Driving, Drinking, and Drug Use

21. Prevalence of Alcohol Use Among Drivers in US

"The 2007 NRS found a dramatic decline in the number of drinking drivers with BACs [Blood Alcohol Content] at or above the current legal limit of 0.08 g/dL* on weekend nights compared to previous surveys (Figure 1). In 1973, 7.5% of drivers NHTSA’s National Center for Statistics and Analysis had BACs at or above 0.08 g/dL. In 2007, there were only 2.2% of drivers with a BAC at or above the current legal limit. This represents a decline of 71% in the percentage of alcohol-impaired drivers on the road on weekend nights. Similar declines were found at other BAC levels. For example, the percentage of drinking drivers (any positive BAC) declined almost as much over this time period, but one cannot infer impairment at very low BACs."

Compton, Richard and Berning, Amy, "Results of the 2007 National Roadside Survey of Alcohol and Drug Use by Drivers" (Washington, DC: Dept. of Transportation, National Highway Traffic Safety Administration, July 2009), DOT HS 811 175, p. 1.

22. Odds Ratio of Fatal Motor Vehicle Crash Associated With Various Substances

"The estimated odds ratios of fatal motor vehicle crashes associated with different drugs reported in this population-based case-control analysis are generally consistent with previous studies (Bedard et al., 2007; Brault et al., 2004; Laumon et al., 2005; Mathijssen and Houwing, 2005; Movig et al., 2004; Mura et al., 2003). For instance, in a case-control study conducted in the Netherlands, Movig et al. (2004) found that 11.8% of the drivers who were seriously injured in crashes and 6.0% of the drivers who were not involved in crashes tested positive for marijuana, yielding an odds ratio of 2.1 (95% CI: 1.1, 4.0). A study of drivers aged 18 to 69 years of age in Norway revealed that the incidence of crashes was more than two times higher for individuals the week after benzodiazepine-like hypnotics were dispensed compared to unexposed person time (Gustavsen et al., 2008). A meta-analysis of epidemiological studies showed that motor vehicle crash risk for benzodiazepine users was 60–80% higher than for nonusers (Dassanayake et al., 2011). It is also evident that crash risk in drivers with depression is particularly high at the initiation of antidepressant treatment and when antidepressant treatment regimen changes (Orriols et al., 2012)."

Guohua Li, Joanne E. Brady, and Qixuan Chen. Drug use and fatal motor vehicle crashes: A case-control study. Accident Analysis and Prevention 60 (2013) 205–210. http://dx.doi.org/10.1016/j.aa....

23. Prevalence and Trends in Alcohol Use by Drivers in the US

"The comparison of the BAC [Blood Alcohol Content] test results from the four NRS [National Roadside Survey] studies suggests that, during the most recent decade, there continues to be a downward trend in the proportion of drivers with positive BACs21 on U.S. roads on weekend nights, from 36.1 percent in 1973, 25.9 percent in 1986, 16.9 percent in 1996, to a low of 12.4 percent in 2007. Though the response rates we achieved in the 2007 NRS are somewhat lower than NRS studies conducted in previous decades, they are still well above those obtained with Random Digit-Dialing telephone surveys, which currently are typically lower than 50 percent (Battaglia, Frankel, & Link, 2008). We also obtained PAS [Passive Alcohol Sensor] readings from well over 90 percent of these drivers who did not provide actual breath tests. This allowed us to impute BAC values for nearly every driver eligible for an interview. Since the 1996 NRS, the proportion of drivers with BACs .08 g/dL or above on the road has declined substantially from 4.3 percent in 1996 to 2.2 percent in 2007.
"Across the four NRS surveys (1973, 1986, 1996, and 2007), reductions in .08 g/dL and above drivers in the NRS have been generally paralleled by reductions in fatal alcohol-related crashes involving drivers with a BAC of .08 or greater. The reduction in nighttime NRS drivers with BAC .08 g/dL or above from 1996 to 2007 appears to be greater than the reduction in FARS [Fatality Analysis Reporting System] from 1996 to 2007. Results from the FARS data analyses show that drivers with a .08 g/dL or higher in fatal crashes changed from 33.1 percent in 1996 to 32 percent in 2007, whereas the percentage of drivers at or above .08 in the 1996 NRS was 4.3 and fell to 2.2 in 2007. This is a departure from the trends observed from past NRS studies in that, from 1973 to 1986 and then from 1986 to 1996, the same pattern of reductions was observed both in fatal crashes and in the NRS."

Lacey, John H., et al. (2009). 2007 National Roadside Survey of Alcohol and Drug Use by Drivers: Alcohol Results. (DOT HS 811 248). Washington, DC: National Highway Traffic Safety Administration, p. 68.

24. Prevalence of Alcohol Use by Drivers in the US, by Gender

"The percentage of male drivers with a BAC over the current legal limit of 0.08 g/dL was 42% higher than the percentage of female drivers with illegal BACs (Figure 2). A regression analysis showed that males were significantly more likely to have illegal BACs (p < .01). Over 2% of the weekend nighttime drivers had illegal BACs (>0.08g/dL) while only 0.1% of daytime drivers had illegal BACs."

Compton, Richard and Berning, Amy, "Results of the 2007 National Roadside Survey of Alcohol and Drug Use by Drivers" (Washington, DC: Dept. of Transportation, National Highway Traffic Safety Administration, July 2009), DOT HS 811 175, p. 1.

25. Prevalence of Substance Use Among Drivers in EU

"Roadside surveys conducted in 13 countries across Europe, in which blood or oral fluid samples from 50 000 drivers were analysed, revealed that alcohol was present in 3.48 %, illicit drugs in 1.90 %, medicines in 1.36 %, combinations of drugs or medicines in 0.39 % and alcohol combined with drugs or medicines in 0.37 %. However, there were large differences among the mean values in the regions of northern, eastern, southern and western Europe. Although the absolute numbers were quite low, the prevalence of alcohol, cocaine, cannabis and combined substance use was higher in southern Europe, and to some extent in western Europe, than in the other two regions, whereas medicinal opioids and ‘z-drugs’, such as zopiclone and zolpidem, were detected more in northern Europe."

European Monitoring Centre for Drugs and Drug Addiction, "Driving Under the Influence of Drugs, Alcohol and Medicines in Europe — findings from the DRUID project" (Luxembourg: Publications Office of the European Union, 2012), doi: 10.2810/74023, p. 6.