While acute cannabis intoxication has been shown to have demonstrable impact on psychomotor performance, these effects are typically mild and short-lived lasting at most one to three hours, and certainly not 24 hours, as claimed by the ONDCP. Moreover, unlike with alcohol, the accident risk caused by cannabis - particularly among those who are not acutely intoxicated - is often limited because subjects under its influence are generally aware of their impairment and compensate to some extent, such as by slowing down and by focusing their attention when they know a response will be required. This response is the opposite of that exhibited by drivers under the influence of alcohol, who tend to drive in a more risky manner proportional to their intoxication.

According to an analysis of on-road crashes released in September by an international expert panel: "The most meaningful recent culpability studies indicate that drivers with THC concentrations in whole blood of less than 5 ng/ml have a crash risk no higher than that of drug-free users." THC blood levels typically fall below 5 ng/ml in recreational cannabis users within 60 to 90 minutes after inhalation.

Nevertheless, St. Pierre reaffirmed NORML's stance that operating a motor vehicle under the influence of any controlled substance is unacceptable. "Responsible cannabis consumers never operate a motor vehicle in an impaired condition, regardless of whether that impairment is due to alcohol, cannabis or some other intoxicant or prescription medication," he said. "Public safety demands not only that impaired drivers be taken off the road, but that better objective measures of impairment be developed to more accurately identify drivers under the influence of drugs."

For more information, please contact either Allen St. Pierre, NORML Executive Director, or Paul Armentano, NORML Senior Policy Analyst, at (202) 483-5500. A comprehensive review of cannabis' impact on driving appears in NORML's report, "You Are Going Directly to Jail: DUID Legislation: What It Means, Who's Behind It, and Strategies to Prevent It," available online at:
http://www.norml.org/index.cfm?Group_ID=6492