In this study, we evaluated the severity of simulator sickness (SS) induced by a driving simulator, along with the effect of ginger (Zingiber officinale) and dark plastic film stripes (transparency=15%) on the displays as possible countermeasures.　After taking 1 g of ginger powder or glucose as a placebo, 16 men and 16 women participants drove a driving simulator twice, 10 minutes each time with a 10 minute interval.　The severity of SS was scored using Kennedy's Simulator Sickness Questionnaire (SSQ).　Analysis of variance revealed that all of the women's SSQ subscales were significantly higher than those of the men, suggesting that women are more susceptible to SS than men. SSQ-O (an SSQ subscale related to oculomotor malaise) and SSQ-TS (total severity) showed significant interaction between gender and the condition of with/without stripes.　Women reported significantly lower SSQ values when stripes were administered, suggesting that women's SS was alleviated by the stripes.　These scores of the women were significantly higher than those of the men.　No significant effect of ginger was found in SSQ-TS or in any of subscales.

This study examined differences in continuous risk perception between two groups of drivers, those with repeated traffic accidents and those without.　We presented twenty participants from each group a set of fifteen visual scenes shot from the passenger seat of a car; each scene was presented for 30 to 120 seconds.　We recorded continuous risk perception, using the risk estimation lever.　There were no significant differences between accident repeaters and safe drivers in variables that represent scenes such as maximum estimated risk, total estimated risk, or control frequency of the lever.　However, there were many differences in shapes of the mean estimated risk curve of each group.　Accident repeaters did not perceive risk from potential hazards such as blind intersections, and their risk perception from obvious hazards such as pedestrians, bicycles or other cars was delayed compared to that of safo drivers.　Mutual correlation analysis of mean curves of each group revealed the total delay of risk perception of accident repeaters in three scenes.　Safe drivers estimated risk from potential hazards by experience or knowledge.　However, accident repeaters tended to perceive risk only from the obvious traffic environment.

Traffic psychology researchers have discussed the relation between the self-assessment of driving skills and risk-taking behaviour.　From previous work, it can be hypothesized that drivers who overestimate their　roadcraft take more risks.　In this study, two investigations were carried out.　First, respondents (N = 201) were required to rate their own driving skills and report the extent to which they drive safely.　In addition, we conducted a naturalistic observation at a T-shaped intersection to compare the risk-taking measures and the self-estimate of driving skills (N = 36).　The questionnaire study demonstrated that drivers with three to five years of experience after acquiring their licences overestimated their driving skill and reported not to drive very safely.　The observation revealed that high-confidence about driving skills accounted for the tendency not to pay much attention to either side of the road and to make tight right turns.　The results suggest that accurate self-evaluation of one's own driving skill is necessary for preventing risk-taking behaviour and driving offences.