Authors reported that the use of cannabis, absent the simultaneous use of other drugs or alcohol, creates “only a fraction of the risks associated with driving at the legal 0.08 BAC threshold, let alone the much higher risks associated with higher levels of alcohol.” By contrast, they report that “the simultaneous use of alcohol and cannabis is linked to higher levels of driver impairment than either alone” – a finding that is consistent with much of the available literature.
They conclude, “The maximum risk for cannabis intoxication alone, unmixed with alcohol or other drugs, appears to be more comparable to risks such as talking on a hands-free cellphone (legal in all states) than to driving with a BAC above 0.08.” As a result, they suggest that as a matter of policy, “stoned driving alone (not involving alcohol or other drugs), should be treated as a traffic infraction rather than as a crime, unless aggravated by recklessness, aggressiveness, or high speed.”