According to a University of Iowa study, states that legalized medicinal marijuana saw a reduction in the cost of automobile insurance, which suggests that driving under the influence may not be as risky as driving under the influence of alcohol. According to Cameron Ellis, professor of finance at the University of Iowa (U of I), states that legalized medicinal marijuana between 2014 and 2019 saw rates decline by an average of $22 per driver in the first year after doing a ZIP code-level analysis of insurance data.