DUI/DWI and Unlawful Police Stops

DUIDWI and Unlawful Police StopsDriving under the influence (DUI) and driving while impaired (DWI) arrests typically result from a traffic stop by police. However, a police officer can’t pull you over without a valid reason. If an officer does not have a reason to pull you over in the first place, this can be the basis of a defense in a DUI case.


The Fourth Amendment to the Constitution prohibits unreasonable governmental searches and seizures. To perform a valid traffic stop, a police officer must have probable cause to believe that the driver has committed a traffic violation or a reasonable, articulable suspicion that the driver is violating either criminal or traffic laws. Without at least a reasonable, articulable suspicion, the traffic stop is illegal, and any arrest arising out of the stop is unlawful.

Reasonable articulable suspicion is less than probable cause. So even if the police officer doesn’t have probable cause to believe that a traffic violation has occurred, they may have a reasonable articulable suspicion that someone is driving while impaired by alcohol. Police officers have been trained to observe the driver before pulling them over.


Police officers base most traffic stops on the observation that a driver has committed a traffic violation. Sometimes the driving behavior gives an officer reasonable articulable suspicion that someone is driving impaired by alcohol. Common reasons for stops include:

  • Speeding: police officers are trained to pull over drivers if they are driving 10 mph over the speed limit or 10 mph under the speed limit. Driving under the speed limit may make an officer believe that you are driving under the influence.
  • Crossing Over the Yellow Line: Even if a driver crosses over the yellow line for only a moment, it is a ticketable offense, and the police officer has a valid reason for pulling you over.
  • Unsafe Lane Change: It can be difficult for the state to prove this charge as it is based on an officer’s subjective opinion on what is unsafe unless an accident occurred.
  • Weaving on the Road: It is not illegal to change lanes and to do so quickly if you are doing it safely and with your blinker on. But an officer may interpret your actions as weaving on the road.
  • Broken Equipment: Police officers commonly pull over suspected drunk drivers for broken tail lights, brake lights or license plate lights.

If you’ve been arrested for a DUI or DWI, it’s essential to make sure you have an attorney who is very experienced in Maryland DUI/DWI law to help you get the best outcome in your case. Contact us at Alpert Schreyer, LLC or call us at (301) 494-9620.

Leave a Reply