Electric vehicles reduce driver injury severity but increase risk for other road users

Electric vehicles (EVs) are typically 20% heavier than conventional internal combustion engine vehicles because of their dense battery packs and reinforced structures. While this additional mass shields EV occupants, it transfers disproportionately greater kinetic energy to other road users during collisions, exacerbating their injury severity. Here, we quantify this critical safety disparity using data from over 300,000 two-vehicle collisions in California. We find that driving an EV reduces the occupant’s risk of serious injury or fatality by 18%. However, it significantly elevates the corresponding risk for occupants of colliding vehicles by 13%—an effect driven almost entirely by vehicle weight. Economically, these externalized accident costs offset approximately one-third of the environmental climate benefits of EVs, indicating that while EV adoption still yields a net gain in social welfare, it introduces profound safety inequities. As vehicle electrification accelerates globally to mitigate climate change, our findings highlight an urgent need for policies regulating fleet weight to ensure equitable road safety.