Background: Pedestrian-vehicle collision is one of the most common traffic injuries worldwide. This study aimed to investigate the determinants of pedestrians' road crossing beliefs and behaviors in potentially risky situations using the Theory of Planned Behavior among Iranian young adults.Methods: This was a population-based study on a sample of 562 young adults aged 18 to 25 years living in Tehran, Iran. Data were collected by using a self-administered validated questionnaire including constructs of the theory of planned behavior and items of perceived risk and severity. The data were analyzed using independent t-test, analysis of covariance and multivariate analysis of variance.Results: From all the respondents, 17.8% reported that they had previous experience of vehicle-collision. Among the participants, those who had previous experience of vehicle-collision reported less safety behaviors in crossing the road than those who had not experience an accident. It was found significant differences between participants with and without a history of vehicle-collision for perceived risk (mean difference, adjusted multivariate P-value: -5.77, 0.027) and perceived severity (-6.08, 0.003), attitude toward traffic regulations (-6.34, 0.006), attitude toward behavior (-7.56, 0.005), perceived behavioral control (-5.20, 0.018), behavioral intention (-5.35, 0.046) and road crossing behavior in potentially risky situations (-5.37, 0.004). Conclusions: Previous unpleasant experience of vehicle-collision is not the only determinant of self-protective behaviors in road- crossing which indicate the role of cognitive and motivational factors such as, subjective norms, attitudes towards risk, feelings of invulnerability in case of facing with vehicle collision.