The Broader Impact of Mass Shootings on Traffic Fatalities

Mass shooting incidents receive widespread attention and create sudden distress not only within affected communities, but also in populations far from the event. Distraction and acute psychological stress can impair attention and judgment, raising the risk of unintended harms, such as traffic crashes.

To assess whether major mass shootings are associated with short-term increases in fatal motor vehicle crashes, as a potential extension of their broader mortality impact.

The Fatality Analysis Reporting System, a population-based registry of fatal US motor vehicle crashes, was used to measure traffic fatalities on the days before and after the top 10 deadliest shootings from 2008 through 2023. Using a quasi-experimental event study design that combined the days before and after mass shootings, changes in the mean additional risk of traffic fatalities attributable to mass shootings were estimated. The study team also examined when public internet search interest in "shooting" peaked relative to the mass shooting event, to assess whether the timing of this peak corresponded to changes in fatal motor vehicle crashes. These data were analyzed from January 2024 through April 2024.

Dates of 10 major mass shootings.

Traffic fatalities.

On the day following mass shooting events, public internet search interest in "shooting" peaked and traffic fatalities rose by an average of 14.3%, corresponding to 19.9 (95% CI, 12.7-27.1) additional deaths across the country. Increases in traffic fatalities were consistent across driver age and sex, vehicle occupancy, rurality, and lighting conditions, and persisted when restricted to states outside the affected state and its neighbors. Active shooter events that did not result in fatalities were not accompanied by increases in internet searches for "shooting" and traffic fatalities did not increase significantly, suggesting that public awareness of shooting events, and their impact on driving, differs meaningfully by event severity.

In this quasi-experimental analysis of major US mass shootings, major mass shootings were associated with a transient nationwide increase in fatal motor vehicle crashes on the day following the event. The excess fatalities observed on the day after these 10 events were equivalent in magnitude to approximately 75% of the deaths occurring during the events themselves, suggesting that the broader population-level mortality associated with mass shootings may extend beyond individuals who directly experienced the event.