The motor carrier industry is vital to the United States economy. At the same time however, this country pays a high price in deaths, injuries, property damage, congestion, and pollution that result from truck accidents. While vehicle and driver deficiencies are major factors in truck accidents, a basic cause is that trucks and the highways on which they operate are not compatible.; The sharp curvature and downgrades on many highway ramps make them likely sites for truck rollovers. The hazard is exacerbated by the AASHTO guidelines to which the ramps are built, in that they are deficient for safe operation by trucks.; Every highway operating agency in the United States has safety enhancement programs in place. Typically, however, the effectiveness of these programs is diminished by reliance on incomplete and misleading accident data to identify sites and priorities for improvement.; A proactive approach to identification and prioritization of sites needing safety improvement is developed in this dissertation. It is based on a survey in which experts rate the relative extent to which deficiencies in each of the characteristics of a ramp might contribute to a truck rollover. The experts' ratings are derived from their knowledge of physics, highway design, and truck operations. There is no reliance on accident data, making this approach truly proactive.; Fuzzy mathematics is used in the synthesis of the survey results, in recognition of the fact that an opinion, however expert, is not precise. The final product of the survey is a set of ratings which describe the relative hazard of specific ramp and deceleration lane characteristics. These ratings can be used to rank all ramps in a jurisdiction in order of relative hazard. An example of the use of the ratings beyond a simple ranking is demonstrated in a cost-effectiveness analysis, where the ratings are used as a measure of effectiveness.
展开▼
