What Gives Police Probable Cause to Make a DUI Arrest in Maryland?

 Posted on September 26, 2026 in DUI

Probable cause for a DUI arrest in Maryland is built from a combination of observations, not one single fact. An officer needs enough specific details to reasonably believe a driver was operating a vehicle while impaired. Those details usually come from how the car was moving, what the officer noticed at the window, and how the driver performed on roadside tests. 

If you were arrested for DUI in 2026, our Montgomery County DUI defense lawyers can review whether the officer actually had probable cause.

What Do Police Look for During a Maryland DUI Stop?

Officers build a DUI case in stages, starting with the driving itself, then the conversation at the window, then any roadside testing. The observations that show up most often in reports include:

• Weaving, drifting across lane lines, wide turns, or driving without headlights

• An odor of alcohol coming from the vehicle or the driver

• Bloodshot or glassy eyes, flushed face, or slurred speech

• Fumbling while reaching for a license or registration

• Admitting to having a drink, even one

• Open containers, or the smell of cannabis inside the car

• Trouble following simple instructions or answering basic questions

Keep in mind that there are two different standards in play for a DUI case. Pulling you over only requires reasonable suspicion, meaning specific facts pointing to a possible violation like speeding or a broken taillight. Arresting you requires probable cause, a higher bar that asks whether the observations, taken together, actually add up to impairment.

Do Field Sobriety Tests Create Probable Cause in Maryland?

Field sobriety tests are one of the tools officers may use to decide whether there is probable cause for a DUI arrest. Three standardized field sobriety tests are commonly used. These are the horizontal gaze nystagmus test (which tracks eye movement), the walk-and-turn test, and the one-leg stand test.

These tests are not covered by Maryland's implied consent law, so refusing them does not trigger the license penalties that can follow refusal of a chemical breath or blood test.

The Roadside Breath Test Is Different From the Station Test

Under Maryland Transportation Article § 16-205.2, an officer who reasonably suspects impaired driving can ask you to take a roadside breath test before making an arrest. The statute says the result is a guide for the officer in deciding whether to arrest, and the state may not use it as evidence in court, though a defendant may. Refusing this roadside test is not a refusal under the implied consent law. The breath test given later at the station is the one that carries license consequences and can be used against you.

Can a Maryland DUI Charge Be Dropped if the Officer Lacked Probable Cause?

A DUI charge can be dismissed or significantly weakened when probable cause was missing. This is because evidence gathered after an unlawful arrest can be suppressed. Without the breath result and the officer's post-arrest observations, many cases cannot go forward.

Video evidence can be especially important when it contradicts the officer's report. Body camera or dash footage may show steadier walking, clearer speech, or problems with how roadside tests were explained or administered.

Field sobriety test results can also be challenged when outside conditions affect a driver’s performance. Roadside conditions can affect how someone performs on field sobriety tests, for example. A sloped or uneven surface, bad weather, nearby traffic, certain shoes, injuries, balance problems, or age can make it harder to complete the tests as instructed.

What Happens to Your License After a Maryland DUI Arrest?

A Maryland DUI arrest can create two separate proceedings. One is the criminal case. The other is an administrative action involving your driver's license through the MVA. You have 30 days from the Order of Suspension to request an administrative hearing. Requesting the hearing within 10 days can prevent the suspension from taking effect before the hearing. 

Schedule a Free Consultation With Our Silver Spring, MD DUI Defense Attorneys

At The Law Offices of Gerstenfield & Demirji, PC., we handle DUI cases with warmth and compassion. We have built solid working relationships with prosecutors across the county, which often opens the door for our clients to resolving a case without a trial. When a case calls for a fight instead, we are prepared to be aggressive about it.

Contact The Law Offices of Gerstenfield & Demirji, PC. at 301-589-9500 to talk to our Montgomery County DUI defense lawyers today. We’re available 24/7.

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