It is generally assumed that the side of traffic directionality has no influence on traffic safety. We claim that this is true only for neurologically healthy traffic participants. In ageing populations, the proportion of road users with brain lesions resulting from various causes may not be negligible. Due to the diverging hemispheric lateralisation of neuropsychological functions, this will result in more individuals having attention deficits for the left than for the right half of their environment. We speculate that this may have a particularly negative impact with right-sided traffic directionality, where manifold situations require drivers and pedestrians to pay attention especially to the left. The hemispheric asymmetry of attentional functions and its interference with traffic directionality may be taken into account in future strategies of accident prevention.