Police officers in New York cannot just pull people over because they feel like it. Before a legal traffic stop can take place, an officer must reasonably suspect that the driver has committed a crime. Likewise, police cannot just arrest a person at a traffic stop unless they have probable cause to do so.

Reasonable suspicion as it applies to DWI

A police officer can only pull a suspected drunk driver over if the driver has done something to warrant the suspicion. Since the standard for reasonable suspicion is lower than it is for probable cause, a driver could potentially be pulled over for any minor traffic violation. Someone may also be pulled over for erratic behavior, like frequent braking, driving too close to the center lane or driving too slowly.

Reasonable suspicion allows a police officer to pull a driver over, but it is not enough to enable the officer to make an arrest. To arrest a driver for a suspected DWI, a police officer must first have probable cause.

What is probable cause for DWI?

The standard for probable cause is higher than the standard for reasonable suspicion. To have probable cause, the police officer must have evidence that the driver is probably drunk. A slight suspicion that a person may be guilty of DWI after seeing him or her swerve in his or her lane is not enough. Some examples of probable cause include:

  • A failed field sobriety test
  • A failed breath test
  • Physical signs of intoxication

Arrests with no reasonable suspicion or probable cause

If a police officer stops a vehicle without reasonable suspicion and then makes an arrest without probable cause, the DWI case may be dismissed. In situations like this, a criminal defense attorney may argue that the traffic stop was illegal. Sometimes, even if a defendant was intoxicated, an illegal traffic stop can render the whole case invalid.



James Auricchio was admitted to the practice of Law in 2001. He entered private practice in 2010 after earning distinction as a State and Federal Prosecutor.

Named to the list of Superlawyers, in 2020, 2021, 2022, 2023 and 2024, a distinction awarded to less than 5 percent of all attorneys in New York State