For as common as traffic stops are, there is a lot of misinformation about what kinds of related action are legal and what kinds are not (for drivers as well as police officers). This is especially true of stops related to alleged drunk driving.

In today’s post, we’ll discuss an important aspect of DUI defense: The initial justification for the stop. Although a police officer can pull you over for a variety of reasons, he or she must be able to demonstrate that the stop was based on a “reasonable suspicion” of criminal activity or some other legal violation.

What is reasonable suspicion?

Most Americans are not terribly familiar with the legal term reasonable suspicion. It is similar in nature to the better-known term “probable cause.” The difference between the two is essentially a matter of degree. In order for an officer to briefly detain someone (including pulling them over), he or she must have a reasonable suspicion that the person may have committed a crime or otherwise violated the law.

Probable cause is a higher standard. The officer must believe, based on the evidence available, that the person probably committed a crime.

A traffic stop can be initiated based on reasonable suspicion. In order for an arrest to be made, however, the officer must gather enough evidence to establish probable cause of DUI or some other crime.

Traffic stops do not need to be based on suspicion of DUI

An officer may pull you over if he or she observes erratic driving that could indicate intoxication. This could include swerving, frequent braking, driving too fast or too slow and almost hitting other cars or pedestrians.

That being said, the officer does not need to suspect drunk driving when he or she first makes the stop. Instead, the stop may be based on an observed traffic violation (failing to signal a turn) or problem with your vehicle (a burned-out headlight, for example).

If you have been charged with DUI, you may have more defense options than you realize. Challenging the justification of the traffic stop is just one factor to explore. To better understand your options, please speak to an experienced criminal defense attorney.