Investigating the psychometric properties of Diving Moral Disengagement Scale (DMDS) : A cross-sectional study in Tehran

Introduction: Comparing aggressive behavior in everyday life and driving context shows that driving can increase the aggressive manner. This anger and rage leading to serious harm for oneself or other people, in addition it can sometimes causing immoral and obscene behavior. This issue that “why good people do bad, inhuman and unethical things without feeling guilty” discussed in bandura’s moral disengagement mechanism theory. The purpose of this study was to measure psychometric of aggressive driving moral disengagement scale.  Methods: The method of this cross-sectional research was descriptive-correlational. In this study, firstly we prepared a questionnaire in 32 items about moral disengagement on driving. And after reviewing the face and content validity by familiar experts to subject, it was reduced to 24 items. Its reliability was also confirmed in a small group of drivers (a=0.89). To examine the structure validity, 135 drivers completed the questionnaire in online way in Tehran in 2020. Finally, the data was entered in SPSS 23 software. For the structure validity was applied the exploratory factor analysis with principal component analysis (PCA) method with Varimax rotation. Results: In all 135 drivers who participated, 79 (58.5%) of them were male and 56 (41.5%) were female. The mean age of the drivers was 44.31. Factor analysis clearly distinguished 17 items in four factors, namely: dehumanization, moral justification, shifting responsibility, and distorting outcomes. The results of reliability analysis with Cronbachchr(chr('39')39chr('39'))s alpha method showed that these four factors have a good coefficient of internal consistency. Conclusion: The driving moral disengagement scale.as a reliable and valid tool can be used with other psychological studies and high-risk behaviors of drivers’ reviews. These studies can increase our understanding of moral justifications, attribution of bad behavior and irresponsibility while driving.