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1 Summary This research was undertaken to assess the potential of mining the vast data resources resulting from the second Strategic Highway Safety Programâs (SHRP2) Naturalistic Driving Study (NDS) to enhance the safety of teen drivers. A research agenda is envisioned where specific strengths of the NDS database are exploited to support the development and evaluation of teen safety countermeasures. This was a Phase 1 project culminating in recommendations for an initial set of teen behavioral analyses that represent the first steps in such an agenda. Naturalistic driving data extends our understanding of (risky) teen driving behavior beyond what can be gleaned from crash analyses, in a number of important ways. It offers the potential to examine behavior on a continuous basis, instead of being limited to an event-based âsnapshotâ; and, critically, it provides an objective record of behavior in contrast to the subjective reports of drivers or after-the-fact inferences about risky behavior that been entered on a police report. Further, naturalistic driving data permits the analysis of (teen driver) behavior in relation to other road users and in the context of a particular set of operating conditions. The SHRP2 NDS includes 553 drivers aged 16-19, whose personal vehicles were instrumented with a data acquisition system that included accelerometers, cameras, GPS, forward radar, and vehicle network connections. This data source contains records of 410 crashes and 1182 near crashes by drivers in this age group. For all such events, and for at least one âbaselineâ trip for each driver where no crash, near crash, crash-relevant, or non-subject conflict event occurred, video coders at the institution serving as data custodian have completed detailed analyses using the in-vehicle camera. This information can provide unparalleled insights regarding behaviors that place teens at elevated crash risk, e.g., distracted driving. A preliminary list of priority research questions was developed based on a recent literature review on teen driving safety and a survey of members of the TRB ANB30 (formerly) Young Driver Subcommittee. The research team examined each question to isolate the terms that would need to be operationalized as independent, dependent, or discriminating variables in teen behavioral analyses, then developed an inventory of variable definitions and data elements drawn from the tables displayed on the SHRP2 InSight website data dictionary and also from the Roadway Information Database (RID). The inventory included the variables necessary to define each measure or measurement construct embedded in the priority research questions, the applicable SHRP2 table and variable, any relevant calculations, and whether the variables can be defined by researchers or must be derived by the SHRP2 data custodian. Through these project activities, the SHRP2 data resource was âmapped ontoâ a set of candidate priorities for the future research agenda, and those that could most feasibly be investigated were identified. A subsequent consideration of supplemental data sources found the most promising to be a post-SHRP2 reduction of NDS video by staff at the data custodian, i.e., the reduction of eye glance location on a frame- by-frame basis to produce a time series of eye glance locations. The glance location data, while very context-reliant, and limited to crash, near crash and baseline events, hold particular appeal for analyses in which driver distraction serves as either an independent or dependent variable. More generally, such data are unrivaled as an allocation-of-attention measure.
2 After identifying the specific data elements best-suited to operationalizing key variables within the high priority research questions, our team narrowed these candidates to those few for which a formal TRB Research Needs Statement would be developed. The graduated driver licensing model guided this selection process. Specifically, our teamâs judgment of the perceived scientific value of analysis outcomes within the GDL framework led to a final prioritization of the following questions. ⢠Does the diversity of traffic/road environments teens are exposed to in their early driving experience predict the probability of crash/near crash involvement, on an exposure basis? ⢠To what extent do driving risks increase (or differ) for vulnerable teen populations, specifically those with an indication of ADHD, apart from the influence of other driver factors? ⢠How and to what extent does driving distraction (internal and external) contribute to teen crashes and near crashes and does that change as teens gain driving experience? The Research Needs Statements (RNSs) elaborating each of these questions are the principal product of this Phase 1 study. Augmenting each RNS is a Data Specification consistent with what is required in a Data Use License application to the data custodian. This identifies every relevant SHRP2 NDS variable and data element, the table from which it will be extracted, and any processing necessary to derive information that cannot be read directly from a table; and if a need to view any Personally Identifying Information (PII) in a secure data enclave is anticipated, this is noted explicitly.
