Currently, various driver assistance systems are under development to make driving safer.　However, the potential effect on safety of such systems might be reduced because of risk compensation behavior by drivers.　This study investigated the effect of driver assistance systems on risk compensation behavior using a computer display.　The effect of different information providing strategies at an intersection was compared.　The experimental conditions were (1) normal information, (2) detailed information, (3) restricted information, and (4) no information.　The results showed that participants “looked” significantly less in the “detailed information” condition than in other conditions.　The difference in the number of collisions was not significant between this condition and the “no information” condition, while the number of collisions was significantly reduced in the “normal” and “restricted” information conditions.　These facts imply that the degree of risk compensation might vary depending on information providing strategies.　Additionally, we propose a hypothetical model for promoting/ preventing risk compensation behavior based on the results of this experiment.

This article is aimed to demonstrate relations between drivers' estimation of risks and their driving behaviors in a situation where drivers are able to control a speed of their vehicle freely in driving simulator.　Thirteen participants were asked to drive a simulator and react to risky situations with possibilities of rear-end collisions and cross-path collisions on the simulated scenarios.　Participants were also instructed to evaluate the risks of those traffic situations.　The results showed that even when drivers could control a speed freely, they estimated the risks of some situations with possibilities of rear-end collisions lower because of specific factors in the traffic situations.　Moreover, the drivers' lower risk estimation led to smaller time headway to lead vehicle at a cruising speed and, delayed their reaction to the imminent risks of rear-end collision.　In contrast, drivers' delayed reactions caused by their lower estimation were not observed in the situations with the possibilities of a cross-path collisions.　These results were consistent with the ones found in the author's previous study which were carried out under the condition that the drivers could not be allowed to control the vehicle speed and distance headway in the simulator.

The present work describes the basic principle and quality assurance of medical-psychological examnation for drink-drive offenders in Germany.　Medical-psychological examination is carried out for those whose driving license has been revoked as a consequence of serious traffic offence or traffic accident.　In case of drink driving it becomes obligatory when, for example, Blood Alcohol Concentration 0.16% (0.8 mg/1 in breath) or higher is detected.　Trained specialists in traffic psychology and traffic medicine assess whether an examinee is free from physical/ psychiatric problems that would deteriorate his/ her driving performance, or whether he/ she has overcome psychological problems that led to excessive drinking or inappropriate coupling of drinking and driving, and therefore is deemed to be fit to drive safely.　Assessment criterion is outlined based on relevant literature and is contrasted with Japanese measures for drink-drive offenders.

The rate of young people in bicycle accidents is dominant not only in casualties but also in violator against the traffic law.　This paper aims to figure the cycling behaviors of junior and senior high school students, referring to their general traffic experiences, their knowledge of traffic law on bicycle and their behaviors in daily life.　A questionnaire survey was conducted in Shiga prefecture and total of 1,218 junior high school and 1,096 high school students of both sex answered the questionnaire.　The results showed that their understanding of traffic law was not sufficiently correct and that corresponded to their risky cycling behaviors, inadequate general traffic behaviors and their socially undesirable behaviors in daily life.　Based on these results, the necessity of education for the accurate traffic law and nourishment of sociality in daily life for the young people are suggested.