Police officers do not have free reign during traffic stops

As you may know, the the U.S. Constitution provides protection against unreasonable searches and seizures. Like many people, however, you may be a little uncertain about what that really means. Learning more about this area of your constitutional rights can help you protect yourself in the event that you are pulled over and suspected of driving under the influence.

The Fourth Amendment to the U.S. Constitution prohibits unreasonable searches and seizures by government officials. This means that the police and other government workers cannot detain you or invade your privacy arbitrarily; they must have a reasonable justification for doing so. The justification required depends on the circumstances. The more intrusive the search or seizure, the bigger the justification needed to justify it.

Not every police interaction requires probable cause

One level of justification that you have probably heard of is called probable cause. This is the level of justification that police usually need to put someone under arrest or obtain a search warrant. Because both of those examples are considered major intrusions on a person's individual rights, they require a high level of justification.

Probable cause means that the facts and circumstances known to the officer at the time would lead a person of ordinary caution to believe a crime has been committed or is being committed by the individual arrested. In the context of a traffic stop, probable cause for a DUI arrest may be supplied by the driver smelling of alcohol, slurring his or her speech and failing a field sobriety test. Probable cause must be based on actual evidence and cannot be based on a hunch, racial bias or gut feeling.

A lower standard for traffic stops

Although probable cause is required for police to conduct an arrest, it is not required for smaller police interactions like routine traffic stops. In most cases, because a traffic stop is considered a relatively minor intrusion on a person's rights, it requires a lower level of justification, which is known as "reasonable suspicion." In California, an exception exists for sobriety checkpoints, which can be conducted without reasonable suspicion.

Reasonable suspicion means that the officer must have a reasonable belief that illegal activity has taken place. Again, this must be based on actual, specific evidence. In terms of a traffic stop, this can be supplied by something as simple as a broken taillight or failing to signal a turn. This is why it is possible to end up arrested for DUI even while driving normally; once police have legally stopped someone for unrelated reasons, they might obtain other evidence that that justifies alcohol testing or making a DUI arrest. For example, this may happen when a driver stopped for other reasons slurs his or her speech, has an open container visible in the vehicle or admits to having consumed alcohol.

Field sobriety testing helps establish probable cause

Another way that police officers can gather evidence to establish probable cause to make a DUI arrest is through field sobriety testing, which involves performing tasks like walking in a straight line, touching your nose or reciting the alphabet. If you are charged with DUI, one of the ways that an attorney can help is by reviewing your case and identifying possible issues occurring during the traffic stop, arrest and testing. If there are issues with the way the police conducted any of those processes, they may result in dismissal or assist in negotiating lesser charges or penalties.