Nearly 5% of US adults reported driving under the influence of marijuana in 2018, according to a CDC report.

As a growing number of states legalize marijuana, concerns about a potential increase in impaired driving have emerged. As of January 2020, recreational marijuana was legal in 11 states and medical marijuana was legal in 33 states. Using marijuana has been associated with impaired psychomotor and cognitive function while driving and some evidence suggests an increased risk of crashes. A 2014 survey by the US Substance Abuse and Mental Health Services Administration found that about 3.2% of US residents aged 16 to 25 years reported driving under the influence of marijuana.

The latest CDC data found that 4.7% of US residents aged 16 years or older reported driving under the influence of marijuana. Additionally, 8% reported driving under the influence of alcohol and 0.9% reported driving under the influence of illicit substances other than marijuana. Males were more likely than females to report driving under the influence of marijuana (6.2% vs 3.2%). Marijuana-impaired driving was also more prevalent among younger age groups, with 12.4% of drivers aged 21 through 25 years and 9.2% of those aged 16 through 20 years reporting this behavior.

根据疾病预防控制中心的一份报告，2018年有近5％的美国成年人报告说在大麻的影响下开车。

随着越来越多的州将大麻合法化，人们开始担心驾驶不便的可能性会增加。截至2020年1月，休闲大麻在11个州合法，医用大麻在33个州合法。开车时使用大麻与精神运动和认知功能受损有关，一些证据表明发生撞车的风险增加。美国物质滥用和心理健康服务管理局（US Substance Abuse and Mental Health Services Administration）于2014年进行的一项调查发现，约有3.2％的16至25岁的美国居民报告说是在大麻的影响下开车。

美国疾病预防控制中心（CDC）最新数据显示，在美国16岁以上的居民中，有4.7％的人报告说是在大麻的影响下开车。此外，有8％的人报告说是在酒精的影响下开车，而有0.9％的人报告是在大麻以外的非法物质的影响下开车。在大麻的影响下，男性比女性更有可能报告驾驶行为（6.2％对3.2％）。大麻受损的驾驶行为在年轻年龄段人群中也更为普遍，年龄在21至25岁之间的驾驶员占12.4％，而年龄在16至20岁之间的驾驶员占9.2％。