 3" program. Self-reported drinking did not change from the earlier survey.

Changes in Impaired Driving

Changes in the BACs of persons who reported they had driven (or were interviewed as drivers) showed the same decrease found among students in general. Drivers with a BAC of .08 or higher declined from 2.6% to 1.3% and students with any measurable alcohol decreased from 13% to 9.7%. These decreases were not statistically significant, however, due to the small sample size of drivers (n=302).

Program Materials

The report includes detailed information about how the program was developed, the messages tested, comprehensive data and data collection procedures, program materials, posters, stickers, interview questionnaires, web site and media marketing plans.


For a copy of Development and Evaluation of a Comprehensive Program to Reduce Drinking and Impaired Driving Among College Students, write to the Office of Research and Traffic Records, NHTSA, NTS-31, 400 Seventh Street, S.W., Washington, DC 20590; or send a fax to (202) 366-7096. Patty Ellison-Potter, Ph.D., was the contract manager.

U.S. Department
of Transportation
National Highway
Traffic Safety

400 Seventh Street, S.W. NTS-31
Washington, DC 20590

Traffic Tech is a publication to disseminate information about traffic safety programs, including evaluations, innovative programs, and new publications. Feel free to copy it as you wish.

If you would like to receive a copy contact:

Linda Cosgrove, Ph.D., Editor, Evaluation Staff
Traffic Safety Programs
fax (202) 366-7096