Virginia Tech Transportation Institute (VTTI)

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Browsing Virginia Tech Transportation Institute (VTTI) by Subject "100-car"

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    Contributing Factors to Run-off-road Crashes and Near-crashes
    McLaughlin, Shane B.; Hankey, Jonathan M.; Klauer, Charlie; Dingus, Thomas A. (United States. National Highway Traffic Safety Administration, 2009-01)
    The purpose of this investigation is to identify factors associated with run-off-road (ROR) crashes. Events from the 100-Car Naturalistic Driving Study that constituted ROR crash or near-crash events were investigated to identify conditions in which the events occurred and contributing factors. ROR events occur more frequently per mile in low-visibility (including darkness) and low-friction conditions than in clear and dry conditions. Approximately half of the events (56%) occurred on straight roadways, with the remainder occurring in curves (30%) and intersection turns (14%). The most frequently identified contributing factor among the ROR events was distraction. Changes in roadway boundaries (e.g., discontinuities) also appear to be a common factor. Short following distances appear to be more commonly a factor than lead-vehicle braking. Other factors include fatigue/impairment, low friction, vehicle encroaching on the subject vehicle, low-speed maneuvering errors, and late route selection.
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    The Impact of Driver Inattention on Near-Crash/Crash Risk: An Analysis Using the 100-Car Naturalistic Driving Study Data
    Klauer, Charlie; Dingus, Thomas A.; Neale, Vicki L.; Sudweeks, Jeremy D.; Ramsey, D. J. (United States. National Highway Traffic Safety Administration, 2006-04)
    The purpose of this report was to conduct in-depth analyses of driver inattention using the driving data collected in the 100-Car Naturalistic Driving Study. An additional database of baseline epochs was reduced from the raw data and used in conjunction with the crash and near-crash data identified as part of the original 100-Car Study to account for exposure and establish near-crash/crash risk. The analyses presented in this report are able to establish direct relationships between driving behavior and crash and near-crash involvement. Risk was calculated (odds ratios) using both crash and near-crash data as well as normal baseline driving data for various sources of inattention. The corresponding population attributable risk percentages were also calculated to estimate the percentage of crashes and near-crashes occurring in the population resulting from inattention. Additional analyses involved: driver willingness to engage in distracting tasks or driving while drowsy; analyses with survey and test battery responses; and the impact of driver’s eyes being off of the forward roadway. The results indicated that driving while drowsy results in a four- to six-times higher near-crash/crash risk relative to alert drivers. Drivers engaging in visually and/or manually complex tasks have a three-times higher near-crash/crash risk than drivers who are attentive. There are specific environmental conditions in which engaging in secondary tasks or driving while drowsy is more dangerous, including intersections, wet roadways, and areas of high traffic density. Short, brief glances away from the forward roadway for the purpose of scanning the driving environment are safe and actually decrease near-crash/crash risk. Even in the cases of secondary task engagement, if the task is simple and requires a single short glance the risk is elevated only slightly, if at all. However, glances totaling more than 2 seconds for any purpose increase near-crash/crash risk by at least two times that of normal, baseline driving.
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    Naturalistic Driving Study: Technical Coordination and Quality Control (SHRP 2 Report S2-S06-RW-1)
    Dingus, Thomas A.; Hankey, Jonathan M.; Antin, Jonathan F.; Lee, Suzanne E.; Eichelberger, Lisa; Stulce, Kelly E.; McGraw, Doug; Perez, Miguel A.; Stowe, Loren (Transportation Research Board, 2015)
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    The Risk of a Safety-critical Event Associated with Mobile Device Subtasks in Specific Driving Contexts
    Fitch, Gregory M.; Hanowski, Richard J.; Guo, Feng (National Surface Transportation Safety Center for Excellence, 2014-07-28)
    Using a cell phone while driving has been associated with an increased crash risk. However, when examining the inherent subtasks, naturalistic driving studies (NDSs) have shown that safety-critical event (SCE) risk is associated with visual-manual subtasks – which take the driver’s eyes off the roadway – and not the conversation itself. This study consisted of an analysis of data from NDSs involving commercial motor vehicle (CMV) drivers and light vehicle (LV) drivers. The NDS data sets were partitioned into subsets representative of specific driving contexts. Groupings of (1) level of service, an ordinal measure of traffic density, (2) relation to intersections and merge ramps, and (3) combinations of these two factors were prepared. The data were then “flagged” whenever specific mobile device subtasks were observed. Mobile device usage was investigated by summing all SCEs and baselines for which a subtask was observed in each context and comparing the likelihood of the subtask occurring in each context using chi-squared tests. Odds ratios and their respective 95% confidence intervals were then computed for mobile device subtasks in each context to investigate the association between their presence and the occurrence of an SCE. It was found that CMV and LV drivers varied as to how much they conversed on a mobile device, but did not vary their engagement in visual-manual subtasks, across the driving contexts examined. Furthermore, CMV drivers conversed less frequently when driving task demands were great, and LV drivers did not. The risk of an SCE associated with mobile device use (collapsed across subtasks) was dependent on the driving context as well as each subtask’s associated SCE risk. Only visual-manual subtasks were associated with an increased SCE risk, while conversing was associated with a decreased risk. Overall, the study shows that drivers’ engagement in mobile device subtasks, and the associated SCE risk, varies by driving context. The findings can be used to inform the design of in-vehicle interfaces that mitigate distraction by preventing visual-manual subtasks while driving.