Research shows marijuana legalization has not caused a surge in crash deaths

Critics of recreational marijuana argue that its legalization has led to more impaired drivers and higher crash rates, yet the research they cite is fundamentally weak. An Ohio investigation referenced by a major newspaper remains unpublished, uses selective testing, and cannot confirm drivers were high at the time of accidents. A highway-safety institute’s report attributes a 2.3 percent rise in fatal crashes to legalization, but re-plotting the data shows the post-legalization slope actually slowed.

A Canadian emergency-room study claims a 475 percent jump in cannabis-related collisions, but the raw figure involves only 125 cases over two years, relies on self-reported use, and adjusts for pandemic traffic patterns in a dubious way. Interviews with the study authors reveal the work is still in progress or defended despite methodological criticisms. Consequently, the narrative that legal weed has overwhelmed hospitals or made roads more dangerous lacks credible empirical support.