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How do reasonable suspicion and probable cause impact DUI stops?

On Behalf of | Aug 3, 2023 | DUI |

When someone is arrested on allegations of impaired driving, their situation often starts with a traffic stop. There are certainly exceptions to this generally approach, such as if someone has been involved in a car accident or if they’re in a state that allows for sobriety checkpoints. But the majority of drunk driving arrests start with a traffic stop.

There are two important legal elements to consider during a traffic stop. These are reasonable suspicion and probable cause. They are similar, but they are definitely different, and things have to be done in the right order by the police for any action that they take after the initial stop to hold up in court.

Reasonable suspicion

Reasonable suspicion is what gives the officer the ability to pull over a car in the first place. An officer either notices a traffic mistake or believes that a driver may be impaired. That officer may see them do things like:

  • Hitting the brakes too frequently
  • Driving very slowly
  • Driving erratically
  • Nearly getting into accidents
  • Making illegal turns and other maneuvers
  • Drifting between the lanes

This is known as reasonable suspicion because it’s not yet enough to make an arrest and the officer certainly doesn’t know that the driver is impaired. But the officer does know that the driver isn’t operating their car in a normal fashion, and so that allows them to make the stop.

Probable cause

The second part of the equation is probable cause, which is a higher standard than reasonable suspicion. It means that the officer has cause to believe that the driver is impaired. This often takes much more than just seeing that person make driving mistakes. For instance, an officer may administer a breath test or ask the driver to take field sobriety tests. If the driver fails these tests, then the officer may have probable cause to make an arrest. This is a step above the reasonable suspicion that allowed for the traffic stop in the first place.

Neither of these indicates a conviction is imminent

For those who have been arrested, it’s important to note that neither reasonable suspicion nor probable cause are enough for a conviction. They just allow for a traffic stop and an arrest, and they get the process of prosecution started. But a conviction is not guaranteed and drivers need to know that they do have legal options that may allow them to avoid criminal penalties associated with a stop and arrest.