Proving that the police lacked probable cause for a DUI stop can be one of the most powerful defenses in a DUI case. If the stop was not legally justified, any evidence gathered after it, including breath test results, field sobriety tests, and the officer's observations, may be thrown out. Without that evidence, the prosecution's case can fall apart. If you are facing a DUI charge in 2026 and something about the stop did not feel right, Diamant Gerstein, LLC can help. Our Bethesda, MD DUI defense lawyers can assess what happened and find out whether your rights were violated.
To pull you over, an officer only needs reasonable suspicion. That is a lower bar than probable cause. It means the officer needs specific facts that suggest you may be breaking the law or committing a traffic violation. A swerve across a lane, a broken taillight, or running a red light can all give an officer enough reason to stop your car.
Once you are stopped, the officer needs to develop probable cause before they can arrest you for DUI. Under Maryland Transportation Article Section 21-902, it is illegal to drive while impaired by alcohol or drugs. To arrest under this statute, the officer has to be able to point to specific facts that give them a reasonable basis to believe you were doing exactly that. A general feeling that something seemed off is not enough. If they cannot point to enough specific evidence to meet that standard, the arrest is unlawful.
After pulling you over, officers look for signs of impairment. Common things they document include the smell of alcohol, bloodshot or watery eyes, slurred speech, trouble finding your license and registration, open containers in the vehicle, an admission of drinking, and poor performance on field sobriety tests.
None of these factors alone is necessarily enough. Officers usually need a combination of observations to justify an arrest. Your attorney will look closely at what the officer actually saw and whether it was truly enough to meet the legal standard for probable cause.
This is often the first line of defense in a DUI case. If the reason for the stop was not legally sufficient, the entire case may be in trouble. Your attorney will start by reviewing the police report and any video footage to find out exactly why the officer says they pulled you over.
Common ways to challenge the stop include showing that the driving behavior the officer described was not actually a traffic violation, that dashcam or bodycam footage contradicts the officer's account, that the stop was based on a hunch rather than specific facts, or that the officer used a minor reason to stop you when they had no real basis to suspect DUI.
In Maryland, a stop that violates your Fourth Amendment rights can be challenged through a motion to suppress. If the court agrees the stop was unlawful, the evidence from that stop cannot be used against you.
A motion to suppress is a legal request asking the court to throw out evidence that was gathered in violation of your rights. In a DUI case, this motion is most often used to challenge the stop or the way evidence was collected after the stop.
Your attorney files the motion before trial. At a hearing, the officer testifies about what they observed and why they pulled you over. Your attorney then cross-examines the officer and presents evidence showing the stop was not legally justified.
If the judge agrees your rights were violated, all evidence gathered as a result of the unlawful stop is thrown out. That usually includes breath or blood test results, field sobriety test performance, and any statements you made. In most DUI cases, losing that evidence leaves the prosecution with very little to work with.
Building a strong argument that the stop lacked legal justification requires gathering the right evidence quickly. Useful evidence includes:
Dashcam footage from the patrol car showing your driving before the stop
Bodycam footage of the officer's conduct during the stop
Traffic camera footage from the area where the stop happened
Your own dashcam footage if your vehicle had one
Statements from passengers or other drivers who saw what happened
The officer's written police report, which can be compared against video for inconsistencies
The officer's prior history of stops and any patterns of unlawful conduct
Inconsistencies between what an officer says in their report and what the video actually shows can be very powerful at a suppression hearing.
Our Bethesda, MD DUI defense lawyers are lifelong residents of Montgomery County with deep ties to this community. When you call, you’ll speak to them personally, because they believe every client deserves direct access to their attorney from day one. They are hands-on throughout the entire process and have been recognized on the Maryland Super Lawyers list. Contact Diamant Gerstein, LLC today at 301-560-2685 to schedule a consultation.
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