Measuring Drug Use Among Drivers: How Accurate Is Self-Reported Use?

Area of Science:

• Drug use and toxicology
• Road safety and public health
• Survey methodology

Background:

• Validating self-reported drug use with bioassays is crucial but understudied in roadside settings.
• Understanding drug use among drivers is vital for public health and safety initiatives.

Purpose of the Study:

• To assess the validity of self-reported drug use among U.S. drivers using roadside bioassays.
• To examine trends in the accuracy of self-reported drug use over time.

Main Methods:

• Analysis of nationally representative roadside survey data from 2007 and 2013-2014.
• Comparison of self-reported drug use (past 24 hours) with bioassay results (oral fluid/blood) for cannabis, opioids, cocaine, antidepressants, and benzodiazepines.
• Utilized phi coefficients and logistic regression to assess validity and influencing factors.

Main Results:

• Overall validity (phi coefficients) improved from 2007 (.17–.34) to 2013-2014 (.30–.54).
• Significantly higher odds of reporting for cannabis, cocaine, and benzodiazepines in 2013-2014 compared to 2007.
• No significant change in reporting accuracy for opioids and antidepressants between survey years.

Conclusions:

• Roadside surveys are essential for monitoring drug use trends in drivers.
• Accurate measurement of drug use in drivers is complex due to self-reporting factors and biological limitations.
• Further research is needed to enhance drug use measurement techniques in this population.