When police pull over a vehicle and arrest the driver for driving while impaired, the investigation into those charges likely began before the driver stopped. In fact, it is likely that police had their suspicions that the driver had been drinking before they decided to stop the vehicle. Those suspicions and the reason for pulling a driver over will likely be an important element in the driver’s DWI defense.

Aside from sobriety checkpoints, police must have reasonable suspicion that a driver is impaired before making the driver stop. In other words, police may not pull a driver over just to check whether there is alcohol on his or her breath. Usually, officers report observing certain signs that a driver is not in control of the vehicle, such as swerving, riding the center line or braking for no reason. Often, the traffic stop is initially based on an observed traffic infraction, such as an improper lane change.

If police arrive on the scene of an accident, however, they may ask the drivers of the involved vehicles to submit to roadside sobriety tests. An officer may also take this action if he or she pulls over a driver for another issue, such as a broken taillight, but observes signs that the driver may have been drinking. However, without a reasonable suspicion that the driver may be impaired, police may be violating the driver’s rights by pulling him or her over in the first place.

When police officers make an arrest following a traffic stop for which they had no reasonable suspicion, any evidence they collect may be eligible for exclusion if the case goes to court. This may include field sobriety tests and even the results of a blood alcohol test. Because of this, those facing these issues in Minnesota may benefit from the advice of an attorney for building a strong DWI defense.