John J. Wright

Information Technology Resources

Determining if a Driver was under the Influence of Marijuana while Driving still a Big Challenge to Authorities

Posted by on Feb 3, 2014

In the fall of 2012, besides choosing who should be President of the United States, Americans in some states were also asked to cast another vote on whether to legalize possession and/or recreational use of pot or marijuana. Their “yes” vote, though, entailed another decision: that drivers who would prove positive of having at least five nanograms (one thousand-millionth of a gram) of THC per milliliter of blood would be judged as being under the influence (much like the 0.08% blood alcohol content for DUI/DWI). Five nanograms, studies show, increases the risk of accident as this level causes driver impairment.

Thus, despite greater freedom in possessing and using the drug, if you get charged with Marijuana DUI, you will still end up in big trouble. Driving under the influence of marijuana is held illegal in all 50 states and whoever is caught is bound to suffer penalties.

Marijuana, also called Mary Jane, cannabis, pot, dope, grass, ganja, weed, and bud, contains delta-9-tetrahydrocannabinol or THC, its chief psychoactive ingredient, which can impair the driver and which can remain in the driver’s system for hours or even months, depending on his/her tolerance to the drug, the concentration of THC and the amount of the drug he/she has used.

Though the above factors can definitely determine if the driver has used marijuana or not, there is no device yet that can manifest the level of THC in his/her blood or when exactly he/she used the drug. Tests using chemicals are, likewise, limited to determining if dope was used, not when it was consumed. These, therefore, will make it hard to prove whether or not the driver was under the drug’s influence while he/she was driving.

On-the-spot determination (after being pulled over) by a traffic enforcer if the driver is under the influence of dope, includes the driver’s performance on Field Sobriety Tests or FSTs, the driver’s physical appearance, the driving pattern or how the vehicle was driven, and the presence of marijuana in the blood as revealed by a chemical test.

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