Theses and Dissertations (VTTI)

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Browsing Theses and Dissertations (VTTI) by Subject "Commercial Vehicle Operations"

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    Effects of In-Vehicle Information Systems (IVIS) Tasks on the Information Processing Demands of a Commercial Vehicle Operations (CVO) Driver
    Blanco, Myra (Virginia Tech, 1999-12-10)
    This study was performed with two main goals in mind. The first goal was to understand and predict "red-lines" and "yellow-lines" in terms of what the CVO driver can process without hindering the primary task of driving. The second goal was to collect conventional secondary task data for CVO driving performance. An on-the-road experiment was performed with the help of 12 truck drivers. Type of task, presentation format, information density, and age were the independent variables used in the experiment. The 22 dependent measures collected were grouped into the following categories: eye glance measures, longitudinal driving performance, lateral driving performance, secondary task performance, and subjective assessment. The findings of this study strongly suggest that paragraphs should not be used under any circumstance to present information to the driver while the vehicle is in motion. On the other hand, the Graphics with Icons represent the most appropriate format in which driving instructions and information should be presented for IVIS/CVO tasks. In order to avoid a high visual attention demand to the driver due to a secondary task, only simple search tasks with the most important information shall be presented. Although the suggested format, type of task, and information density represent a higher visual attention demand than a conventional secondary task, these characteristics seem to bind a task with a moderate attentional demand. Other combinations of format, type of task, and information density will cause an increase in the driver's attentional demand that will consequently deteriorate their driving performance causing unsafe driving situations.
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    The Impact of Local/Short Haul Operations on Driver Fatigue
    Hanowski, Richard J. (Virginia Tech, 2000-05-23)
    Massie, Blower, and Campbell (1997) indicate that trucks that operate less than 50 miles from the vehicle's home base comprise 58% of the trucking industry. However, despite being the largest segment, research involving local/short haul (L/SH) operations has been scant. In fact, little is known about the general safety issues in L/SH operations. As a precursor to the present research, Hanowski, Wierwille, Gellatly, Early, and Dingus (1998) conducted a series of focus groups in which L/SH drivers provided their perspective on safety issues, including fatigue, in their industry. As a follow-up to the Hanowski et al. work, the effort presented here consisted of an on-road field study where L/SH trucks were instrumented with data collection equipment. Two L/SH trucking companies and 42 L/SH drivers participated in this research. To the author's knowledge, this is the first in-situ data collection effort of its kind with L/SH drivers. The analyses focused on determining if fatigue is an issue in L/SH operations. Of primary interest were critical incidents (near-crashes) where drivers were judged to be at fault. The results of the analyses indicated that fatigue was present immediately prior to driver involvement in at-fault critical incidents. Though it is difficult to determine why fatigue was present, the results seem to indicate that much of the fatigue that the drivers' experienced was brought with them to the job, rather than being caused by the job. There are four basic outputs of the Phase II research: (1) a description of the L/SH drivers who participated, (2) a description of critical incidents, (3) a determination if fatigue is an issue in L/SH trucking, and (4) the validation of the fatigue factors cited in Hanowski et al. (1998) using a proposed fatigue model. These four outputs culminate in a set of pragmatic guidelines to address fatigue and other safety issues in L/SH operations. Five guidelines are proposed that are directed at: (1) driver education with regard to on-the-job drowsiness/inattention, (2) driver education with regard to sleep hygiene, (3) driver training, particularly for novice L/SH truck drivers, (4) driver screening, and (5) public monitoring of L/SH driver performance.