Driving Under The Influence Of Marijuana – Impaired Driving

Driving Under The Influence of Marijuana

In almost all states, it is unlawful to operate a motor vehicle with any detectable amount of marijuana in your system. In states like California, any drug, whether it’s medical marijuana or an over-the-counter cough medicine, if it can be shown to impair a drivers ability to operate a motor vehicle safely, then the driver is in violation of Vehicle Code Sec. 23152 (a) driving under the influence, which is usually charged as a misdemeanor.

Other States

Other states refer to this type of traffic violation as “drugged” driving. The concern is that being under the influence of marijuana can, under certain circumstances, compromise a driver’s motor skill, reaction time, and even driving judgment.

Drugged driving has grown into a public health concern and has attracted attention from states that actively oppose the legalization of medical marijuana for medicinal purposes. As of 2013, there are over seventeen states and counting that permit the medical use of marijuana for qualified patients.

Chemical Tests

Drivers accused of driving under the influence are asked to choose between a blood, urine or breath test. Both blood and urine drug tests are used to determine whether a driver is under the influence of marijuana while driving. Breath tests however cannot detect the presence of THC, the active ingredient in marijuana, and therefore breath tests lacks both scientific credibility and evidentiary usefulness. This is why prosecuting driving under the influence of marijuana cases is so problematic. Unlike the presumptive blood alcohol level of .08 percent in dunk driving cases, there is no such presumptive standard for THC.

Blood testing is the only reliable and accepted method of determining actual THC levels in a driver’s bloodstream. The problem with urine tests however is that it does not reveal exactly when the driver actually used the marijuana. A single dose of THC produces metabolites in urine that can last up to thirteen days, which is long after the effect of marijuana has worn off. The issue with most drunk driving statutes is not whether the person tests positive for marijuana, but whether the driver was so impaired at the time of driving that the driver could not operate a motor vehicle safely.

Law enforcement and the medical community have been reluctant to state with specificity an actual THC level that establishes, beyond a reasonable doubt, that a driver was so impaired that operating a motor vehicle could not be safely accomplished. The medical community acknowledges the difficulty in arbitrarily selecting a numerical value, as opposed to alcohol impairment where one is presumptively impaired with .08 percent blood alcohol level in the system. Therefore, the driving risk associated with marijuana appears to be much less conclusive than is the case with alcohol and much more difficult to prove in a court of law.

Level of Impairment – Driving 

This issue is of particular concern to medical marijuana patients who use marijuana in compliance with state law and under a physicians expressed recommendation. This could mean that a driver could test positive for marijuana at the time of driving, but in reality, the marijuana had absolutely no effect on the drivers ability to operate the vehicle safely. In short, a driver, under this scenario, may test positive for marijuana but in fact, be absolutely sober. However, other studies show that marijuana can, depending on its strength, can indeed impair the driver from driving safely.

In summary, a persons right to use medicinal marijuana under a physicians instructions must be balanced against law enforcements duty of keeping our highways safe from the dangers presented by impaired drivers. From most accounts, the legal and growing use of medical marijuana will require state legislatures to rethink their driving laws as it relates to the lawful use of medical marijuana for medicinal purposes.

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