Patterns of marijuana use and physical health indicators among Canadian youth

We examine how trajectories of marijuana use in Canadian youth (ages 15 to 28) are related to physical health indicators in adolescence and young adulthood. Youth were initially recruited in 2003 (N = 662; 48% male; ages 12 to 18) and followed for six waves. Five trajectories of marijuana use (Abstainers-29%, Occasional users-27%, Decreasers-14%, Increasers-20% and Chronic users-11%) were identified. Chronic users reported more physical symptoms, poorer physical self-concept, less physical activity, poorer eating practices, less sleep, and higher number of sexual partners during adolescence than other classes. Decreasers also reported poorer physical self-concept and poorer eating practices than abstainers. Other trajectory classes showed few significant health problems. Chronic users also reported more acute health problems (i.e. serious injuries, early sexual debut, higher number of sexual partners, greater likelihood of having a STI) in young adulthood than all other classes contributing to costs of healthcare. Youth who engage in early, frequent and continued use of marijuana from adolescence to young adulthood are at-risk of physical health problems in adolescence and young adulthood.     

Conditions for speeding behaviour: A comparison of car drivers and powered two wheeled riders

Against a UK background of decreases in collisions involving car drivers, motorcycle collisions are on the increase. To throw light on this process, this paper explores differences between motorcyclists and car drivers in the conditions for speeding behaviour. Some predictions derived from the model of Task-difficulty Homeostasis (TDH) were tested using self-report data from samples of older (>35 years), male car drivers (n = 269) and motorcyclists (n = 102). As predicted, riders were more likely to speed on rural roads and less likely to speed on urban roads, and, riders were much more likely to speed in daytime than at night.Riding a motorcycle offers opportunities for expressive use of the vehicle and riders are more likely to say they really enjoy riding fast. However amongst older riders this behaviour appears to be largely confined to daytime riding on rural roads. Compared with cars, motorcycles provide more of an opportunity to manoeuvre around obstacles in controlling task demand, rather than using speed as the primary controlling variable. Although this provides more options for the rider, it carries with it vulnerability to loss of control from variation in road surface adhesion and maintaining too high a speed.     

‘Not in my name’? The Italians and the war in Iraq

We performed a secondary analysis of data collected on a representative sample of Italians to study the attitudes and behaviours developed by the Italians with regard to war in general and the war in Iraq particularly. Moreover, we built a model predicting the probability of participating in pro‐peace demonstrations. The Italians seem polarized in their attitudes towards war and skeptical concerning the reasons for the attack on Iraq. Our models explained the probability of publicly showing one's opposition to the war in Iraq in terms of beliefs towards war in general, of attitude towards this conflict particularly, of frequency of newspaper‐reading and of values, showing that the sociodemographic and psychological variables played a significantly less relevant role. Copyright © 2007 John Wiley & Sons, Ltd.     

The interactive effects of temperament and maternal parenting on toddlers' externalizing behaviours

The present study aimed to determine the potential moderating effects of temperamental traits on the relation between parenting and toddlers' externalizing behaviours. For that purpose, this study examined the interplay between temperament and maternal parenting behaviours in predicting the level as well as the development of toddlers' externalizing behaviours. Participants were 115 boys (wave 1, M=16.9 months; wave 2, M=23.2 months) and their mothers, who were observed in a 13‐min structured play session at home. With regard to the prediction of the level of externalizing behaviours at wave 1, main effects were found for children's temperamental characteristics. In addition, maternal negative control interacted significantly with children's inhibitory control in predicting this level of externalizing behaviours. The findings with regard to the development of externalizing behaviours showed that the effects of maternal negative control and lack of maternal sensitivity were stronger for toddlers with a difficult temperament: maternal negative control and lack of maternal sensitivity were related to an increase in externalizing behaviours for temperamentally difficult children only. These results offer support for the goodness‐of‐fit hypothesis, stressing the idea that the effects of temperament and the social environment depend to a large extent on their interplay. Copyright © 2007 John Wiley & Sons, Ltd.     

Validation of the German version of the Driver Skill Inventory (DSI) and the Driver Social Desirability Scales (DSDS)

The psychometric properties of the new German versions of the Driver Skill Inventory (DSI) and the Driver Social Desirability Scales (DSDS) were examined. The DSI is a self-report measure assessing perceptual-motor skills and the safety motive as two important aspects of driving behavior. Self-report measures, however, are susceptible to socially desirable responding (SDR) which is why both general and specific driving-related SDR scales have been developed: Based on the Balanced Inventory of Desirable Responding (BIDR), the DSDS taps Driver Impression Management and Driver Self-Deception as two important aspects of SDR. In two validation studies with less experienced (N = 130) and experienced drivers (N = 1199), both inventories showed the expected two-factor structure and satisfactory internal consistency. In Study 1, self-ratings were compared with and confirmed by peer-ratings. In both studies, we accumulated evidence of convergent and discriminant validity for the German version of the DSI by correlating it with demographic, driving-specific, and personality measures, including the Big Five, Type A behavior, and sensation seeking. The DSI seemed to be only marginally contaminated by SDR.     

Analysing the influence of visible roadwork activity on drivers’ speed choice at work zones using a video-based experiment

The present study used a video-based experimental design to investigate the influence of visible roadwork activity on speed preferences at work zones. Four videos from real work zones in Norway were used. Two roadwork areas were filmed at two moments – with and without visible roadwork activity. A total of 815 drivers watched two videos and answered a questionnaire online. Participants stated speed preferences for both videos and then evaluated the influence of 17 common work zone elements on their speed choice. The results showed lower preferred speeds for the videos with visible roadwork activity. The elements considered by drivers to influence their speed included speed regulation (e.g. speed limit signs), transient motives (e.g. time pressure), flow pressure (e.g. speed of the rear driver) and situational conditions (e.g. road situation). Results from the regression analysis showed that visible roadwork activity was the strongest predictor of lower preferred speeds. Speed regulation and transient motives were also significant predictors of preferred speeds. Those who considered speed regulation more important to influence their speed choice at work zones were likely to state lower preferred speeds, while those who considered transient motives as more important were likely to state higher preferred speeds. These findings support the hypothesis that visible roadwork activity is an important factor for lower speed preferences at work zones. The main practical implication is that road authorities should consider various countermeasures to achieve safe driving speeds at work zones, not only roadworks warning signs.     

Identifying effects of driving and secondary task demands,passenger presence,and driver characteristics on driving errors and traffic violations – Using naturalistic driving data segments preceding both safety critical events and matched baselines

Researchers have identified various factors that likely affect aberrant driving behaviors and therefore crash risk. However, it remains unclear which of these factors poses the greatest risk for committing either errors or violations under naturalistic driving conditions. This study investigated important variables contributing to driving errors and traffic violations based on naturalistic driving data from the second Strategic Highway Research Program (SHRP 2). The analyzed driving segments preceded both safety critical events and matched baselines. Results showed that intersection influence, high-risk visually distracting secondary tasks, and the severities of the safety critical events were the main factors associated with driving errors. The primary factors linked to violations were intersection influence, persistent individual differences in driver behavior, and the severities of the safety critical events. Furthermore, the number of aberrant driving behaviors in trip segments preceding crashes was higher than in the matched segments unrelated to safety critical events. However, the most common aberrant driving behavior types in the respective segment groups appeared to resemble each other. This suggests that crashes became more likely due to drivers committing more violations and errors overall as opposed to drivers making one certain type of error or violation.     

Field operational test of a seatbelt reminder system: Effects on driver behaviour and acceptance

The long-term effects on driver behaviour and acceptance of a seatbelt reminder system were examined in an on-road study. The system was capable of detecting seatbelt use in all seating positions and produced a two-stage visual and auditory warning if occupants were unrestrained. The effects of this system were evaluated alone and in combination with two other intelligent transport systems: intelligent speed adaptation and a following distance warning system. Twenty-three fleet car drivers drove an instrumented vehicle (SafeCar) for at least 16,500 km as part of their everyday driving. The results revealed that driver and passenger interaction with the seatbelt reminder system led to large and significant decreases in the percentage of trips where occupants were unbelted, in the percentage of total driving time spent unbelted, and in the time taken to fasten a seatbelt in response to system warnings. The seatbelt reminder system was rated by drivers as being useful, effective and socially acceptable, and led to a decrease in drivers’ subjective workload. These results were found even though the baseline pre-exposure seatbelt wearing compliance rates among participants were high.     

Development of a pleasure in parenting scale

Two major components of parenting have been identified: warmth and control. There has been a great deal of work on the measurement of control, but there are not many measures of parental warmth. As part of an attempt to develop better measures of warmth, we developed a scale measuring parents' pleasure in carrying out routine caretaking acts with their children. This measure was then related to other measures of positive support such as observation, observer ratings and questionnaires. As there is evidence in the literature that quality of the environment interacts with parenting, we related the measure to measures of stress, observer ratings of quality of the home, marital interaction and parental mood. Finally, we examined the relation of child variables (attachment classification, temperament rating and observed behaviours) to the parents' ratings of pleasure in the child.