According to the results of an in-depth study published in the American Journal of Public Health, fatalities on the roads actually decrease in states where medical marijuana is legal. This was confirmed by a team of researchers from Columbia University, who set out to see how legal medical cannabis had influenced road death rates over a 30-year period. “It is possible that this is related to lower alcohol-impaired driving behaviour in MML-states,” they concluded. Whatever the reason, it’s clearly having a positive impact.