Drivers' behaviour in intersections is not only influenced by the rules of priority in the intersection but also by the design of the intersection as well as the behaviour of other road users. If behaviours that supplement or contradict formal traffic rules become common in a particular traffic intersection, it is an indication that an informal traffic rule has been used. In the present study a sample of 1276 Swedish drivers (aged 18-74 years) responded to questions about how often they would yield to another driver in 10 hypothetical crossing situations. In all crossing situations the respondents were told that there was no major road, implying that they should always yield the right of way to traffic coming from the right (the right-hand ride). The results showed that drivers' reported behaviour varied over different intersections. As expected, the formal rule of priority (i.e., the direction from which the other driver was coming) was an important determinant for drivers' yielding behaviour. However, cues for informal rules such as the other driver's behaviour and road breadth were also of importance. Different groups of drivers could be identified according to their strategies of yielding behaviour. One group of drivers reported that they rarely yielded, whereas another group reported that they always did so. A third group complied with the right-hand rule most of the time, whereas the behaviour of a fourth group varied over intersections. The implications of the results and the appropriateness of the right-hand rule are discussed.
To examine the lifetime prevalence of trauma experiences and post-traumatic stress disorder (PTSD). Questionnaire-assessed PTSD, the type of traumatic event experienced, perceived trauma impact, and trauma frequency in 1824 randomly selected men and women. PTSD lifetime prevalence was estimated at 5.6% with a 1 : 2 male-to-female ratio, in spite of men reporting greater trauma exposure. The highest PTSD risk was associated with sexual and physical assault, robbery and multiple trauma experiences. Controlling for trauma type did not account for gender differences, while controlling for experienced distress did. The conditional probability for PTSD varied as a function of trauma type, frequency and impact of the event, with increased rates associated with prevalent trauma exposure and higher perceived distress. The latter accounted for the gender effect, suggesting that gender differences in PTSD in part represent a generally greater vulnerability to stress in women.
The aim of this study was to examine drivers’ view on their own speeding behaviour by focusing on belief based measures as suggested by the theory of planned behaviour. A sample of car owners (N = 162) completed a questionnaire including both direct and belief based measures of the latent variables in the theory of planned behaviour. The results showed that indices constructed with direct measures of attitude, subjective norm and perceived behavioural control made a larger contribution to the prediction of drivers’ intention to exceed the speed limits in both urban and rural environments, than did indices constructed with belief based measures. An extensive set of belief composites was produced and standard multiple regressions showed which of these contributed to the prediction of attitude, subjective norm and perceived behavioural control, as well as intention. The use of these findings is discussed.
Using structural equation modeling (LISREL 8.71), drivers' everyday speeding behavior was predicted using the theory of planned behavior as a frame of reference. One hundred and twelve test drivers had a device installed in their vehicles that continuously logged their speeding behavior in a large area under an extended period of time. The test drivers also completed a questionnaire including questions inspired by the theory of planned behavior. It was found that the independent variables stipulated in the theory afforded a level of prediction of drivers' self-reported speeding as well as of their logged speeding. Attitude towards speeding, subjective norm, and perceived behavioral control were significant determinants of self-reported speeding. Self-reported speeding, and subjective norm, but not perceived behavioral control, did then contribute to the prediction of drivers' logged speeding. The fact that perceived behavioral control did not directly contribute to the prediction of drivers' logged speeding may be due to the possibility that drivers with several years of experience already take into account the actual control they have over the target behavior. As the theory of planned behavior can be used as a frame of reference to predict drivers' everyday speeding behavior, it is suggested that the drivers might decide on a target behavior and in living up to this decision they continuously monitor their target speed during everyday driving.
Different systems of intelligent speed adaptation (ISA) have already been tested in the field and large-scale implementation is being discussed. But do we really know how these systems affect drivers during long-term use?Between 2000 and 2003 a total of 61 test drivers had an ISA speed warning device installed in their vehicles. Data from these trials show that,initially, the device greatly reduced the amount of time the majority of test drivers spent above the speed limit, and to some extent also reduced their mean speeds, but this effect decreased with time. Further analyses of 27 of the 61 test drivers then showed that the activation of the warning system affected different drivers in quite a homogenous way, with regards to attitude, subjective norm and self-reported behaviour, but not with regards to perceived behavioural control. After activation,long-term use did, however, affect the test drivers in a homogenous way with regards to attitude, subjective norm and self-reported behaviour, as well as perceived behavioural control. When considering these results it must be remembered that the device tested was a first generation ISA speed-warning device and with more research we think that different ISA-systems could be improved and the effects made more stable during long-term use.
The problem of game-vehicle accidents is discussed in terms of drivers' strategies for visual search in driving. To find possible measures for reducing the number of wildlife accidents, four studies were undertaken. Initially, two exploratory investigations were made: a survey of drivers' expectancies concerning moose in traffic and a study involving self reports of accidents and near accidents with moose. The results from these investigations give no evidence that drivers' experience, knowledge, orattitudes concerning moose are related to wildlife accidents.Instead they suggested that the visualsearch patterns of drivers might explain some of the effects obtained. In a series of field experiments, drivers' ability to detect moose dummies was explored, and in a final study, the effectiveness of the game crossing sign was investigated experimentally. The rsults were interpreted as evidence that in rural driving, drivers normally scan the view ahead in a systematic and almost automatic way which is not effective for the task of detecting moose. Drivers can easily change their automatic scanning into controlled search for animals but this search is demanding and can probably not be sustained for any length of time without feedback.
The power of two different theoretical frameworks, the theory of planned behaviour (expanded to include moral norm) and the driver behaviour questionnaire, to predict and explain drivers' speeding behaviour are compared and a combined model is suggested. One hundred and seventy-five test drivers, participating in a large-scale ISA-evaluation, answered a questionnaire in spring 2000. Based on the questionnaire data, logged speeding in autumn 2001 was predicted and LISREL-analysis was used for structural equation modelling. According to the results the two frameworks, alone or in combination, could explain between 38 and 53% of self-reported speeding and between 24 and 26% of logged speeding. A combination of the theory of planned behaviour and the driver behaviour questionnaire is presented and implications for the understanding of driver speed control are discussed.