2007 National Roadside Survey of Alcohol and Drug Use by Drivers

2007 National Roadside Survey of Alcohol and Drug Use by Drivers: Drug ResultsTable 42. BAC Among Drug-Positive Drivers by Number of Drug Classes and Time of Day(Percentages Calculated by Row) (Oral Fluid)Time of DayDaytimeNighttimeBAC (g/dL)Number of Drug NBetweenClasses (Unweighted) Zero Zero and .08 .08+1 206 98.0% 1.6% 0.4%2+ 40 99.5% 0.5% 0.0%Overall Daytime 246 98.2% 1.4% 0.3%1 680 80.1% 14.7% 5.2%2+ 156 82.0% 17.0% 1.0%Overall Nighttime 836 80.5% 15.0% 4.5%In this table, percentages are weighted.When oral fluid drug category findings were combined with BAC results we found that, in boththe daytime and nighttime samples, the drug-positive drivers who were also alcohol-positivewere more likely to be positive for “Illegal” drugs than “Medications” (Table 43). This wasparticularly true in the nighttime sample, in which 17.3 percent had BACs between zero and .08(compared to 6.3% in the “Medications” category) and 5.7 percent had BACs greater than .08(compared to 1.2% in the “Medications” category) (p < .01). In the daytime sample, however, thedifferences were statistically non-significant (p value = .05).Table 43. BAC Among Drug-Positive Drivers by Drug Category and Time of Day (Oral Fluid)BAC (g/dL)Time ofNBetweenDay Drug Category (Unweighted) Zero Zero and .08 .08+Illegal 125 97.1% 2.3% 0.6%Daytime Medications 107 99.6% 0.4% 0.0%Illegal & Medications 14 98.3% 1.7% 0.0%Negative 1,604 99.2% 0.6% 0.2%Illegal 575 77.0% 17.3% 5.7%Nighttime Medications 199 92.5% 6.3% 1.2%Illegal & Medications 60 81.4% 17.7% 0.9%Negative 5,033 90.2% 8.1% 1.7%“Medications” includes prescription and over-the-counter drugs.In this table, percentages are weighted.Table 44 presents the findings by drug category, age, and time of day. Due to the number ofgroupings (and thus, relatively small sample sizes in included cells), caution should be exercisedin the interpretation of the findings, especially among the daytime driving sample. Overall,among the nighttime driving sample, the high alcohol-positive drivers (i.e., drivers registeringgreater than .08 BAC g/dL) tested positive for drugs in the “Illegal” category more frequentlythan “Medications” across all age groups except 65+ (an age group producing a very smallsample size for drug positives). Further, the same pattern emerged among drivers with BACs56