To understand how marijuana consumption impacts one's ability to operate a vehicle, it is helpful to know how the body processes marijuana. When marijuana is consumed, the chemical compound THC quickly manifests in the bloodstream. This is the psychoactive drug in marijuana, responsible for the "high" that the consumer feels.
Eventually, the body's metabolic process changes the chemical makeup of the THC, which becomes THC's active metabolite: Hydroxy-THC. At this point, one may feel slightly affected, but probably will not display signs of impairment. At the third stage, the body metabolizes the Hydroxy-THC into THC's secondary and inactive metabolite: Carboxy-THC. This metabolite is totally inactive and causes no cognitive impairment, but can remain in the blood for up to thirty days. The rate at which the body metabolizes THC into Hydroxy-THC and finally Carboxy-THC depends on the frequency of consumption, the amount and potency of marijuana consumed, and the consumer's metabolism.
Although studies suggest that it is safe for drivers with a small amount of Hydroxy-THC in their blood to operate a vehicle, many states (including Georgia) have adopted a zero-tolerance policy for any amount of THC or its metabolites in a driver's blood. Georgia law dictates that
"[a] person shall not drive...any moving vehicle while…there is any amount of marijuana…present in the person's blood or urine, or both, including [its] metabolites and derivatives."
So, draconian as it may sound, one could face conviction for driving under the influence of marijuana if any THC metabolites are found in his or her blood (remember, the metabolite Carboxy-THC remains in the bloodstream for up to thirty days).
If you are accused of driving under the influence of marijuana, your best bet for a favorable resolution is to retain an experienced attorney to diligently advocate for you. Your attorney can advise you regarding whether and when to consider submitting to a blood test or urinalysis to detect marijuana metabolites in your blood. Speak with an attorney who can offer expert advice and put you in the best position possible to defend your DUI charge(s).