Amy Berning

Alcohol- and drug-involved driving in the United States: methodology for the 2007 National Roadside Survey.

This article describes the methodology used in the 2007 U.S. National Roadside Survey to estimate the prevalence of alcohol- and drug-impaired driving and alcohol- and drug-involved driving. This study involved randomly stopping drivers at 300 locations across the 48 continental U.S. states at sites selected through a stratified random sampling procedure. Data were collected during a 2-hr Friday daytime session at 60 locations and during 2-hr nighttime weekend periods at 240 locations. Both self-report and biological measures were taken. Biological measures included breath alcohol measurements from 9,413 respondents, oral fluid samples from 7,719 respondents, and blood samples from 3,276 respondents.

Drinking and driving in the United States: comparing results from the 2007 and 1996 National Roadside Surveys.

Objectives: The objectives of this study were to (a) use data from the 2007 National Roadside Survey (NRS) to determine the characteristics of weekend nighttime drivers with positive blood alcohol concentrations (BACs) on U.S. roads in 2007; (b) determine the relationship of the driving environment and trip characteristics associated with drinking drivers; and (c) compare the findings for the 2007 NRS with those for the 1996 NRS. Methods: Like the 1996 NRS, the 2007 NRS used a stratified random national roadside survey sample of the contiguous 48 states and collected nighttime data on Fridays and Saturdays between 10 p.m. and 3 a.m. Officers directed 8384 drivers into off-road parking areas where our research team asked them to participate in the survey. Results: Of those approached, 7159 (85.4%) provided a breath test. Results revealed that 12 percent of the nighttime drivers had positive BACs, and of those, 2 percent were higher than the 0.08 BAC illegal limit in the United States. Since the 1996 NRS, we found significant reductions in the percentage of BAC-positive drivers across different demographic groups. Age was among the most significant factors associated with a weekend driver having a positive BAC. The probability that a driver would be drinking peaked in the 21- to 25-year-old age group. Male drivers were more likely than female drivers to be drinking, and Asian and Hispanic drivers were less likely than white drivers to be drinking. Drinking drivers were more likely to be driving short distances (5 or fewer miles) late at night (between 1 and 3 a.m.) and to be coming from a bar or restaurant. Finally, 26 percent of the drivers who reported that they would drive less than 5 miles on the night of the survey had positive BACs, compared to only 16 percent who indicated that they would drive between 6 and 20 miles and 10 percent who planned to drive more than 20 miles. Conclusions: The 2007 NRS provides another benchmark in the 4-decade record of drinking drivers on American roads and provides a basis for measuring progress in combating driving under the influence during the coming decade.