Pennsylvania’s medical marijuana program gives eligible patients the ability to legally use cannabis for certain health conditions, but it does not give anyone the right to drive while impaired. In fact, under Pennsylvania law, you can still be charged with DUI even if you have a valid medical marijuana card and even if you are not actively impaired at the time of the stop.
These cases are complex, and many people do not realize how easily a routine traffic stop can escalate into a marijuana-related DUI investigation. It is a good idea to hire a Pennsylvania DUI lawyer to protect yourself. If you are facing a medical marijuana DUI—or you believe you may be under investigation—contact McKenzie Law Firm, P.C., today for a free consultation to understand your options.
We do everything possible to protect our clients from the moment they hire us to the moment their case is completed. Here are just a few of the benefits our firm offers that others cannot match:
McKenzie Law Firm, P.C., is led by attorney David McKenzie, a former criminal prosecutor who uses his insider knowledge to anticipate how the Commonwealth builds DUI cases. He understands the weaknesses in marijuana-related evidence, the limitations of THC testing, and the investigative shortcuts officers often take. This gives clients a strategic advantage from day one.
From the moment a client retains our firm, they get direct access to David by email, text, phone, or social media. We answer calls 24/7 and provide frequent updates so clients never feel left in the dark. This level of communication helps people navigate the stress of a criminal case with confidence and clarity.
Our law firm’s motto—“We Measure Our Success By Your Success.”—reflects our commitment to helping clients avoid jail time, keep their driver’s licenses, and prevent a DUI conviction from damaging their future. We work relentlessly to reduce or dismiss charges whenever possible.
With McKenzie Law Firm, P.C., clients never face surprise legal fees. We will tell you what our fee is and not deviate from that amount, no matter how long your case takes.
Our firm has earned a 10/10 AVVO rating, a 5-star Google rating, and the “10 Best Award in Client Satisfaction” from the American Institute of DUI/DWI Attorneys—recognition that speaks to our dedication and track record.
McKenzie Law Firm, P.C., represents individuals facing medical marijuana DUI charges in Montgomery County, Chester County, Bucks County, and Delaware County. Local familiarity with prosecutors, judges, and court procedures helps us build strategic, effective defenses tailored to each jurisdiction.
With these kinds of cases, there are many factors to consider that do not play a role in alcohol-related DUI cases. Our marijuana DUI lawyer can explain all of these to you, including:
Pennsylvania treats marijuana differently from alcohol. Instead of requiring proof of impairment, state law allows the police to charge a driver with DUI if chemical testing reveals any amount of certain marijuana metabolites in their system. Because THC can linger long after any intoxicating effects have worn off, people who legally use medical marijuana may still face DUI charges even when they feel completely sober.
Penalties may vary depending on the nature of the alleged offense and the statutes that apply, so it is best to work with a lawyer who understands the nuances of these cases.
A medical marijuana card authorizes use of the drug, not impaired driving. Many people assume their card gives them some level of protection, but it does not. Officers and prosecutors can pursue DUI charges regardless of whether someone is a registered patient.
It is important to be aware of the risks involved in driving with a medical marijuana card:
A medical marijuana DUI often begins as a simple traffic stop for speeding, a broken taillight, or another minor issue. Officers may escalate the stop if they notice the smell of marijuana, bloodshot eyes, inconsistent statements, or nervous behavior. Routine questions about whether the driver has been drinking often evolve into inquiries about marijuana use.
Many drivers accidentally reveal their medical marijuana card while reaching for their identification. This is a serious mistake.
Officers know that marijuana can stay in the body for up to 30 days. The moment they see the card, they may immediately assume recent use and begin pursuing a DUI investigation, even without signs of impairment. They may ask additional questions, request field sobriety tests, or seek consent for a blood draw.
For this reason, always keep your license, registration, and insurance separate and ready before the officer approaches. You must comply with lawful instructions, but you are not required to volunteer information about your medical marijuana status.
Even though Pennsylvania permits qualified patients to use medical marijuana, the state still relies on chemical testing to determine whether a driver has THC or marijuana metabolites in their system. Understanding how this testing works—and its shortcomings—can help you see why so many medical marijuana users face unfair DUI charges.
Unlike alcohol cases, where officers can use breath tests, marijuana DUIs in Pennsylvania rely almost entirely on blood testing. After a DUI arrest, officers typically request a blood draw to look for:
Because metabolites can linger for days or even weeks, registered medical marijuana patients often test positive even when they have not used cannabis recently.
Many people do not realize that metabolite presence does not prove impairment. Active THC may indicate recent use, but metabolites only show that marijuana was used at some point in the past. Pennsylvania law still allows prosecutors to pursue charges based solely on these lingering substances.
Blood draws often occur hours after the initial traffic stop. During that time:
These issues may create opportunities for McKenzie Law Firm, P.C., to build a strong defense.
Unlike alcohol, THC levels do not correlate reliably with impairment. Someone may test positive long after they are sober, while another person may appear impaired with relatively low THC levels. The science is far from settled, which is why knowledgeable legal representation is so important.
If you believe flawed testing contributed to your DUI arrest, McKenzie Law Firm, P.C., can review the evidence and determine whether the chemical results can be challenged. Call now to begin.
While being charged with a crime can be frightening, you should know that no outcome is inevitable, especially when it comes to marijuana DUI cases:
Police commonly rely on standardized sobriety tests originally developed to detect alcohol impairment. These tests are not validated for marijuana use, and officers may misinterpret normal medical symptoms, fatigue, or anxiety as signs of impairment.
DRE officers attempt to identify impairment through physical signs like pupil size or heart rate. These indicators are subjective and can be influenced by factors unrelated to marijuana, such as medical conditions, stress, or prescription medications.
These weaknesses often provide fertile ground for a strong defense.
The penalties you face may depend on a variety of factors, including:
They also depend on if this is your first offense or not.
A first medical marijuana DUI is still treated seriously. Depending on the circumstances, drivers may face license suspension, probation or possible jail time, mandatory treatment, and ignition interlock requirements.
Repeated marijuana DUI allegations can lead to significantly harsher consequences, including longer suspensions, mandatory jail time, and higher treatment requirements. Again, penalties vary widely and depend on how the prosecutor charges the case.
A marijuana DUI can affect insurance premiums, employment opportunities, professional licenses, and even college admissions or financial aid. These collateral consequences often make it even more important to fight the charges aggressively. We encourage you to get in touch with our criminal defense attorney right away to protect yourself.
McKenzie Law Firm, P.C., can decide on the right defense strategy for you based on your situation. Common approaches include:
The first question is often whether the officer had valid reasonable suspicion to initiate the stop. If not, any evidence gathered afterward may be suppressed.
Officers may over-rely on assumptions or misunderstand normal behavior. A lawyer can challenge whether there was legitimate evidence suggesting impairment at the time of arrest.
THC testing is far from perfect. Delays in testing, issues with the blood draw process, or mishandling of samples can undermine the results. Additionally, because THC metabolites do not correlate reliably with impairment, a lawyer can argue that positive results alone are insufficient to prove intoxication.
If the police questioned the driver without proper Miranda warnings or conducted an unlawful search, the defense may seek to suppress those statements or evidence.
A lawyer may show that any signs the officer interpreted as impairment—such as anxiety, medical symptoms, or minor driving issues—were unrelated to cannabis use.
Your first steps should include the following:
It is critical to act right away after an arrest because of:
Pennsylvania’s medical marijuana laws are complicated, and even registered cardholders can face DUI charges without being impaired. The consequences can be serious, but strong defenses exist—especially when the police rely on assumptions or flawed testing to support an arrest.
If you are facing a medical marijuana DUI or believe you may be under investigation, McKenzie Law Firm, P.C., is ready to help. Our personalized approach, accessibility, and prosecutorial insight allow clients to move forward with confidence.
Contact us today for a free consultation and learn how we can protect your rights.
