Investigating Critical Incidents, Driver Restart Period, Sleep Quantity, and Crash Countermeasures in Commercial Vehicle Operations Using Naturalistic Data Collection

Blanco, Myra; Hickman, Jeffrey S.; Olson, Rebecca L; Bocanegra, Joseph L; Greening, Mike; Madison, Phillip; Holbrook, G. Thomas; Hanowski, Richard J.; Nakata, Akiko; Bowman, Darrell S. · 2016 · ROSA P / United States. Department of Transportation. Federal Motor Carrier Safety Administration

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Summary

This report presents the final results of the Naturalistic Truck Driving Study (NTDS), an on-road naturalistic driving study commissioned by the Federal Motor Carrier Safety Administration (FMCSA). The research aimed to investigate light-vehicle/heavy-vehicle (LV-HV) interactions and other safety issues related to commercial motor vehicle (CMV) crash risk. The primary objective was to document crashes, near-crashes, and crash-relevant conflicts from the heavy-vehicle driver’s perspective to identify functional countermeasures. These findings are intended to support the development of effective technologies, enforcement strategies, and training programs to reduce CMV crashes, injuries, and fatalities. The study focused on three main areas: work/rest parameters relating to driver fatigue, event causation, and applicable countermeasures. The study employed a naturalistic data collection method during normal revenue-producing operations without experimental manipulations. Researchers recruited 100 participants holding Class-A commercial driver’s licenses from four different trucking fleets, instrumenting nine trucks in total. Each participant was observed for approximately four consecutive weeks. Data collection utilized a comprehensive Data Acquisition System (DAS) comprising sensors, vehicle networks, incident boxes, and five video cameras. Additionally, drivers wore actigraphy devices to monitor sleep quantity and completed daily activity registers to record work/rest schedules and medication use. The study collected over 14,500 hours of valid driving data, covering nearly 735,000 miles, along with more than 65,000 hours of actigraphy data and 26,000 hours of on-duty activity records. Analysts identified and validated 2,899 safety-critical events (SCEs), including 13 crashes, 61 near-crashes, 1,594 crash-relevant conflicts, 1,215 unintentional lane deviations, and 16 illegal maneuvers. The analysis addressed specific research questions regarding the relationship between driver fatigue metrics and SCEs. The study examined the impact of the FMCSA restart period and sleep patterns on incident involvement. Researchers analyzed variables such as the duration of the restart period, time since the last restart, and sleep quantity in the 24 hours preceding an event. The results detailed the frequency and characteristics of SCEs as a function of these fatigue-related variables. Furthermore, the study analyzed LV-HV interactions, categorizing events by vehicle type, position, and pre-event movements to determine causation and fault. The data provided specific distributions of driver behaviors, environmental conditions, and roadway factors associated with critical incidents. The significance of this study lies in its contribution to understanding the functional countermeasures needed to mitigate CMV crash risks. By linking naturalistic driving data with physiological sleep data and regulatory work/rest parameters, the report provides evidence-based insights into how fatigue and restart periods influence safety-critical events. The identification of specific crash causation factors and LV-HV interaction patterns offers a foundation for developing targeted interventions. These findings are expected to assist policymakers and industry stakeholders in refining hours-of-service regulations, improving driver training, and designing advanced safety technologies to enhance commercial vehicle operations.

Key finding

The study identified 2,899 safety-critical events, comprising 13 crashes, 61 near-crashes, 1,594 crash-relevant conflicts, 1,215 unintentional lane deviations, and 16 illegal maneuvers, which were analyzed against work/rest and sleep data.

Methodology

naturalistic

Sample size: 97

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