A Data-Driven Framework of Crash Scenario Typology Development for Child Vulnerable Road Users in the U.S.

Motor vehicle crashes involving child Vulnerable Road Users (VRUs) remain a critical public health concern in the United States. While previous studies successfully utilized the crash scenario typology to examine traffic crashes, these studies focus on all types of motor vehicle crashes thus the method might not apply to VRU crashes. Therefore, to better understand the context and causes of child VRU crashes on the U.S. road, this paper proposes a multi-step framework to define crash scenario typology based on the Fatality Analysis Reporting System (FARS) and the Crash Report Sampling System (CRSS). A comprehensive examination of the data elements in FARS and CRSS was first conducted to determine elements that could facilitate crash scenario identification from a systematic perspective. A follow-up context description depicts the typical behavioral, environmental, and vehicular conditions associated with an identified crash scenario. In addition, hypothesis tests are used to reveal over-represented element conditions that separate a specific crash scenario from others. A case study is given on fatal crashes with a single vehicle and a single-child pedestrian to demonstrate the proposed framework. Insights are obtained on the similarities and more interestingly the differences in the context among crash scenarios. For example, compared to crashes noted with “Non-Motorist Contributing Factors” (actions and/or circumstances that may have contributed to the crash) for child pedestrians, crashes without the type of factors noted were associated with a significantly higher proportion of driver violations charged and/or driving under the influence. When involved in a crash, child pedestrians who failed to yield the right-of-way were significantly more likely to be young teens (13-14 years) while those in the roadway improperly were more likely playing toddlers (1-3 years). We expect the work to serve as a fundamental and practical tool for further examination of crash context and causation, especially those involving children, and to improve their safety traveling on the road.