Analysis and detection of driver fatigue caused by sleep deprivation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.Includes bibliographical references (leaves 167-181).Human errors in attention and vigilance are among the most common causes of transportation accidents. Thus, effective countermeasures are crucial for enhancing road safety. By pursuing a practical and reliable design of an Active Safety system which aims to predict and avoid road accidents, we identify the characteristics of drowsy driving and devise a systematic way to infer the state of driver alertness based on driver-vehicle data. Although sleep and fatigue are major causes of impaired driving, neither effective regulations nor acceptable countermeasures are available yet. The first part of this thesis analyzes driver-vehicle systems with discrete sleep-deprivation levels, and reveals differences in the performance characteristics of drivers. Inspired by the human sleep-wake cycle mechanism and attributes of driver-vehicle systems, we design and perform human-in-the-loop experiments in a test bed built with STISIM Drive, an interactive fixed-based driving simulator. In the simulated driving, participants were given various driving tasks and secondary tasks for both non and partially sleep-deprived conditions. This experiment demonstrates that sleep deprivation has a greater effect on rule-based tasks than on skill-based tasks; when drivers are sleep-deprived, their performance of responding to unexpected disturbances degrades while they are robust enough to continue such routine driving tasks as straight lane tracking, following a lead vehicle, lane changes, etc. In the second part of the thesis we present both qualitative and quantitative guidelines for designing drowsy driver detection systems in a probabilistic framework based on the Bayesian network paradigm and experimental data.(cont.) We consider two major causes of sleep, i.e., sleep debt and circadian rhythm, in the framework with various driver-vehicle parameters, and also address temporal aspects of drowsiness and individual differences of subjects. The thesis concludes that detection of drowsy driving based on driver-vehicle data is a feasible but difficult problem which has diverse issues to be addressed; the ultimate challenge lies in the human operator.by Ji Hyun Yang.Ph.D

Determining Contributing Factors for Passenger Airline Pilot Perceived Fatigue

Fatigue is a recurring concern for pilots and continues to be a common contributing cause of aircraft accidents. The purpose of the dissertation was to determine factors that influence fatigue in commercial airline pilots. The ability to accurately associate fatigue in pilots before a flight begins could have a profound and meaningful impact on aviation safety. Seven factors were identified in the literature review as having possible predictive capabilities of perceived fatigue in pilots working for passenger carriers, including time awake, perceived stress, sleep quality, hours of sleep, age, typically scheduled start time, and hours on duty. An electronic survey instrument was used to gather quantitative data from U.S. passenger-carrying airline pilots. Data collected from 271 responses were randomly assigned to two separate groups. First, a regression equation was created utilizing half of the data collected from a survey instrument. The regression identified that age, hours on duty, and sleep quality (JSS) were significant independent variables (IVs) contributing to fatigue. Next, the regression equation was used to create predicted values of perceived fatigue. Then the second half of the dataset was used to validate if the equation could be utilized to identify contributing factors for passenger airline pilots\u27 perceived fatigue. Data were created with the regression equation and compared to perceived fatigue. The model was a moderate fit for the second data set. The analysis identified age as a negative predictor, indicating that fatigue (FSS) decreases as age increases. Age also had the smallest effect size of the significant IVs. These two items, while counterintuitive, are possibly explained by variances in schedules between pilot seniority. Sleep Quality (JSS) had the most significant effect on fatigue, while hours on duty had a larger effect than age but a smaller effect than sleep quality. Four variables studied were not significant predictors of fatigue and were not used in model creation: time awake, perceived stress, hours of sleep, and typically scheduled start time. Safely operating a flight involves weighing the implications of fatigue and other possible hazards resulting in many possible predictive factors. Heinrich’s domino theory was used to derive the fatigue factors in this dissertation. The significant predictor variables, age, hours on duty, and sleep quality form a potential “domino” for a fatigue- related accident. These fatigue factors may not cause an accident but could be a “domino” in a series of factors. While some fatigue factors have been studied, the factors studied in this dissertation have not previously been studied in the same way by creating a model with this population. Additionally, previous fatigue studies have not typically researched U.S.- based passenger-carrying pilots. Analyzing risks associated with fatigue in passenger- carrying pilots at commercial airlines is particularly complex because many factors can influence fatigue, including scheduling software, union contracts, and norms and practices. Airlines and regulators could use the prediction equation to potentially reduce fatigue-related risks. The equation created can predict fatigue in advance of scheduled flights and serve as a starting point for future fatigue researchers

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 354)

This bibliography lists 225 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during September, 1991. Subject coverage includes aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance