When Can the Police Pull You Over in Iowa?
Police cannot stop a vehicle simply because an officer wants to investigate the driver. A traffic stop is a seizure under both the Fourth Amendment to the United States Constitution and article I, section 8 of the Iowa Constitution.
To lawfully stop a vehicle, police generally need an objectively reasonable basis for doing so. That may include an observed traffic violation or reasonable suspicion that criminal activity is occurring. In OWI investigations, officers frequently rely on alleged speeding, lane violations, equipment violations, erratic driving, or other driving behavior as the basis for a stop.
Not every driving mistake or minor movement within a lane, however, is enough to justify a traffic stop.
Evidence From an Illegal Traffic Stop May Be Suppressed
When police make a traffic stop without sufficient legal justification, evidence obtained as a result of that stop may be excluded from the case.
This is commonly referred to as the exclusionary rule. The purpose of a motion to suppress is to prevent the State from using evidence obtained through an unconstitutional seizure.
In an OWI case, that can be significant. Evidence developed after the stop may include the officer’s observations, statements by the driver, field sobriety testing, preliminary breath testing, chemical testing, and other evidence gathered during the investigation. If the initial stop was unlawful, the defense may seek suppression of evidence obtained as a result.
Traffic Stop Found Unlawful
Lucas Taylor represented a defendant in an Iowa OWI case in which a trooper stopped the defendant after observing what the officer described as weaving and contact with the fog line.
The officer originally relied on one Iowa traffic statute as justification for the stop, but later acknowledged that statute did not apply. The State then argued that a different traffic statute justified the stop.
The court reviewed the dash-camera video rather than relying solely on the officer’s description of the driving. The video showed only two minor contacts with the fog line, each lasting less than three seconds, and did not show substantial weaving or other significant driving problems.
The court concluded that the State had not established a lawful basis for the traffic stop. The motion to suppress was granted, and the evidence obtained after the stop was excluded.
The Video Can Matter More Than the Officer’s Description
Traffic-stop cases often turn on the specific facts shown by the evidence. An officer may describe a vehicle as weaving, crossing a line, or failing to maintain its lane, but dash-camera or body-camera video may provide a more complete picture of what actually occurred.
The legal question is not simply whether the vehicle moved within its lane or briefly touched a roadway line. The court must determine whether the officer had an objectively lawful basis to seize the driver at the time the stop was made.
Read the Court’s Ruling
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