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Behaviors and Attitudes - NHTSA studies behaviors and attitudes in highway safety, focusing on drivers, passengers, pedestrians, and motorcyclists. We identify and measure behaviors involved in crashes or associated with injuries, and develop and refine countermeasures to deter unsafe behaviors and promote safe alternatives.

Latest Reports  

  • Marijuana, Other Drugs, and Alcohol Use by Drivers in Washington State (DOT HS 812 299)   In Washington State legal sale of marijuana began July 8, 2014. A voluntary, anonymous roadside study was conducted to assess the prevalence of drivers testing positive for alcohol and other drugs including marijuana on Washington’s roads. Data was collected in three waves, before implementation of legal sales, about 6 months after implementation, and one year after implementation. Of almost 2,500 participants, 14.6 percent of drivers, 19.4 percent of drivers, and 21.8 percent of drivers were THC-positive in Waves 1, 2, and 3, respectively. The difference between Waves 1 and 3 was statistically significant (p < .05). There was a statistically significant increase in daytime prevalence of THC-positive drivers between Wave 1 and 2, and also between Wave 1 and 3. The study found that 6.2 percent, 4.1 percent, and 4.6 percent of participants were alcohol-positive across the three waves. There was a significant increase in THC-positive drivers who were alcohol-free at Waves 2 and 3, and a decrease in the percentage of drivers who tested positive for any other drug (besides THC) and were alcohol-free from Wave 1 to Wave 3.
  • Appendices (DOT HS 812 299A)   Appendices for "Marijuana, Other Drugs, and Alcohol Use by Drivers in Washington State" report above (DOT HS 812 299)
  • 2013–2014 National Roadside Study of Alcohol and Drug Use by Drivers - Methodology (DOT HS 812 294)  
    This report describes the methodology for the National Roadside Study (NRS), a national field study to estimate the prevalence of alcohol-, drug-, and alcohol-plus-drug-involved driving primarily among nighttime weekend drivers, but also daytime Friday drivers.
Studies and Reports

U.S. Department of Transportation National Highway Traffic Safety Administration
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