When Can an Officer Make a DUI Arrest

Police are always on the alert for criminal activity. They are trained to notice suspicious behavior and to investigate within the boundaries of the law. For example, the driver of any car at any given moment may be under the influence of drugs or alcohol, but an officer cannot pull a vehicle over unless he or she has a reasonable suspicion that the driver is impaired.

If a police officer pulls you over and arrests you for drunk driving, you may have many questions and concerns about what will happen next. However, your attorney may be more interested in what happened before, particularly the moments leading up to the officer's decision to stop your vehicle.

Signs of impairment

Unless you happen upon a DUI checkpoint, which are illegal in Wisconsin, a police officer cannot pull you over until he or she has a reasonable suspicion that you are involved in a crime, such as driving while intoxicated. Experience and training teach law enforcement officers to look for signs that a driver may be impaired. If you display any of these behaviors or others, it may prompt an officer to pull you over:

  • Drifting across the center line
  • Driving in the middle of the road
  • Swerving
  • Driving too slowly or at inconsistent speeds
  • Making an illegal turn
  • Hitting the brakes frequently or stopping for no reason
  • Narrowly missing parked cars or other objects on the side of the road

These and other erratic actions indicate to police that something may be wrong with the driver and gives an officer reasonable suspicion to make the stop.

Probable cause is another issue altogether

Suspicion is not enough for police to make an arrest. If, after your traffic stop, the officer places you under arrest, it must be because he or she now has evidence that you are impaired behind the wheel. This evidence, called¬†probable cause, can include the results of a field sobriety test — which you can refuse to take — or from other observations, such as the smell of alcohol on your breath, your slurred words or the presence of an open container in plain sight in your car.

Most often, the defining cause for your arrest will be a breath test. If your blood alcohol registers .08 on a properly administered and calibrated breath test, the officer can conclude that you are likely impaired and place you under arrest. At this point, you would benefit from legal counsel, who will examine the officer's procedures from the first moment to determine if police violated your rights in any way.