At 4:20 pm, on a warm South Florida evening, a trooper stops a vehicle driven by Mary Wanna. Her vehicle had a broken tail light. When the trooper approaches, he smells the odor of marijuana emanating from inside the vehicle. Mary appears to be lethargic and has the odor of an alcoholic beverage coming from her breath. Her eyes are glossy and bloodshot and her movements are slow. The trooper asks the driver if she has been drinking. The driver responds, “No, not recently.” The trooper requests that the driver exit her vehicle. Mary slowly exits and seems to have difficulty standing without swaying. The trooper requests that she perform some “field sobriety exercises,” (also known as “roadside tests”). The trooper concludes that Mary “failed each and every test given.” He places her under arrest for DUI (Driving Under The Influence). Back at the station, Mary is asked to blow into the breath machine and blows a .000, indicating that no alcohol is present in her system. The officer then requests that Mary provide a urine sample. Several weeks later, the lab report is made available and it reveals the presence of THC, the active ingredient in marijuana. Can prosecutors prove their case?
As you’ve likely heard, more states around the country have been legalizing marijuana, both for recreational and medical use. Florida recently legalized marijuana for medial purposes. With more people in our state using pot, we will likely see more folks driving while under the influence of marijuana. That’s why the Florida Highway Patrol has been pushing their campaign entitled, “Drive Baked, Get Busted”. The question is, how can prosecutors prove a marijuana based DUI case?
First, it’s important to note that in an alcohol based DUI, law enforcement use a breath machine known as the Intoxylizer. If working accurately, the alcohol breath machine (or “instrument” as prosecutors like to call it) can reveal precisely how much alcohol is in one’s system at the time they blow. If a person blows over a .08, then there’s a presumption that they were impaired at the time of driving. A similar device to detect the marijuana content in one’s system does exist. Many states have an instrument that will measure exactly how many nanograms of tetrahydrocannabinol (THC), the active ingredient in pot that causes impairment, is in one’s system. Florida does not have such a device in use. Instead, arrestees that are suspected of being impaired due to marijuana are asked to provide a urine sample. Typically, it takes the prosecutors a month or two to receive the results from their lab. All the report will indicate is whether THC was detected. Exactly how much was in one’s system or how long it was there is information that cannot be determined from current Florida tests. That opens the door to many arguments by skilled defense attorneys.
Prosecutors often will attempt to secure their DUI conviction by arguing that the observations made by the officers are sufficient. They frequently maintain that physical features like glossy blood shot eyes, dilated pupils, twitching, swaying, slurred speech, a tired demeanor, etc. all are indicators that the person was high at the time of the arrest. While that may be true, it’s not difficult to devise several reasonable hypothesis of innocence to undermine the State’s case.
I’ll often argue to jurors that the physical features that are present in someone who is stoned is similar to someone who is sleep deprived. Furthermore, the presence of THC in one’s urine could be the result of having smoked weed as far back as thirty days earlier. Even when the case involves the use of a Drug Recognition Expert (a DRE), who is typically called in to perform specialized physical tests to determine marijuana impairment, prosecutors still have challenges proving these cases.
The marijuana based DUI cases that are strongest for prosecutors typically include an admission by the driver that he/she recently ingested the substance. Alternatively and/or in addition, if officers observe smoke in the vehicle or a warm pipe indicative of recent use, the prosecution’s case is stronger.
DWS (Driving While Stoned) cases are very challenging to prove. While challenging, they aren’t impossible as long as prosecutors have compelling facts evidencing recent marijuana use. As for Mary Wanna, I believe with those set of facts, prosecutors will have a difficult time proving their case.