VTechWorks staff will be away for the Thanksgiving holiday beginning at noon on Wednesday, November 27, through Friday, November 29. We will resume normal operations on Monday, December 2. Thank you for your patience.

Browsing by Author "Henry, Scott"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Estimating Crash Consequences for Occupantless Automated Vehicles
    Witcher, Christina; Henry, Scott; McClafferty, Julie A.; Custer, Kenneth; Sullivan, Kaye; Sudweeks, Jeremy D.; Perez, Miguel A. (Virgina Tech Transportation Institute, 2021-02)
    Occupantless vehicles (OVs) are a proposed application of automated vehicle technology that would deliver goods from merchants to consumers with neither a driver nor passengers onboard. The purpose of this research was to understand and estimate how the increased presence of OVs in the United States fleet may influence crash risk and associated injuries and fatalities. The approach used to estimate potential modifications in crash risk consequences was a counterfactual simulation, where real-world observations were modified as if alternate events had occurred. This analysis leveraged several U.S. national crash databases, along with the Second Strategic Highway Research Program (SHRP 2) Naturalistic Driving Study (NDS) dataset. The analysis required the derivation of parameters that could be used to modify existing crash estimates as OVs enter the fleet in greater numbers. The team estimated benefit parameters pertaining to (1) the crashes that could be ultimately avoided altogether based on the OV’s smaller size, (2) benefits that could be obtained from the improved crashworthiness characteristics of the OV, and (3) benefits due to the lack of occupants in the OV. Results showed that of the 58,852 fatalities in the national databases examined, a full-scale market penetration of OVs was estimated to reduce fatalities by 34,284, a reduction of 58.2%. Most of this reduction (83%) would come from the lack of occupants in the OVs. Similarly, of the 6,615,117 injured persons in the national databases examined, a full-scale penetration of OVs was estimated to reduce injured persons by 4,088,935, a reduction of 61.8%. As was observed for fatalities, most of this reduction (72.1%) would come from the lack of occupants in the OVs. The results of this investigation, however, should not be taken as definitive benefit estimates. There are important assumptions inherent in the parameters that were used, and some of these assumptions may not be immediately realized. Rather, the results are meant to support critical thinking into how innovative technologies such as OVs may offer benefits that transcend the typical approaches used in vehicle safety, including passive and active safety measures.
  • Thumbnail Image
    Exploration of U.S. National Pedestrian Traffic Crashes
    Witcher, Christina; Henry, Scott; Sullivan, Kaye (National Surface Transportation Safety Center for Excellence, 2022-11-07)
    The number of pedestrian traffic fatalities in the U.S. has been increasing since 2009, following a general decline for several decades, while the number of non-fatally injured pedestrians in traffic crashes remained relatively consistent during the same period. Despite this disparity, there are few traffic safety studies on the differences between fatal and non-fatal injured pedestrians. This exploratory analysis provides a general landscape of the characteristics of recent police-reported crashes for fatally and non-fatally injured pedestrians, including environment, vehicle, driver, and pedestrian characteristics, as well as a comparison of those characteristics for fatal versus non-fatal injured pedestrians. Pedestrian cases were extracted from the U.S. national datasets of police-reported traffic crashes maintained by the National Highway Traffic Safety Administration (NHTSA). Fatal pedestrian crash data were collected from the Fatality Analysis Reporting System for calendar years (CYs) 2010–2019. Non-fatal injured pedestrian crash data were collected from the National Automotive Sampling System General Estimates System for CYs 2010–2015 and the Crash Report Sampling System for CYs 2016–2019. The findings of this landscape analysis can be used to identify potential factors influencing the continued increase in fatalities and the differences between fatal and non-fatal pedestrian crashes. This information is important for determining areas of further study needed to develop or refine vehicle and infrastructure countermeasures and public campaigns to improve pedestrian traffic safety.
  • Thumbnail Image
    Temporal Patterns in U.S. Pedestrian Traffic Crashes
    Witcher, Christina; Henry, Scott; Sullivan, Kaye; Laituri, Tony (2024-04-18)
    The number of pedestrian traffic fatalities in the U.S. has been increasing since 2009, despite a general decline during the preceding decades (Figure ES1). In contrast, changes in the number of non-fatal injured pedestrians in traffic crashes were less pronounced during the same period. Our 2022 pedestrian-centric study, funded by the National Surface Transportation Safety Center for Excellence, focused on the differences between those two populations (i.e., fatal and non-fatal injured pedestrians). This analysis extended that study by exploring fatal and non-fatal injured pedestrians from the perspective of temporal characteristics (e.g., year, month, day of week, hour of day), collected from U.S. national datasets for police-reported traffic crashes maintained by the National Highway Traffic Safety Administration. Fatal pedestrian crash data from the Fatality Analysis Reporting System for the 2010–2019 calendar years were examined. Non-fatal injured pedestrian crash data were weighted estimates from two national data sources: the General Estimates System for calendar years 2010–2015 and the Crash Report Sampling System for calendar years 2016–2019. The findings of this temporal analysis can be used to identify potential factors influencing the continued increase in fatalities and the differences between fatal and non-fatal pedestrian crashes. In addition to providing distributions for each temporal characteristic, the ratio of fatal to non-fatal injured pedestrians in traffic crashes was used to identify “peaks” during which fewer pedestrian-involved crashes occurred and/or the injuries were more severe. This ratio was also used to develop categories that typify weekly driving operations. These measures showed distinct differences for fatal and non-fatal injured pedestrians. Fatal pedestrians occurred more often during early hours, weeknights, and weekend-nights, with peaks at night. Non-fatal injured pedestrians occurred more often during weekdays, evening commutes, and weeknights, with peaks during the day. There were no notable differences observed in the 2020 calendar year temporal patterns for fatal and non-fatal injured pedestrians compared with the period 2017–2019. This information is important for determining areas of further study needed to develop or refine vehicle and infrastructure countermeasures and public campaigns to improve pedestrian traffic safety.