Key Takeaways
- Marijuana DUI cases in Maryland are not proven with a standard breathalyzer.
- Legal cannabis use does not protect a driver from DUI charges.
- THC can remain detectable after impairment has worn off.
- Police often rely on officer observations, field sobriety tests, DRE evaluations, and blood testing.
- A positive THC test does not automatically prove impairment at the time of driving.
Unlike alcohol-related DUI cases, there is no marijuana equivalent of a breathalyzer that can reliably measure impairment at the time of driving. In Maryland, police and prosecutors must rely on observations, field sobriety tests, blood testing, and other evidence to argue that a driver was impaired by cannabis. Because adult marijuana use is legal under Maryland law, many drivers are surprised to learn they can still face DUI charges.
Can You Get a DUI for Marijuana in Maryland?
Yes. Maryland law prohibits driving while impaired by marijuana, even though adults can legally possess and use cannabis under certain circumstances. The key issue is not whether marijuana use was legal. The issue is whether the State can prove that marijuana impaired your ability to operate a vehicle safely.
Unlike alcohol-related DUI cases, prosecutors cannot simply point to a blood alcohol concentration and argue that impairment is presumed. Instead, they must build a case using multiple pieces of evidence.
Why Marijuana DUI Cases Are Different From Alcohol DUI Cases
Alcohol DUI investigations benefit from decades of research and established legal thresholds. A breath test showing a blood alcohol concentration of .08 or higher creates a straightforward framework for prosecutors.
Marijuana cases are different.
THC can remain detectable in the body long after the effects have worn off. As a result, a positive test does not necessarily prove a driver was impaired at the time of a traffic stop.
This creates one of the central challenges in marijuana DUI cases: proving the difference between prior use and actual impairment.
How Police Look for Signs of Marijuana Impairment
Most marijuana DUI investigations begin with a traffic stop. During the encounter, officers look for indicators they associate with cannabis use. These observations may include:
- Odor of marijuana
- Red or bloodshot eyes
- Delayed responses
- Difficulty following instructions
- Alleged problems with coordination
Officers often document these observations in reports that later become part of the prosecution’s case.
However, many of these observations can have alternative explanations, including fatigue, allergies, stress, or medical conditions.
What Are Field Sobriety Tests Used For?
Field sobriety tests are one of the primary tools officers use when investigating suspected marijuana impairment. Common tests include:
- Walk-and-turn
- One-leg stand
- Horizontal gaze nystagmus
These tests were originally developed for alcohol investigations and are frequently criticized when used to assess drug impairment.
Roadside conditions, injuries, medical issues, age, anxiety, and physical limitations can all affect performance. In Annapolis DUI cases, defense attorneys often examine whether poor performance actually demonstrates impairment or something entirely unrelated.
What Is a Drug Recognition Expert (DRE)?
In some cases, officers request assistance from a Drug Recognition Expert, commonly called a DRE.
A DRE receives specialized training intended to identify signs of impairment caused by different categories of drugs. The evaluation may include:
- Eye examinations
- Balance assessments
- Vital sign measurements
- Observations of behavior and appearance
Although prosecutors frequently rely on DRE testimony, the conclusions remain opinions rather than direct measurements of impairment.
The reliability of these evaluations is often a significant issue in court.
How Blood Testing Is Used in Marijuana DUI Cases
When police suspect marijuana impairment, they may seek a blood sample.
Blood testing can identify the presence of THC or its metabolites. However, unlike alcohol testing, a positive THC result does not automatically establish that a person was impaired while driving.
This is because THC may remain detectable after the impairing effects have ended. As a result, prosecutors often combine blood test evidence with officer observations, field sobriety tests, and DRE findings to prove impairment.
How Hartman Attorneys at Law Approaches Marijuana DUI Cases
Marijuana DUI cases require a detailed review of how the investigation was conducted and how impairment was allegedly established.
At Hartman Attorneys at Law, we examine the evidence from every angle, including the traffic stop, officer observations, field sobriety testing, DRE evaluations, and laboratory results. Our goal is to determine whether the State can actually prove impairment rather than simply prove marijuana use.
When the evidence does not support the allegations, we work to challenge the assumptions underlying the prosecution’s case. If you have been charged with a marijuana DUI in Annapolis or anywhere in Maryland, connect with us today.