The role of human capital and occupational factors in influencing driver safety has gained increased attention from trucking firms and policy makers. The influence of these factors, along with demographic factors, on the crash frequency of truck drivers is examined. A unique driver-level data set from a large truckload company collected over 26 months was used for estimating regression models of crash counts. On the basis of estimates from a zero-inflation Poisson regression model, results suggest that human capital and occupational factors, such as pay, job tenure, and percentage of miles driven during winter months, have a significantly better explanatory power of crash frequency than demographic factors. Relative to the zero-inflation and count models, results suggest that higher pay rates and pay increases are related to lower expected crash counts and to a higher probability of no crashes, all else held equal. Although the data come from one company, the evidence provided is a first step in examining the structural causes of unsafe driving behavior, such as driver compensation. These results may motivate other companies to modify operations and driver hiring practices. Also, the need for a comprehensive study of the relationship between driver compensation and driver safety is demonstrated.

Body odors (BOs) can convey social information. In particular, their effects are maximal when their presence is paired with meaningful social contexts. Static faces have been widely used as social stimuli. However, they miss a key feature of our phenomenological experience, characterized by multisensory dynamic stimulations. Here, we investigate how BO sampled from individuals experiencing a transitory anxiety state, (a) induce a stress response and (b) bias the recognition of dynamic facial expressions, compared with BO of relaxed individuals. Participants ( n=46) categorized the emotion of a face, morphing from a neutral expression to either an angry or happy expression, during exposure to either BO condition. In addition, their cardiac activity was measured. Exposure to anxiety BO increased the accuracy of dynamic facial recognition and reduced cardiac parasympathetic activity. These results suggest that in social situations that simulate part of the multisensory and dynamic features of real-life social contexts, anxiety BOs will induce a stress response in recipients, modulating both arousal and cognitive-emotional skills but facilitating emotional facial processing.

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With increasing speed limits and more light trucks penetrating the market, concern over their rollover risk is growing. In particular, the general public and automobile manufacturers would like to know if the increasingly popular sport utility vehicles (SUVs) are indeed safer than other vehicle platforms. The influences of various vehicle platforms on rollovers and driver injuries were investigated. Specifically, (a) the rollover intensities of SUVs vis-à-vis those of other vehicle types in single-vehicle crashes and (b) the severity of the resulting driver injury were explored. Data from a good-quality federally maintained database were used for crash analysis. The database contains a relatively clean stratified sample of police-reported tow-away crashes nationwide, and it contains detailed information about vehicle rollovers. Rollover intensity, captured by the number of quarter turns, was investigated by using weighted negative binomial models; injury severity, measured on the abbreviated injury scale, was examined by using weighted ordered logit models. New insights emerged about the factors that increase rollover intensity and injury severity. As expected, SUVs are more likely to roll over and therefore injure their occupant drivers more severely. However, SUVs also protect their drivers during collisions because of their greater crashworthiness. In fact, the SUV crashworthiness effect exceeds the rollover effect, on average. The implications of these findings are discussed.