The National Academies

BTSCRP BTS-23 [Active]

Outcomes of Variability in Teen Driving Experience and Exposure: Evidence from the Naturalistic Driving Study

  Project Data
Funds: $400,000
Staff Responsibility: Richard Retting
Research Agency: Virginia Polytechnic Institute and State University
Principal Investigator: Charlie Klauer
Effective Date: 9/12/2022
Completion Date: 9/11/2024
Comments: Research underway


Teen novice drivers are well known to have higher crash rates than other age cohorts. A major safety question that lacks clarity and definitive scientific evidence is whether teen drivers who are exposed to greater diversity of traffic and road environments early in their driving careers have lower crash involvement than those who are exposed to less diversity. Ideally, this question would be addressed by analyzing how driving exposure, both the amount of driving (i.e., exposure) and driving conditions (i.e., road environment and geometry), changes when teens make the transition from supervised to unsupervised driving. Existing data collected for the Second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) offer the opportunity to investigate this research question. While supervised driving data are not available in the SHRP2 NDS, it is possible to compare the diversity of experience in the early months of unsupervised driving with later months. This would allow for empirical examination of the association of exposure to greater diversity with crashes and near-crashes.


The overall objective of this research is to use the SHRP2 NDS data, and other potential naturalistic driving data sources, to evaluate how exposure to driving in more diverse traffic and road environments is associated with teen driver behavior, performance indicators that lead to crashes, and safety surrogate measures (e.g., near-crashes, speeding, observed distracted driving). The analysis should consider changes in driver behavior and subsequent crash risk. Based on the results of the analysis, the study will develop recommendations/strategies for improving teen driver safety.

The period of early exposure during unsupervised driving will be the focus of the proposed research. A research hypothesis will be that teens who spend a greater amount of either time or miles driving in a wider range of environments in their first 6 months of unsupervised driving are significantly less likely to experience a crash or near-crash event in each subsequent 6 months of experience, compared to teens with a more limited/restricted range of experience in their first 6 months of unsupervised driving. If it is found that not enough participants were enrolled in the NDS during their first 6 months of driving experience, this hypothesis may be modified to use the first 12 months of driving experience as the reference interval.


The research plan should delineate the tasks required to accomplish the research objective. At a minimum, the tasks should include the following:
  1. Conduct a state-of-the-art review of performance indicators that are possible to obtain with NDS data; best methodological practices for use of NDS data; and effects of diversity in traffic and road environments on safety outcomes, primarily for teen drivers. Findings from this task shall be summarized in a technical memo.  
  2. Identify appropriate variables that can be used to meet the research objective, an analysis framework, and any limitations associated with obtaining or interpreting the data. As part of this task, determine the ability to quantify/evaluate the level of driver exposure to different traffic and road environments using NDS data.
  3. Identify any additional datasets with the potential to supplement the SHRP2 NDS data, along with their availability, limitations, and how data from multiple sources will be combined in the analysis to support the successful completion of the project.
  4. Conduct an interim panel meeting to present findings from all prior tasks, and to obtain panel approval for the proposed data sources.
  5. Obtain sample data and conduct a preliminary analysis to validate the panel-approved data sources, variables, and analysis approach. Prepare a technical memo that summarizes findings.
  6. If needed, modify data sources and/or analysis approach based on results of the preliminary analysis and provide detailed description of revised approach.
  7. Obtain data and conduct analysis as approved by the panel.
  8. Identify actionable items for state highway safety offices and other stakeholders to improve teen driver safety based on the research findings.
The proposed work plan must be divided into two phases. Each phase must be organized by task, with each task described in detail. A kick-off teleconference of the research team and BTSCRP shall be scheduled within 1 month of the contract’s execution.
Phase I will consist of information gathering and refinement of the research plan for subsequent phases, culminating in the submission of an interim report describing the work completed in Phase I and an updated work plan for accomplishing Phase II. A meeting will be held with BTSCRP to discuss the interim report and review the Phase II work plan. BTSCRP approval of the Phase I interim report is required before work can commence on subsequent phases. The project schedule shall include 1 month for BTSCRP review and approval of the interim report.
Phase II shall consist of the BTSCRP-approved Phase II work plan and the development of the final deliverables.
At a minimum, the final deliverables shall include:
  1. A technical memo that summarizes findings from the state-of-the-art review of performance indicators that are possible to obtain with NDS data; best methodological practices for use of NDS data; and effects of diversity in traffic and road environments on safety outcomes for teen drivers.
  2. An interim report that includes findings from the preliminary analysis and a Phase II work plan.
  3. A final report documenting the entire project and incorporating all other specified deliverable products of the research.
  4. The dataset used for analysis.
  5. A summary of practical, actionable items to improve teen-driver safety based on the research findings. This deliverable shall be a public-facing document prepared for a broad, non-technical audience that desires to use the study findings in an evidence-based pragmatic manner.
  6. A PowerPoint presentation of the findings that also intentionally provide guidance that can be tailored for specific audiences.
  7. A technical memorandum describing the strengths and limitations of the research and recommendations for additional research.
  8. A stand-alone technical memorandum titled “Implementation of Research Findings and Products”.

STATUS: Research underway.

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