Criminal Law

How High Is Too High To Drive?

In 2013, Washington and Colorado passed laws allowing the recreational use of marijuana. Eighteen states plus the District of Columbia allow medicinal use of marijuana. Do these changes mean that you can now drive with marijuana in your system? Yes and no, depending on where you are and how much you use.

Just as you are not allowed to drive after drinking too much, you are not allowed to drive after using too much marijuana. Just how much is “too much” varies state by state, from “some” to “zero.”

What Are the Effects of Marijuana on Driving?

Even NORML (the National Organization for the Reform of Marijuana Laws) states: “Although cannabis is said by most experts to be safer than alcohol and many prescription drugs, responsible cannabis consumers never operate motor vehicles in an impaired condition.”

Marijuana use has been shown to impair performance on driving-simulator tasks and driving courses for up to three hours after use. Among these impairments are worse car handling, increased reaction time, impaired estimates of distance, sleepiness, lack of coordination and less vigilance.

When marijuana is consumed instead of smoked, it stays in the system longer than three hours. THC metabolites stay in the system much longer than THC itself.

Regular users (like medical marijuana patients) often perform much better on these tests than occasional users, even with higher amounts of THC in their systems.

How Marijuana Levels Are Measured

THC is the active component of marijuana. THC levels are not as easy to measure as blood alcohol concentrations, which can be measured at the roadside using a breathalyzer. Currently, officers use observations and standard field sobriety tests to indicate impairment. The driver is then arrested and brought to a hospital or diagnostic center for blood testing.

Except in extreme circumstances, drivers must consent to have their blood drawn or face losing their licenses. Researchers are working on saliva and fingertip tests that can be used roadside.

How Much Is Too Much?

The question then becomes how much THC in the blood is too much. In many states, “incapacity” or “impairment” observed by an officer that can be directly linked to drug ingestion is sufficient. In 15 states, anything above zero is too much. Some of these zero-tolerance states allow use of medical marijuana, which can mean a patient is never allowed to drive.

Other states set a per se limit, which allows a user to drive with a certain amount of THC or THC metabolite in his or her blood. Any amount above this limit is in violation of the law. The limit is 0.02 percent in Nevada and Ohio, for example, and 0.01 percent in Pennsylvania.

Washington and Colorado Laws

Washington and Colorado have paired legalization of recreational marijuana use with slightly higher per se limits at 0.05 percent, or 5 nanograms of THC per milliliter of blood. In Washington, this is an absolute per se limit. Anything over this limit is automatically considered DUID. In Colorado, a principal called “permissive inference” allows defendants to argue in court that they were not impaired at this level.

Call a DUID Lawyer

The issues surrounding an arrest for driving under the influence of marijuana can be complicated. Plus, the facts in each case and the law in each state are unique. This article provides a brief, general introduction to the topic. It is not legal advice. For more detailed, specific information about your situation, please contact a DUID lawyer.

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