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DTNH22-11-D-00226-0004, 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. 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 THCpositive 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.

DTNH22-11-D-00226-0004, 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. 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.

DTNH22-11-C-00216L, This report describes the alcohol results from the 2013–2014 National Roadside Survey (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. This study involved a random sample of drivers at 300 locations across the continental United States. The sites were selected through a stratified random sampling procedure. Data was collected during one 2-hour Friday daytime session (either 9:30 to 11:30 a.m. or 1:30 to 3:30 p.m.) at 60 locations and during four 2-hour nighttime periods (10 p.m. to midnight and 1 to 3 a.m. on both Friday and Saturday nights) at 240 locations. Data included observational and biological samples. Biological samples included breath-alcohol measurements from 9,455 respondents, oral fluid samples from 7,881 respondents, and blood samples from 4,686 respondents. This report focuses on the alcohol breath-test results, presents the 2013-2014 prevalence estimates for alcohol-involved driving, and compares them with the four previous NRS studies. The data indicates a continuing trend of decreasing alcohol-involved driving on U.S. roads during weekend nights over the five NRS studies, including a large change in the percentage of drivers who were alcohol positive, from 36.1% in 1973 to 8.3% in 2013-2014, and an 80% reduction in the percentage of drivers with breath alcohol concentrations (BrACs) of .08 grams per deciliter (g/dL) and higher, from 7.5% in 1973 to 1.5% in 2013-2014.

DTNH22-06-C-00040, This report presents the prevalence estimates for alcohol-involved driving derived from the recently completed U.S. national field survey of alcohol- and drug-involved driving (primarily of nighttime weekend drivers, but also daytime Friday drivers) and compares those estimates with the three previous National Roadside Surveys. This survey involved randomly stopping drivers at 300 locations across the 48 contiguous United States. Data were collected during 2-hour Friday daytime sessions (9:30 a.m. to 11:30 a.m. or 1:30 p.m. to 3:30 p.m.) at 60 locations and during four 2-hour nighttime periods (10 p.m. to midnight and 1 a.m. to 3 a.m. on Fridays and Saturdays) at 240 locations. Both self-report and biological measures were taken. Biological measures included breath-alcohol measurements on 9,413 respondents, oral fluid samples from 7,719 respondents, and blood samples from 3,276 respondents. A prior report described the sampling plan and data collection methodology and summarized the response patterns to the various stages of the multipart survey. A third report, based on analyses of the oral fluid and blood specimens collected, will present the first national prevalence estimate of drug-involved driving and of alcohol-plus-drug-involved driving. This report focuses on the alcohol breath-test results and how they relate to previous national surveys. It also summarizes response patterns to survey questions and to an alcohol-use-disorder-screening instrument. The data indicate a continuing trend over the past three decades of fewer alcohol-involved drivers on the Nation’s roads during weekend nights.

RP209, The Center for Health and Safety Culture conducted research for the Idaho Transportation Department to develop media messages and tools to reduce fatalities and serious injuries related to Run-Off-the-Road, single-vehicle crashes in Idaho using the Positive Community Norms framework. After a review of Idaho’s Crash Database and a sample of police reports, the research team proposed to focus on impaired driving, a major risk factor for these crashes, by increasing bystander engagement. The theory of planned behavior was the theoretical basis for a survey of Idaho adults implemented by the University of Idaho’s Social Science Research Unit. The survey results informed key media messages to increase the likelihood adults would engage in preventing others from impaired driving. Recommendations for communications, implementation and evaluation are provided.

RP209, The Center for Health and Safety Culture conducted research for the Idaho Transportation Department to develop media messages and tools to reduce fatalities and serious injuries related to Run-Off-the-Road, single-vehicle crashes in Idaho using the Positive Community Norms framework. After a review of Idaho’s Crash Database and a sample of police reports, the research team proposed to focus on impaired driving, a major risk factor for these crashes, by increasing bystander engagement. The theory of planned behavior was the theoretical basis for a survey of Idaho adults implemented by the University of Idaho’s Social Science Research Unit. The survey results informed key media messages to increase the likelihood adults would engage in preventing others from impaired driving. Recommendations for communications, implementation and evaluation are provided.

DTNH22-11-C-00216, 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. This study involved randomly stopping drivers at 300 locations across the continental United States. The locations were selected through a stratified random sampling procedure. Researchers collected the data during a 2-hour Friday daytime session (either 9:30 a.m. to 11:30 a.m. or 1:30 p.m. to 3:30 p.m.) at 60 locations and during four 2-hour nighttime periods (10 p.m. to midnight and 1 a.m. to 3 a.m. on Friday and Saturday nights) at 240 locations, for a total of 300 locations. Data included both 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. The report also details overall response rates. Two additional reports will present the results of the data collection and analyses. One will focus on alcohol-use prevalence estimates among drivers and compare them with previous NRS results from studies conducted in 1973, 1986, 1996, and 2007. The other will provide drug-use prevalence estimates among drivers, including comparison to the 2007 numbers. This will then present the first trend data on on-road drug-po

DTNH22-11-C-00216L, 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 2024-01-19. Please email NTLDataCurator@dot.gov if you have questions or issues opening files. NTL staff will provide what assistance they can., This dataset supports the conclusions of the 2013–2014 National Roadside Study of Alcohol and Drug Use by Drivers. The three report volumes -- Methodology, Drug Results, and Alcohol Results -- are available in this repository and linked to this record., This dataset records results from 11322 roadside surveys conducted across the United States in 2013 and 2014, as described in the Methodology volume. When possible, oral fluid and blood samples were taken and 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. The dataset also includes information from a self-administered questionnaire, also described in the Methodology document. All drivers’ responses were completely voluntary and anonymous. Re-identification risk of study participants from this dataset is very low., The data files are collected into a single ZIP file, with a total size of 54 MB. Included data files: NHTSA_BSR_NRS_2013_2014_Combined_csv_161025_20240116_0730.csv, 47 MB, can be opened with any text editor; NHTSA_BSR_NRS_2013_2014_combined_xlsx_161025_20240116_0730.xlsx, 43 MB, can be opened with Excel or other spreadsheet program; NHTSA_BSR_NRS_2013_2014_combined_sav_161025_20240116_0730.zip, 4 MB, can be viewed with IBM SPSS statistical software; NHTSA_BSR_NRS_2013_2014_combined_sas_161025_20240116_0730.zip, 5 MB, can be viewed with SAS statistical software; and NHTSA_BSR_NRS_2013_2014_combined_dta_161025_20240116_0730.zip, 7 MB, can be viewed with Stata statistical software. Other files include a Data Diction, a DMP, a README.txt, and the related Methodology and Results reports.