Browsing by Author "Soccolich, Susan"
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- A Case Study Approach to Understand Heavy Truck Safety-critical Events in Work ZonesDunn, Naomi; Soccolich, Susan; Hickman, Jeffrey S. (National Surface Transportation Safety Center for Excellence, 2022-08)Large trucks are overrepresented in work zone crashes. Data from the Federal Motor Carrier Safety Administration’s Large Truck and Bus Crash Facts show that, in 2017, 30% of work zone fatal crashes and 12% of work zone injury crashes involved at least one large truck, which was more than double the percentage of all crashes that occurred outside of work zones, where 12% of fatal crashes and 5% of injury crashes involved at least one truck. This study used data from four major truck naturalistic driving studies to investigate the risk associated with a variety of work zone roadway, environmental, and safety features. The vast majority of the work zone observations occurred with no adverse weather conditions present, dry road conditions, straight roadway alignment, and light traffic, with roughly three-quarters of commercial motor vehicle (CMV) drivers wearing a seatbelt. The most common features observed in work zones were warning signs, barrel barriers, and lane closures, which were used in various combinations. Traffic cones were associated with an increase of safety-critical event (SCE) risk, likely as a result of their small size and being less visible to CMV drivers. Reflective signs, barrels, and concrete barriers, however, reduced the SCE risk for CMV drivers in work zones by 40%–60%. There was a small decrease in SCE risk associated with light traffic in a work zone compared to moderate and heavy traffic. There was also a nearly 3-times greater risk of a CMV driver being involved in an SCE in work zones on single-lane roadways versus four-lane roadways. Active work zones had nearly twice the SCE risk for CMV drivers compared to inactive work zones. In active work zones, non-driving-related distractions, internal distractions, and external distractions all resulted in an almost three-fold increase in SCE risk for CMV drivers. When planning smaller, more temporary work zones, it may be beneficial for worker and road user safety if planners employ larger, more visible safety barriers such as barrels and reflective signage.
- Challenges in Conducting Empirical Epidemiological Research with Truck and Bus Drivers in Diverse Settings in North AmericaSoccolich, Susan; Ridgeway, Christie; Mabry, J. Erin; Camden, Matthew C.; Miller, Andrew; Iridiastadi, Hardianto; Hanowski, Richard J. (MDPI, 2022-09-30)Over 6.5 million commercial vehicle drivers were operating a large truck or bus in the United States in 2020. This career often has high stress and long working hours, with few opportunities for physical activity. Previous research has linked these factors to adverse health conditions. Adverse health conditions affect not only the professional drivers’ wellbeing but potentially also commercial motor vehicle (CMV) operators’ safe driving ability and public safety for others sharing the roadway. The prevalence of health conditions with high impact on roadway safety in North American CMV drivers necessitates empirical epidemiological research to better understand and improve driver health. The paper presents four challenges in conducting epidemiological research with truck and bus drivers in North America and potential resolutions identified in past and current research. These challenges include (1) the correlation between driving performance, driving experience, and driver demographic factors; (2) the impact of medical treatment status on the relationship between health conditions and driver risk; (3) capturing accurate data in self-report data collection methods; and (4) reaching the CMV population for research. These challenges are common and influential in epidemiological research of this population, as drivers face severe health issues, health-related federal regulations, and the impact of vehicle operation on the safety of themselves and others using the roadways.
- Investigating Attributes of Young, Inexperienced Commercial Motor Vehicle DriversSoccolich, Susan; Camden, Matthew C.; Hanowski, Richard J. (National Surface Transportation Safety Center for Excellence, 2024-04-19)For years, the trucking industry has been concerned with a potential lack of qualified, safe drivers to meet the future demand of the supply chain. The current minimum age at which a driver with a commercial driver’s license (CDL) can operate interstate is 21 years old (49 CFR 391.11). However, recent developments have expanded driver licensing age requirements through the Federal Motor Carrier Safety Administration’s young driver apprenticeship programs and initiatives for young military veterans. The current study used the Commercial Driver Safety Risk Factors (CDSRF) study data to investigate the attributes of safe and unsafe young, inexperienced drivers (ages 21 to 25). The study compared young commercial drivers with and without carrier-recorded crashes, carrier-recorded preventable crashes, nationally recorded crashes, and moving violations for differences in demographic characteristics, driving-related factors, and health-related variables such as medical conditions and treatment status. Overall, most young drivers in the current study did not have a safety-related event. The proportion of drivers with a safety-related event included 14% with at least one carrier-recorded crash, 8% with at least one carrier-recorded preventable crash, 8% with at least one nationally recorded crash, and 10% with at least one moving violation. The study found young drivers who reported an out-of-service (OOS) placement in the past 3 years were at 3 times increased risk of nationally recorded crash involvement. Young drivers with a double/triple trailer endorsement had higher odds of both carrier-recorded and nationally recorded crash involvement compared to drivers without this endorsement. Approximately 80% of the sampled young drivers in the current study had a high school (HS) diploma or higher degree—a higher proportion than observed in an analysis of drivers of all ages in the CDSRF. Drivers showed lower odds of carrier-recorded crash involvement when their academic degree was another degree not listed compared to drivers with a HS diploma or bachelor’s degree. Finally, drivers with diagnosed and treated allergies showed higher risk of crash involvement compared to drivers without this diagnosis; however, it is important to note that very few drivers in the sample had allergies and were receiving treatment. Although the study found few statistically significant factors associated with increased safety event risk, the study did provide more insight into the typical young driver. As younger drivers have more opportunities to join the career field, it is important to better understand this driver age group, their potential risk factors, what factors need further research, and how this driver age group compares to other driver age groups in their demographics and risk.
- Safety Benefits of a Carrier-implemented Sleep Apnea Program for Commercial Motor Vehicle DriversMabry, J. Erin; Glenn, T. Laurel; Soccolich, Susan; Hickman, Jeffrey S.; Durmer, Jeffrey (National Surface Transportation Safety Center for Excellence, 2022-10-11)The Virginia Tech Transportation Institute (VTTI) collaborated with a leading third-party population sleep health provider, Fusion Health, and two for-hire carriers to perform an independent analysis of the safety benefits of two, carrier-implemented obstructive sleep apnea (OSA) programs for commercial motor vehicle (CMV) drivers (OSAFE). The research team obtained OSA diagnostic and treatment data from Fusion Health and safety and driver information from the participating carriers. The crash types assessed in the analysis included claims-only, on-road, and preventable crashes. To compare OSA-treated drivers to drivers without diagnosed OSA, a matched cohort approach was taken to include treated drivers and drivers without diagnosed OSA. Safety performance was investigated to explore crash rates before and during PAP treatment, crash rates by treatment adherence and average usage, and crash rates before and during treatment for drivers with a previous crash. The main findings from this study include the following: (1) high PAP adherence rates among OSA drivers, with more than 90% of drivers from both carriers meeting full-adherence requirements for PAP compliance; (2) support for the safety benefits of PAP treatment in CMV drivers who were OSA positive and demonstrated full adherence to treatment; (3) pronounced safety benefits for CMV drivers that experienced a crash prior to beginning PAP treatment; (4) a dose-response safety benefit of PAP use among drivers at Carrier A; and (5) for Carrier A drivers with full adherence to PAP, higher rates of claims-only and preventable crashes before and during treatment compared to similar control drivers. Given that fully compliant PAP treatment was associated with reductions in on-road and preventable crashes, carriers should focus on (1) identifying OSA drivers through effective screening programs, (2) providing PAP treatment, (3) monitoring PAP compliance, and (4) providing support to assist drivers in maintaining OSA compliance.
- Streamlining Drowsiness Assessment: An In-Depth Review of ORD and PERCLOS MethodsSoccolich, Susan; Hammond, Rebecca; Camden, Matt; Walker, Stuart (National Surface Transportation Safety Center for Excellence, 2024-03-15)Every year, drowsy and fatigued driving contributes to thousands of crashes and their resulting injuries and fatalities. Naturalistic driving data allows researchers an opportunity to better understand drowsy driving through review of driver-facing video capturing the driver’s behavior and eyes. Two drowsiness measures that have been successfully used in naturalistic driving data are Observer Rating of Drowsiness (ORD) (Wiegand, McClafferty, McDonald, & Hanowski, 2009) and manual percentage of eye closure (PERCLOS) (Wierwille & Ellsworth, 1994). The current study explored how different drowsiness measures impact fatigue determination for an event and study estimates of fatigue prevalence, risk, and secondary task association for truck and motorcoach drivers. Analyses investigated PERCLOS scores using 1 minute of data (PERCLOS 1) versus 3 minutes of data (PERCLOS 3). The study found the sample size of events with PERCLOS data increased by 8.94% when PERCLOS 1 criteria were used. Overall, matching fatigue determination (whether fatigue was observed) in PERCLOS 3 and PERCLOS 1 scores was found for between 95.89% and 99.48% of truck and motorcoach baselines (BLs) and safety-critical events (SCEs). The risk of SCE involvement when driving while fatigued was consistent for truck drivers when using PERCLOS 1 or PERCLOS 3 to determine fatigue. However, for motorcoach drivers, the risk of SCE involvement when driving while fatigued depended on the PERCLOS measure used. The study also aimed to determine how to potentially lessen the effort of fatigue data reduction in future studies and obtain the most valuable dataset at the lowest cost to time and budget. The single fatigue reduction approach with the lowest time and cost budget was PERCLOS 1 for all events. However, a targeted fatigue reduction approach that includes ORD for all events and targeted PERCLOS 3 or PERCLOS 1 reduction for events that meet or exceed an ORD threshold can reduce the cost of fatigue reduction while maintaining the advantage of ORD reduction.
- Unravelling the Complexity of Irregular Shiftwork, Fatigue and Sleep Health for Commercial Drivers and the Associated Implications for Roadway SafetyMabry, J. Erin; Camden, Matthew; Miller, Andrew; Sarkar, Abhijit; Manke, Aditi; Ridgeway, Christiana; Iridiastadi, Hardianto; Crowder, Tarah; Islam, Mouyid; Soccolich, Susan; Hanowski, Richard J. (MDPI, 2022-11-10)Fatigue can be a significant problem for commercial motor vehicle (CMV) drivers. The lifestyle of a long-haul CMV driver may include long and irregular work hours, inconsistent sleep schedules, poor eating and exercise habits, and mental and physical stress, all contributors to fatigue. Shiftwork is associated with lacking, restricted, and poor-quality sleep and variations in circadian rhythms, all shown to negatively affect driving performance through impaired in judgment and coordination, longer reaction times, and cognitive impairment. Overweight and obesity may be as high as 90% in CMV drivers, and are associated with prevalent comorbidities, including obstructive sleep apnea, hypertension, and cardiovascular and metabolic disorders. As cognitive and motor processing declines with fatigue, driver performance decreases, and the risk of errors, near crashes, and crashes increases. Tools and assessments to determine and quantify the nature, severity, and impact of fatigue and sleep disorders across a variety of environments and populations have been developed and should be critically examined before being employed with CMV drivers. Strategies to mitigate fatigue in CMV operations include addressing the numerous personal, health, and work factors contributing to fatigue and sleepiness. Further research is needed across these areas to better understand implications for roadway safety.