1,400 additional traffic fatalities in the U.S. each year likely accounted for by the legalization of marijuana

I bet the actual fatality numbers are higher! The popular legalization of so called recreational drugs has consequences!

Will these drugged offenders be sanctioned harsher than sober drivers? Don't bet on it, but clearly they should!

"The number of additional traffic fatalities in the U.S. each year likely accounted for by the legalization of marijuana, a 2023 study found. Law enforcement is racing to identify drivers who are impaired by cannabis. Police rely on extra training and saliva tests, but those check only for recent marijuana use. In the blood, the concentration of THC, the psychoactive compound that makes people high, falls even as impairment increases, unlike alcohol, where levels are more closely related to how compromised drivers are, toxicologists say."

From the highlights and abstract:

"Highlights

• TWFE [traditional two-way-fixed-effects] methods are inadequate for policy evaluation.

• Traffic fatalities increase by 2.2 per billion miles driven after retail legalization.

• States who legalized earlier experienced larger traffic fatality increases.

Abstract

Background

This study examines the effect of retail recreational marijuana legalization on traffic fatalities using the most current data available and recent advancements in difference-in-difference estimation methods ...

Method

A modified difference-in-difference (CS-DID) is used to estimate the effect of recreational marijuana legalization on traffic fatalities reported in the Fatality Analysis Reporting System (FARS). Difference-in-difference regression models are run at the state-year level, using data from 2007 through 2020, and compared to estimates using traditional two-way-fixed-effects (TWFE) models.

Results

Consistent with past studies, results from conventional TWFE suggest traffic fatalities increase at a rate of 1.2 per billion vehicle miles traveled (BVMT) after retail of recreational marijuana begins. However, using the CS-DID model, we find slightly larger average total treatment effects (∼2.2 fatalities per BVMT). Moreover, the size of the effect changes across time, where cohorts “treated” earlier have substantially higher increases than those who more recently legalized.

Conclusion

Traffic fatalities increase by 2.2 per billion miles driven after retail legalization, which may account for as many as 1400 traffic fatalities annually. States who legalized earlier experienced larger traffic fatality increases. TWFE methods are inadequate for policy evaluation and do not capture heterogeneous effects across time."

The Wall Street Journal What's news

Revisiting the effect of recreational marijuana on traffic fatalities (open access, I presume this is the referenced study)