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7 Exposure: Hours of Driving Risk: High-Drowsiness Episodes 7% 29% 39% High Risk Moderate Risk 47% Low Risk 64% 14% Figure 4. Relationship between exposure and drowsiness risk for high-risk, moderate-risk, and low-risk groups of drivers in the Hanowski et al. (2000) LSH truck driver study. Although the synthesis focuses primarily on heavy truck data on the prevalence of industry use of the methods as well drivers, it will also address long-haul motor coach drivers and, as subjective evaluations of them. The other expert survey to a limited extent, the phenomenon of high-risk transportation provided data only on expert opinion because the questions operators in general. Most safety interventions described in regarding use of the methods were not applicable. Findings the synthesis are carrier management related, and carrier safety from these surveys will be the centerpiece of this synthesis, managers are the major information source and intended although the authors concede that opinion surveys are not a audience for the synthesis. However, a few of the safety substitute for empirical data. approaches discussed are related to national regulatory and To supplement the expert survey, a focus group was con- enforcement issues. Appendix B reproduces the research ducted with staff members of the FMCSA, the major fed- project's Statement of Work. eral agency overseeing truck and bus safety. Supporting the The reasons and causes behind differential driver risk will survey and focus group findings is information obtained be explored in this synthesis. In the LSH study, for example, from literature reviews relating to the various personal cor- each driver was observed for only 1 week. It is possible that the relates of driver risk and to safety management methods. differences observed were related to long-term constitutional The literature reviews employed Transportation Research factors (e.g., enduring individual differences in aggression, Information System (TRIS) and other reference systems risk-taking, health), short-term personal factors (e.g., tempo- to identify relevant publications in the transportation liter- rary illness, lack of sleep due to a new baby at home), or sit- ature. Also reviewed were FMCSA research publications uational factors (e.g., weather, traffic variations, new delivery and research journals on traffic safety, psychometrics, and routes). The study collected no longitudinal data on drivers, industrial safety management. and few truck safety studies seem to have done so. The remainder of this synthesis will present the survey methodology and results, define and characterize the basic phenomenon of high-risk commercial drivers, explore fac- 1.3 APPROACH tors related to driver risk, and discuss operational safety management methods for addressing the problem. The syn- Information on high-risk commercial drivers and poten- thesis concludes with recommendations for R&D that might tial management solutions was obtained through several major be performed to address the many unanswered questions approaches. The primary vehicle for obtaining information relating to this issue, deepen current knowledge, and create was surveys. Two parallel survey forms were employed: one tools that industry can apply to ameliorate the problem. R&D for current CMV fleet safety managers and one for other is conceived broadly and may include many different types experts in motor carrier safety. The safety manager and other of initiatives undertaken by various parties and stakeholders expert survey forms were parallel in their questions and con- involved in motor carrier safety. If it is true that approxi- tent, but there was a key difference in the way the management mately 10% of commercial drivers are associated with one- effectiveness-related questions were asked. Safety managers third or more of safety risk caused by commercial drivers, were asked if they currently used the method and then, if "yes," there is clearly an opportunity to significantly reduce crash were asked to rate its effectiveness. Thus, these questions yield loss through focused efforts on these drivers.