Lichenstein et al. 2012, Headphone use and pedestrian injury

Case series of 116 reports of headphone-wearing pedestrians injured or killed (around 70% fatal), with cases rising over the study period. The plausible mechanisms are auditory masking and inattentional blindness. A case series cannot establish incidence or relative risk, so it is a hazard signal rather than a quantified risk, but it supports caution about headphones near traffic. Moderate.