Probable Cause in a DUI Stop in Maryland

The actual standard for an officer to pull somebody over is reasonable, articulable suspicion that a traffic offense or a crime is in the process of occurring or has occurred. It’s not quite the same as probable cause. Probable cause is actually a little bit higher of a standard than reasonable, articulable suspicion. The officer has to have a reasonable belief and then be able to articulate that reasonable belief that a traffic offense occurred. That offense doesn’t have to be DUI in order to initiate a DUI stop, so the officer could have reasonable, articulable suspicion of speeding, for example. Once they’ve initiated the stop, then they can further the investigation, pursue a DUI arrest, or even search the vehicle if there is probable cause.

What Does Probable Cause Mean?

Probable cause is a higher standard than reasonable, articulable suspicion. Probable cause is more than a reasonable belief, but less than proof beyond moral certainty. In order to arrest somebody for suspicion of DUI rather than just stop them for a traffic offense, an officer needs to have probable cause. For example, if an officer sees a car weaving all over the roadway, they may have reasonable, articulable suspicion of DUI and reasonable, articulable suspicion of failure to drive on the right half of the roadway, failure to obey a traffic control device, or some reason to initiate the stop. Once they’ve made the stop, talked to the driver, smelled alcohol, and conducted field sobriety tests, an officer can form probable cause.

Common Reasons Used By Officers to Pull Over Potentially Impaired Drivers

A major reason would be weaving through traffic, which in Maryland they write as failure to obey a traffic control device. In that case, the lane markers on the highway constitute the traffic control device that the driver fails to obey. Other big ones are speeding, driving too slowly, and driving without headlights. People will often leave a well-lit parking lot at one or two o’clock in the morning and fail to turn on their headlights. Other reasons are equipment violations, such as a broken tail light or brake light, and any of the merited traffic offenses like failure to signal.

What Is Reasonable, Articulable Suspicion?

The suspicion has to be reasonable and it has to be articulable. Reasonable suspicion means the officer has to have some kind of basis in reason. For example, if the person is speeding, the officer can’t simply say “He passed me.” They have to say something along the lines of, “He passed me, so I hit him with my radar gun. The radar gun said he was traveling 88 mph in a 65 mph zone,” or “I’ve been trained to estimate speeds using visual estimation and I visually estimated their speed to be 88 in a 65.”

Articulable suspicion means the officer has to be able to explain it to the court. The officer can’t simply say, “I had a gut feeling that they were speeding.” The officer has to be able to articulate it. That is a lower standard than probable cause. This all ties back to a Supreme Court case, Terry v. Ohio, that basically said that officers don’t need probable cause to effectuate a traffic stop because it’s a “de minimis” invasion of personal privacy, because it’s a brief detention. The officer only needs reasonable, articulable suspicion.