This study included the collection of data from observations (e.g., estimated age and race/ethnicity), self-report and biological measures. Self-report portions were funded by the National Institute of Drug Abuse (NIDA) and the Insurance Institute for Highway Safety (IIHS).

An objective was to obtain at least 7,500 oral fluid samples for analysis. Oral fluid and blood samples were subjected to laboratory screening and liquid chromatography-mass spectrometry (LC/MS/MS; the term MS/MS is the combination of two mass analyzers in one mass spec instrument) and gas chromatography-mass spectrometry (GC/MS) confirmation respectively for alcohol and six classes of drugs, allowing researchers to estimate a national prevalence of alcohol and other drugs in drivers. This report describes the field methods used to conduct this study, including data collection procedures.

Data from this study is available in four formats: SAS, SPSS, Stata, and Excel; the data dictionary is compatible for all four file formats.

• SAS database
• SPSS database
• Stata database
• Excel database
• Data dictionary

A weighting variable is provided for application. Its construction is described in the methodology report.