# Interstate Highway Connections and Traced Gun Transfers Between the 48 Contiguous United States

## TL;DR

This study finds that guns used in crimes are transferred between U.S. states along major highways more than expected, highlighting the need for national policies to address gun trafficking.

## Contribution

The study identifies specific interstate highways associated with elevated gun transfers between states, beyond what is explained by geography alone.

## Key findings

- Guns used in crimes were transferred more than expected along major highways like I-15, I-25, and I-95.
- Northbound transfers along I-95 showed higher rates to New Jersey and Maryland.
- Interstate gun transfers contribute significantly to gun violence in the U.S.

## Abstract

This cross-sectional study investigates whether firearms used in crimes are transferred between states via major interstate highways at rates greater than expected based on spatial proximity.

Are firearms used in crimes transferred between US states connected via major interstate highways beyond what is expected based on spatial proximity?

In this cross-sectional study, between 2010 and 2019, 526 801 guns used in crimes in the 48 contiguous United States were traced to interstate purchases. Traced gun transfers were greater than expected along Interstate 15 southbound, Interstate 25 southbound, Interstate 35 southbound, Interstate 75 northbound and southbound, Interstate 95 northbound, Interstate 10 westbound, and Interstate 20 eastbound and westbound.

The findings suggest that guns used in crimes are transferred routinely between states connected via major interstate highways.

Interstate gun flow has critical implications for gun violence prevention, as gun transfers across state lines can undermine local gun control policies.

To identify possible gun trafficking routes along interstate highways in the US.

This repeated-measures, ecological, cross-sectional study used data from the Bureau of Alcohol, Tobacco, Firearms and Explosives from January 1, 2010, to December 31, 2019, to examine associations between interstate connections via 13 highways that each spanned at least 1000 miles and interstate traced gun transfer counts for the 48 contiguous United States. Analyses were completed in November 2023.

Characteristics of the origin states and the transportation connections between the destination state and the origin states.

The main outcome was the total count of guns used in crimes in each destination state per year that were originally purchased in the origin state. Bayesian conditional autoregressive Poisson models were used to examine associations between the count of guns used in crime traced to interstate purchases and interstate highway connections between origin and destination states.

Between 2010 and 2019, 526 801 guns used in crimes in the contiguous 48 states were traced to interstate purchases. Northbound gun transfers along the Interstate 95 corridor were greater than expected to New Jersey (incidence rate ratio [IRR], 2.80; 95% credible interval [CrI], 1.01-7.68) and Maryland (IRR, 3.07; 95% CrI, 1.09-8.61); transfers were similarly greater along Interstate 15 southbound, Interstate 25 southbound, Interstate 35 southbound, Interstate 75 northbound and southbound, Interstate 10 westbound, and Interstate 20 eastbound and westbound.

This repeated-measures, ecological, cross-sectional study identified that guns used in crimes traced to interstate purchases moved routinely between states along multiple major transportation routes. Interstate gun transfers are a major contributor to gun crime, injury, and death in the US. National policies and interstate cooperation are needed to address this issue.