US traffic deaths rise 14% the day after mass shootings, study finds

Researchers at Harvard University and other U.S. institutions analyzed traffic fatality data for the ten deadliest mass shootings between 2008 and 2023. Their study, published in JAMA Psychiatry, found a temporary increase in fatal car crashes the day following each incident, with an average rise of 14.3% – roughly 20 additional deaths nationwide. The authors suggest that intense media coverage and acute stress create a "contagion effect" that impairs drivers even far from the shooting locations. Internet searches for "mass shootings" peaked on the same days, supporting the link between public attention and hazardous driving behavior.

The findings highlight broader societal costs of mass‑shooting events beyond the immediate victims, indicating that psychological shock can translate into measurable public‑health risks across the United States.