As laws surrounding marijuana use continue to evolve across the United States, the challenge of enforcing marijuana-related DUI laws has become more complex.
Unlike alcohol, where breathalyzer tests and standardized field sobriety tests (SFSTs) offer relatively straightforward methods for determining impairment, marijuana doesn’t lend itself to easy detection. This leaves police officers in Atlanta and across Georgia with the difficult task of determining whether a driver has been smoking marijuana and whether they are impaired.
As local DUI lawyers, we wanted to write a blog post to examine how police officers attempt to detect marijuana use in drivers, the limitations of current methods, and how defense attorneys can challenge marijuana DUI charges in Georgia.
We will explore the various signs officers look for, the tools at their disposal, and the legal complexities surrounding marijuana DUI cases.
Understanding Marijuana DUI Laws in Georgia
Georgia law prohibits driving under the influence of drugs (DUI), including marijuana. Under Georgia’s O.C.G.A. § 40-6-391, it is illegal to drive or be in actual physical control of a vehicle while under the influence of any drug to the extent that it renders the driver less safe to operate the vehicle.
Importantly, this "less safe" standard means that a driver does not need to be visibly impaired or over a certain THC (tetrahydrocannabinol) threshold, as with alcohol, to be charged with a DUI. The prosecution only needs to prove that the driver was impaired to the point of being less safe.
This legal framework creates significant challenges for both law enforcement and drivers. Unlike alcohol, where a specific blood alcohol concentration (BAC) of 0.08% establishes legal impairment (the so-called “per se” level), there is no universally accepted THC limit for driving. This makes identifying marijuana-impaired drivers more subjective and more reliant on an officer’s observations.
Signs Police Officers Look For When Suspecting Marijuana Use
When pulling over a driver suspected of marijuana use, officers use their training and experience to identify a combination of physical, behavioral, and environmental clues that suggest recent marijuana use. While some of these signs may point to impairment, others may simply indicate that the individual has used marijuana at some point, not necessarily that they are impaired while driving.
1. Odor of Marijuana
One of the most recognizable indicators of marijuana use is its distinct smell. Officers are trained to identify the odor of both burnt and unburnt marijuana, and smelling marijuana during a traffic stop often gives them probable cause to investigate further.
- Burnt Marijuana: If the officer detects the smell of burnt marijuana, especially inside the vehicle, it often suggests that the driver may have smoked marijuana recently. This can lead to further investigation, including questioning the driver or requesting them to undergo field sobriety tests.
- Raw Marijuana: The smell of unburnt marijuana may not necessarily indicate recent use, but it can lead to a search of the vehicle if the officer suspects possession of marijuana.
However, relying solely on the odor of marijuana can be problematic. With the rise of legal hemp products, which often smell like marijuana but contain very low levels of THC, the smell alone may not be a definitive sign of impairment. Furthermore, the odor can linger in a car or on a person’s clothing for hours, even after the effects of marijuana have worn off.
2. Physical Appearance and Behavior
Police officers often look for specific physical signs that are commonly associated with marijuana use. These include:
- Bloodshot or Glassy Eyes: Marijuana can cause the blood vessels in the eyes to expand, leading to redness or bloodshot eyes. Officers may also look for glassy or watery eyes, which can be another sign of recent marijuana use.
- Dilated Pupils: Marijuana use can cause pupils to dilate. Officers may shine a flashlight in a suspect’s eyes to observe their pupil reaction, although dilated pupils can also result from a range of other factors, including bright light, nervousness, or the use of other drugs.
- Dry Mouth: Commonly referred to as "cottonmouth," dry mouth is another physical effect of marijuana use that officers might look for during a stop. If a suspect appears to have difficulty swallowing or speaks with a noticeably dry voice, the officer may consider this a sign of marijuana use.
- Delayed Reactions or Slow Movements: Marijuana can impair coordination and reaction time, making individuals appear slow to respond or perform tasks. Officers may look for delayed reactions to questions or instructions, as well as sluggish physical movements.
- Lack of Focus: Marijuana can affect a person’s ability to concentrate. If a driver appears unfocused or struggles to follow the officer's instructions during the stop, this could be interpreted as a sign of impairment.
3. Erratic Driving Behavior
Similar to alcohol impairment, erratic driving is often a red flag for police officers. While marijuana affects drivers differently than alcohol, officers may still notice certain driving behaviors that suggest impairment, such as:
- Weaving Between Lanes: Failing to maintain a consistent lane position can be a sign of impaired judgment or slow reaction time.
- Slow or Delayed Responses to Traffic Signals: Drivers under the influence of marijuana may take longer than usual to respond to stop signs or traffic lights, or they may drive well below the speed limit.
- Wide Turns or Improper Signaling: Impaired drivers may make wide or sloppy turns or fail to use their turn signals correctly, further suggesting a lack of control over the vehicle.
4. Field Sobriety Tests (FSTs)
If a police officer suspects that a driver has been smoking marijuana, they may ask the driver to perform a series of field sobriety tests (FSTs). While these tests were originally designed to detect alcohol impairment, officers use them to assess a driver’s coordination, balance, and cognitive abilities, which may be affected by marijuana as well.
Some of the most commonly used field sobriety tests include:
- The Horizontal Gaze Nystagmus (HGN) Test: The officer asks the driver to follow a moving object (usually a pen or flashlight) with their eyes. They are looking for involuntary jerking movements of the eyes (nystagmus), which can indicate impairment. However, marijuana does not typically cause nystagmus, making this test less reliable for detecting marijuana use.
- The Walk-and-Turn Test: The driver is asked to walk heel-to-toe in a straight line, turn, and then walk back. The officer looks for balance issues, swaying, or an inability to follow instructions, which can suggest impairment.
- The One-Leg Stand Test: The driver is instructed to stand on one leg while counting out loud. Any loss of balance, hopping, or using arms for balance may indicate impairment. However, the effects of marijuana on balance may not be as pronounced as with alcohol, making this test less reliable for detecting marijuana use.
While these tests can provide officers with clues about a driver’s level of impairment, they are far from foolproof, especially when it comes to marijuana. Factors such as anxiety, fatigue, physical disabilities, and uneven terrain can all affect performance on these tests, leading to false positives.
5. Marijuana Paraphernalia in the Vehicle
If an officer notices marijuana paraphernalia in the vehicle, such as rolling papers, pipes, bongs, or marijuana residue, it can serve as probable cause for further investigation. While the presence of paraphernalia doesn’t necessarily mean the driver is impaired, it does suggest recent marijuana use.
Chemical Testing: The Challenges of Detecting Marijuana in a Driver’s System
While officers rely heavily on physical and behavioral clues to detect marijuana impairment, chemical testing is often used to confirm whether THC—the psychoactive compound in marijuana—is present in the driver’s system. However, unlike alcohol, where breathalyzers can provide immediate and accurate BAC readings, detecting marijuana impairment through chemical tests is far more complex.
1. Blood Tests
Blood tests are considered the most accurate method of determining THC levels in a person’s system, but they are not without limitations. THC can be detected in blood for several hours or even days after use, depending on the frequency of consumption. However, the presence of THC in the bloodstream does not necessarily correlate with impairment.
- Active THC vs. Metabolites: Blood tests measure both active THC (which causes impairment) and inactive THC metabolites (which do not cause impairment). This makes it difficult to determine whether a driver was impaired at the time of the stop or if they simply used marijuana at some point in the past.
- Time Delays: In most cases, officers cannot administer a blood test on the scene. Instead, the driver must be taken to a medical facility, which can result in significant delays. Since THC levels in the bloodstream drop rapidly after marijuana use, a delayed test may not accurately reflect the driver’s level of impairment at the time they were operating the vehicle.
2. Urine Tests
Urine tests are commonly used to detect drug use in general, but they are not ideal for detecting marijuana impairment. Like blood tests, urine tests can detect THC metabolites long after the effects of marijuana have worn off. This means that a driver could test positive for marijuana even if they were not impaired at the time of driving.
Additionally, urine tests cannot measure the amount of active THC in a person’s system, making it impossible to determine whether the driver was actually impaired when they were stopped.
3. Saliva Tests
Saliva tests are gaining popularity in some jurisdictions as a method for detecting recent marijuana use. These tests can detect active THC in the saliva, which may provide a better indication of recent consumption. However, saliva tests are not widely used in Georgia, and their reliability is still being studied. Moreover, saliva tests do not provide a precise measurement of impairment, as different people metabolize marijuana at different rates.
Defenses Against Marijuana DUI Charges in Atlanta
Given the challenges of detecting marijuana impairment and the subjective nature of many of the tests, defense attorneys in Atlanta have several strategies they can use to challenge marijuana DUI charges.
1. Challenging the Validity of Field Sobriety Tests
Field sobriety tests are not foolproof, and defense attorneys often argue that poor performance on these tests was due to factors other than marijuana impairment. For example, anxiety, fatigue, or poor weather conditions can all affect a person’s ability to perform these tests, leading to false conclusions.
2. Questioning Chemical Test Results
Because THC can remain in the body long after the effects have worn off, defense attorneys may argue that a positive blood or urine test does not prove the driver was impaired at the time of the stop. They can also challenge the timing of the test, arguing that delays in administering the test may have resulted in inaccurate readings.
3. Attacking Officer Observations
Much of a marijuana DUI case relies on the arresting officer’s observations of the driver’s behavior and appearance. Defense attorneys can cross-examine the officer to cast doubt on their observations, particularly if other explanations (such as allergies, medical conditions, or nervousness) could account for the driver’s appearance or behavior.
4. Arguing the Smell of Marijuana Is Not Probative
In cases where the arrest was based on the smell of marijuana, defense attorneys may argue that the odor alone is not sufficient to prove impairment. As more legal hemp and CBD products become available, the smell of marijuana can no longer be relied upon as a definitive sign of illegal marijuana use.
DUI Attorney
Determining whether someone has been smoking marijuana and whether they are impaired is a complex and subjective process. While police officers in Atlanta rely on physical clues, field sobriety tests, and chemical testing to detect marijuana impairment, none of these methods are foolproof.
The unique characteristics of marijuana and its lingering effects in the body make it difficult to definitively prove impairment at the time of driving.
As marijuana laws continue to evolve and public acceptance of its use grows, both law enforcement and legal professionals must navigate the challenges of ensuring road safety while protecting individuals from wrongful convictions. For those facing marijuana DUI charges in Atlanta, it is essential to consult with an experienced DUI attorney who can challenge the evidence, scrutinize the procedures used during the stop, and provide a robust defense in court.