States with marijuana decriminalization laws experienced a 13% increase in fatal car crashes among 15 - 24 year old males. There was no increase in females, and no increase in drivers over 24.
There also were no increase in fatal car crashes in states with medical marijuana laws. It is hypothesized that the reason for the difference between deciminalized states and medicalized states is that medical marijuana laws require that the marijuana only be used at home.
From the American Journal Of Public Health, March, 2020.
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