The CDC confirms the following statistics: - Marijuana/cannabis use is increasing, and 13% of nighttime/weekend drivers are reported to have marijuana in their system.- Marijuana users were about 25% more likely to be involved in a crash than drivers with no evidence of marijuana use. However, other risk factors - such as age and gender - may account for the increased crash risk among marijuana users, according to the CDC.- Removing alcohol from the equation, drugs (legal and illegal) are involved in about 16% of motor vehicle crashes.