DOI: 10.21949/1529969
title: Marijuana, Other Drugs, and Alcohol Use by Drivers in Washington State [Supporting Datasets]

description: National Transportation Library (NTL) Curation Note: This dataset was submitted from an USDOT modal research office, in accordance with U.S. DOT’s Public Access Plan (https://doi.org/10.21949/1503647) Section 7.4.2 Data. While this dataset was created prior to the implementation of the DOT Public Access Plan in 2016, the publishing office is committed to sharing its research data with the public. NTL staff has performed Level C Curation, or Enhanced Curation, on this dataset. This means that NTL staff has: converted data into to new preservation-friendly, open file formats; enhanced documentation and metadata to make the dataset more FAIR; and, checked for the presence of Personally Identifiable Information (PII) or other sensitive data, in order to protect privacy. NTL staff has NOT made any changes to individual data values. NTL staff last accessed this dataset on 2024-01-20. Please email NTLDataCurator@dot.gov if you have questions or issues opening files. NTL staff will provide what assistance they can.
description: This dataset supports the conclusions of the report "Marijuana, Other Drugs, and Alcohol Use by Drivers in Washington State", and its various outputs. In Washington State legal sales 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 1 year after implementation (between June 10, 2014 through June 23, 2015). Of the almost 2,400 participants who provided an oral fluid or blood sample, 14.6 percent of drivers, 19.4 percent of drivers, and 21.4 percent of drivers were THC-positive in Waves 1, 2, and 3, respectively. There were no statistically significant differences between waves. There was a statistically significant increase in daytime prevalence of THC-positive drivers between Wave 1 (7.8%) and Wave 2 (18.4%), and also between Wave 1 and Wave 3 (18.9%). There was an increase in the percentage of THC-positive nighttime drivers with each successive wave, but these increases were not statistically significant. Synthetic marijuana was found in only 2 of the participants.

These data support the results of the following publications available in this repository: Marijuana, Other Drugs, and Alcohol Use by Drivers in Washington State https://doi.org/10.21949/1525795; Marijuana, Other Drugs, and Alcohol Use by Drivers in Washington State: Appendices https://doi.org/10.21949/1525829; Drivers’ Use of Marijuana in Washington State [Traffic Tech] https://doi.org/10.21949/1525833

NTL staff has reviewed the data and feels that re-identification risk of study participants from this dataset is extremely low.

The .ZIP folder of datasets and supporting documentation is 9MB in size. The ZIP contains files in the following formats: .CSV files which can be opened with any text editor; .TXT files which can be opened with any text editor; .PDF files that can be opened with any PDF reader; .DOCX files that can be opened in Microsoft Word and some web-based programs; .SAV files which can be opened with IBM SPSS statistical software; .SAS and .sas7bdat files which can be opened with SAS statistical software; .XLSX files which can be opened with Microsoft Excel and other spreadsheet programs; and, .JSON files which can be opened with text editors or metadata editing programs.