Areas of Expertise

Effects of Alcohol & Drugs

The excessive use of alcohol (and other drugs) has been implicated as a significant causal factor in accidents of all kinds. The Dunlap team has conducted significant landmark research on the effects of alcohol, evaluated devices for measuring alcohol levels, and assessed performance decreases. We are in the process of conducting some of the largest studies of how alcohol and other drugs impact human behavior in the transportation system. We can provide data-driven expertise as to how alcohol and drugs impact individuals in a variety of circumstances and domains.

Ongoing Projects

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National Roadside Study of Alcohol and Other Drug Prevalence

A study that seeks to create national estimates of alcohol and other drug prevalence among drivers in the United States. The study will collect breath and oral fluid specimens from 8,000 drivers at 300 roadside locations across the country. The study will also gather specimens from a convenience sample of other road users (e.g., pedestrians, bicyclists).

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Determining Feasibility of Alternative Standardized Field Sobriety Tests

A study investigating whether certain tasks may serve as feasible alternatives to the current Standardized Field Sobriety Tests (SFSTs) when detecting alcohol consumption among drivers. The project is designed to determine whether there are feasible options to determine likely alcohol consumption in cases where the current SFSTs are less suitable (e.g., unsafe roadway conditions, testing individuals with mobility difficulties, etc.). Specifically, this study is designed to identify tests which are suitable for evaluating sobriety in a law enforcement context while not including an evaluation of eye movements or requiring suspect drivers to walk or stand as part of the assessment. Key components of this study include: (1) a broad examination of candidate tests from many domains of research, including several sectors not traditionally associated with assessments of sobriety (e.g., clinical and/or cognitive assessments); (2) a controlled dosing study to determine the diagnostic accuracy and deployment feasibility of tests selected as promising SFST alternatives; and (3) an assessment of whether tests that succeed in the dosing study can be meaningfully integrated within the current SFST battery to supplement the utility and/or flexibility of the assessment with respect to variable environmental conditions or physical limitations of drivers.

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Examine the Feasibility of Development of a Sentinel Surveillance System for Impaired Driving

A project to determine the feasibility of a sentinel surveillance system (SSS) for drug use among drivers and other road users using trauma centers or other facilities. This project involves preparing a “How To Guide” detailing steps, requirements, resource needs, coordination requirements, and potential issues and solutions to these issues. The research team intends to work with subject matter experts and other cooperating organizations (e.g., trauma centers, toxicology labs) to examine how other systems have been developed and are maintained, assess needs, and understand shortcomings of current systems. 

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Updated Impaired Driving Task Force Guide

A project that aims to update the 2009 Impaired Driving Task Force Guide to assist States in reducing impaired driving. This project will build on the older version of the Guide to provide State and local leaders with practical tools and strategies for establishing or enhancing impaired driving task forces. The information for the updated Guide will be gathered through discussions with State and community leaders in States with successful task forces.

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Development and Testing of Cannabis-Impaired Driving Detection Cues

A study that involves the development and testing of a set of cues to detect individuals driving under the influence of cannabis. The study involves an extensive literature review, analysis of crash and arrest reports, interviews with drug recognition experts, and ride alongs with officers on DUI patrol to identify potential cues for further study. Once potential cues have been identified, the study includes a validation effort to determine whether the cues in fact are predictive of cannabis-impaired driving in a field test.

Past Projects

  • A study of how Utah’s move to a .05% BAC per se law for alcohol impaired driving impacted safety in the State. The study included a comprehensive evaluation of crashes, injuries, citations, arrests, alcohol sales, and a variety of other measures of interest.

  • A project that created a start-to-finish how-to guide for any State wishing to conduct a statewide survey of alcohol and other drug prevalence among drivers. The guide included information on how to develop a study plan, budget, and conduct specimen collection. It also contained information on the research questions that can be addressed, personnel and equipment needed, and issues that may arise (e.g., how to handle an impaired driver).

  • A study on the prevalence of alcohol and other drugs among road users involved in fatal and serious injury crashes. The study gathered blood samples from over 7,500 seriously injured drivers and other road users treated at seven trauma centers, or victims dead at the scene transported directly to the morgue at those locations. The study also coordinated with the National Institutes of Health to study the prevalence of SARS-CoV-2 antibodies in the systems of the study participants to better understand the spread of the virus.

  • A study that looked at the effect of impaired driving laws in different US states according to whether the State made a distinction between drug-impaired and alcohol-impaired driving. The intent was to investigate differences between the enforcement, prosecution, and record keeping associated with States that did or did not make a distinction between drug-impaired and alcohol-impaired driving. Data that was gathered included citations, crashes, and fatalities specifically in the States of California, Massachusetts, and Maryland. This study investigated how the entire process from traffic stop through sanction was affected by legislation in these states.

  • A study that documented the relationship between type of impaired driving law and law enforcement, prosecutorial, judicial, and recordkeeping practices.

  • A project that examined whether fatally injured pedestrians with high BACs had prior DWIs as motor vehicle drivers which led to a license suspension/revocation. Data from a number of States were explored to determine if alcohol positive/negative pedestrians and drivers with high BACs have different driving records.

  • A project that that assessed the BAC of older drivers admitted to a Level 1 Trauma Center relative to drivers of other ages and people admitted to the hospital for non-driving related reasons. The study included a responsibility analysis that showed older drivers at high BACs are almost always responsible for a crash.

  • This study developed and implemented a high visibility enforcement campaign over two motorcycle riding seasons to prevent impaired riding. A law enforcement agency was recruited to implement the campaign and media strategies were developed that focused on social media and the Internet. Extensive coding of the social media data was performed in addition to the enforcement.