A lot of (visual, auditory, social, emotional, psycho-motoric, intellectual and cognitive) competences are needed for safe traffic participation. Traffic competences develop during childhood and youth and there is a close relationship to brain maturity. Based on extensive literature analysis a comprehensive tabulation of empirically based developmental milestones was developed by gathering knowledge from different disciplines (Schützhofer, Rauch, Knessl & Uhr, 2015, Schützhofer, 2017). These milestones of traffic competences, forming the core of this paper, are now extended and updated to answer the question of how children can be aware of the traffic environment at a certain age and what this implies for their safe traffic participation. This article forms the framework for the tabulation and focuses on the development of visual competences and hazard perception. Based on the results of the literature review, it will be discussed if there are implications for infrastructure planning as well as for traffic education. Main objective of this research is the development of recommendations for age dependent safe traffic participation that do not under-or overstrain children and give them the chance to have their own active traffic experiences within adequate and safe borders. This traffic psychological and developmental psychological knowledge is essential in various fields. The results address policymakers, traffic managers, transport planners and technicians and help them to appreciate that children are not small adults and adaptions of the existing traffic environment are needed. They can also be a starting point for the development of traffic safety workshops for pedagogues, parents and police officers as in Austria.