VTechWorks
VTechWorks provides global access to Virginia Tech scholarship, including journal articles, books, theses, dissertations, conference papers, slide presentations, technical reports, working papers, administrative documents, videos, images, and more by faculty, students, and staff. Faculty can deposit items to VTechWorks from Elements, including journal articles covered by the University open access policy. Email vtechworks@vt.edu for help.
Open Access Policy
Virginia Tech's open access policy enables researchers to deposit the accepted version of scholarly articles with no embargo.
Theses and Dissertations
Virginia Tech was first in the world to require ETDs in 1997, and continues to add scans of older theses and dissertations.
Open Textbooks
More than 40 freely available and openly licensed textbooks are among our most downloaded items.
Communities in VTechWorks
Select a community to browse its collections.
Recent Submissions
Leadership Strengths Escape Room [2025 Virginia 4-H Congress]
Kaufman, Eric K.; Oyedare, Israel (2025-06-26)
Leadership requires collective problem-solving, leveraging the potential of individuals’ strengths. This workshop will introduce participants to the strengths-based leadership framework and allow them to experience the concepts through an escape room activity. Participants must crack codes and solve puzzles to successfully access a lockbox of prizes. Get ready; the clock is ticking!
Mapping the complex causal mechanisms of drinking and driving behaviors among adolescents and young adults
Hosseinichimeh, Niyousha; MacDonald, Rod; Li, Kaigang; Fell, James C.; Haynie, Denise L.; Simons-Morton, Bruce; Banz, Barbara C.; Camenga, Deepa R.; Iannotti, Ronald J.; Curry, Leslie A.; Dziura, James; Mayes, Linda C.; Andersen, David F.; Vaca, Federico E. (Pergamon-Elsevier, 2022-03)
Background: The proportion of motor vehicle crash fatalities involving alcohol-impaired drivers declined substantially between 1982 and 1997, but progress stopped after 1997. The systemic complexity of alcohol-impaired driving contributes to the persistence of this problem. This study aims to identify and map key feedback mechanisms that affect alcohol-impaired driving among adolescents and young adults in the U.S. Methods: We apply the system dynamics approach to the problem of alcohol-impaired driving and bring a feedback perspective for understanding drivers and inhibitors of the problem. The causal loop diagram (i.e., map of dynamic hypotheses about the structure of the system producing observed behaviors over time) developed in this study is based on the output of two group model building sessions conducted with multidisciplinary subject-matter experts bolstered with extensive literature review. Results: The causal loop diagram depicts diverse influences on youth impaired driving including parents, peers, policies, law enforcement, and the alcohol industry. Embedded in these feedback loops are the physical flow of youth between the categories of abstainers, drinkers who do not drive after drinking, and drinkers who drive after drinking. We identify key inertial factors, discuss how delay and feedback processes affect observed behaviors over time, and suggest strategies to reduce youth impaired driving. Conclusion: This review presents the first causal loop diagram of alcohol-impaired driving among adolescents and it is a vital first step toward quantitative simulation modeling of the problem. Through continued research, this model could provide a powerful tool for understanding the systemic complexity of impaired driving among adolescents, and identifying effective prevention practices and policies to reduce youth impaired driving.
Trajectories and outcomes of adolescents that ride with an impaired driver/drive while impaired
Vaca, Federico E.; Li, Kaigang; Haynie, Denise L.; Gao, Xiang; Camenga, Deepa R.; Dziura, James; Banz, Barbara C.; Curry, Leslie A.; Mayes, Linda; Hosseinichimeh, Niyousha; MacDonald, Rod; Iannotti, Ronald J.; Simons-Morton, Bruce (Elsevier, 2022-03)
Introduction: For young drivers, independent transportation has been noted to offer them opportunities that can be beneficial as they enter early adulthood. However, those that choose to engage in riding with an impaired driver (RWI) and drive while impaired (DWI) over time can face negative consequences reducing such opportunities. This study examined the prospective association of identified longitudinal trajectory classes among adolescents that RWI and DWI with their later health, education, and employment in emerging adulthood. Methods: We analyzed all seven annual assessments (Waves, W1–W7) of the NEXT Generation Health Study, a nationally representative longitudinal study starting with 10th grade (2009–2010 school year). Using all seven waves, trajectory classes were identified by latent class analysis with RWI (last 12 months) and DWI (last 30 days) dichotomized as ≥ once = 1 vs. none = 0. Results: Four RWI trajectories and four DWI trajectories were identified: abstainer, escalator, decliner, and persister. For RWI and DWI trajectories respectively, 45.0% (N = 647) and 76.2% (N = 1657) were abstainers, 15.6% (N = 226) and 14.2% (N = 337) were escalators, 25.0% (N = 352) and 5.4% (N = 99) were decliners, and 14.4% (N = 197) and 3.8% (N = 83) persisters. RWI trajectories were associated with W7 health status (χ2 = 13.20, p <.01) and education attainment (χ2 = 18.37, p <.01). Adolescent RWI abstainers reported better later health status than RWI escalators, decliners, and persisters; and decliners reported less favorable later education attainment than abstainers, escalators, and persisters. DWI trajectories showed no association with health status, education attainment, or employment. Conclusions: Our findings suggest the importance of later health outcomes of adolescent RWI. The mixed findings point to the need for more detailed understanding of contextual and time-dependent trajectory outcomes among adolescents engaging in RWI and DWI.
What determines the success of states in reducing alcohol related crash fatalities? A longitudinal analysis of alcohol related crashes in the US from 1985 to 2019
Hosseinichimeh, Niyousha; Williams, Ross; MacDonald, Rod; Li, Kaigang; Vaca, Federico E. (Pergamon-Elsevier, 2022-09)
In the United States, nearly 28 people die in alcohol–related motor vehicle crashes every day (1 fatality every 52 min). Over decades, states have enacted multiple laws to reduce such fatalities. From 1982 to 2019, the proportion of drivers in fatal crashes with a blood alcohol concentration (BAC) above 0.01 g/dl declined from 41% to 22%. States vary in terms of their success in reducing alcohol–related crash fatalities. The purpose of this study was to examine factors associated with changes in fatalities related to alcohol–impaired driving at the state level. We created a panel dataset of 50 states from 1985 to 2019 by merging different data sources and used fixed–effect linear regression models to analyze the data. Our two outcome variables were the ratio of drivers in fatal crashes with BAC ≥ 0.01 g/dl to those with BAC = 0.00, and the ratio of those with BAC ≥ 0.08 g/dl to those with BAC < 0.08 g/dl. Our independent variables included four laws (0.08 g/dl BAC per se law, administrative license revocation law, minimum legal drinking age law, and zero tolerance law), number of arrests due to impaired driving, alcohol consumption per capita, unemployment rate, and vehicle miles traveled. We found that the 0.08 g/dl per se law was significantly associated with lower alcohol–related crash fatalities while alcohol consumption per capita was significantly and positively associated with crash–related fatalities. Arrests due to driving under the influence (DUI) and crash fatalities were nonlinearly correlated. In addition, interaction of DUI arrests and two laws (0.08 g/dl BAC per se law, and zero tolerance) were significantly associated with lower crash–related fatalities. Our findings suggest that states which have more restrictive laws and enforce them are more likely to significantly reduce alcohol–related crash fatalities.
From text to map: a system dynamics bot for constructing causal loop diagrams
Hosseinichimeh, Niyousha; Majumdar, Aritra; Williams, Ross; Ghaffarzadegan, Navid (Wiley, 2024-07)
We introduce and test the System Dynamics Bot, a computer program leveraging a large language model to automate the creation of causal loop diagrams from textual data. To evaluate its performance, we ensembled two distinct databases. The first dataset includes 20 causal loop diagrams and associated texts sourced from the system dynamics literature. The second dataset comprises responses from 30 participants to a vignette, along with causal loop diagrams coded by three system dynamics modelers. The bot uses textual data and successfully identifies approximately 60% of the links between variables and feedback loops in both datasets. This article outlines our approach, provides examples, and presents evaluation results. We discuss encountered challenges and implemented solutions in developing the System Dynamics Bot. The bot can facilitate extracting mental models from textual data and improve model-building processes. Moreover, the two datasets can serve as a test-bed for similar programs.