A new study published in JAMA Psychiatry has found that traffic fatalities in the United States increase following deadly mass shootings. The research, conducted by Harvard Medical School, analyzed traffic deaths before and after mass shootings from 2008 to 2023 and observed a significant rise in fatal car accidents the day after major incidents.

Focusing initially on the 10 deadliest shootings during that period—events in which between 13 and 58 people were killed—the study found that traffic fatalities surged by an average of 14.3 percent the day following these attacks. This increase translates to roughly 20 additional road deaths compared to the average number recorded during the 10 days preceding each event. Expanding the analysis to 100 of the most severe shootings revealed a smaller but consistent rise in traffic deaths.

Dr. Anupam B. Jena, the study’s senior author and a physician-economist at Harvard Medical School, suggested a likely causal connection between mass shootings and the increase in traffic fatalities. He explained that the combination of driver distraction—from mobile phone alerts, incoming calls, and breaking news coverage—alongside the psychological toll of hearing about a mass shooting, may impair driving focus and contribute to a higher risk of accidents.

However, some experts expressed reservations about the study’s conclusions. Jaclyn Schildkraut of the Regional Gun Violence Research Consortium criticized the methodological basis for attributing nearly 20 additional motor vehicle deaths directly to mass shooting coverage, warning that it is “methodologically unsound and impossible to validate.” Other scholars initially expressed concern about the limited sample size of the most deadly shootings examined but acknowledged the authors’ efforts to ensure robustness through broader analyses.

James Densley, a researcher at the Violence Prevention Project Research Center at Hamline University, described the study as a “well-built natural experiment,” finding the pattern of increased fatalities difficult to dismiss as coincidental. He noted parallels with other research showing spikes in car crash deaths connected to stressful societal events such as income tax deadlines.

The study also aligns with previous research indicating that mass shootings have broad mental health impacts, including increased antidepressant prescriptions among young people. Dr. Jena emphasized the psychological consequences of mass shooting alerts, explaining that drivers may be mentally preoccupied by the tragedy at the same time they need to maintain focus on the road.

While the findings do not establish a definitive cause-and-effect relationship, the study highlights potential indirect public safety costs associated with mass shootings beyond the immediate violence, suggesting an area for further investigation.