At a glance:
Mass shootings cause distress nationwide. Examining national data and internet search trends, Harvard Medical School researchers have discovered the disruption also manifests on the roadway.
Anupam Jena , the Joseph P. Newhouse Professor of Health Care Policy in the Blavatnik Institute at HMS and HMS professor of medicine at Massachusetts General Hospital, and team examined the 10 deadliest mass shootings in the United States between 2008 and 2023.
Incidents on public holidays were excluded, as traffic patterns would have already been disrupted. The Marjory Stoneman Douglas High School shooting in Parkland, Florida, occurred on a Valentine’s Day and was not included in this study.
Researchers began the study period in 2008 to account for widespread smartphone and social media use, which quickens the spread of news. They analyzed internet search patterns using Google Trends and identified that public internet search peaked the day following each shooting.
The research, published July 15 in JAMA Psychiatry , used data from the Fatality Analysis Reporting System (FARS), a nationwide registry of fatal traffic accidents. Looking at the 10 days before and after a mass shooting, the researchers showed that traffic fatalities increased by 14.3 percent the day after the mass shooting, amounting to nearly 20 additional deaths — a pattern that was consistent across the country.
There was no increase following active shooter events where there were no fatalities.
The researchers believe the acute psychological stress can impair attention and judgment, although the study does not distinguish between psychological distress and media distraction. The findings add to the growing evidence base surrounding the potential impacts of driver distraction on motor vehicle collisions.
Authorship, funding, disclosures
Jena is senior author of the paper. Additional authors are Vishal R. Patel, Christopher M. Worsham, and Michael Liu.
There was no funding for this study.
Jena reports receiving (in the last 36 months) consulting fees unrelated to this work from Analysis Group; income unrelated to this work from hosting the podcast Freakonomics, M.D .; authorship income from The New York Times , Los Angeles Times , and The Wall Street Journal ; book rights to Doubleday Books; and speaking fees from the Harry Walker Agency. Jena is also an unpaid board member of the United Network for Organ Sharing (UNOS). Worsham reports receiving (in the last 36 months) consulting fees unrelated to this work from Alosa Health, Analysis Group, Berkshire Hathaway Home Companies, Chronius, FVC Health, NuvoAir, Simbo, Substack, Tell Health, Time, The New York Times , The Wall Street Journal , and FVC Health and income unrelated to this study from book rights to Doubleday Books and speaking fees from the Harry Walker Agency.
JAMA Psychiatry
15-Jul-2026