Understanding Probable Cause & DUI

According to the law, a police officer cannot conduct a traffic stop, DUI investigation, or DUI arrest without probable cause. In other words, a law enforcement officer cannot stop your car unless he/she has reasonable evidence indicating that you committed a crime. Probable cause is upheld by the Fourth Amendment of the United States Constitution, which disallows police officers from making "unreasonable searches & seizures."

Probable cause applies to traffic stops, detainments, DUI investigations, and arrests. However, this doesn't mean that for the initial traffic stop must involve drunk driving; in fact, many DUI arrests are the result of other violations, such as speeding, red lights, and fix-it tickets.

Before an officer can initiate a DUI investigation, he/she must have some evidence that the motorist is under the influence of alcohol or drugs– even if the original traffic stop didn't involve DUI. As law enforcement progresses through each phase of the DUI process (traffic stop, investigation, and arrest), the officer must uncover additional reasons to believe that the driver is intoxicated. While a simple infraction, such as excessive lane changes, could merit a traffic stop, it may not warrant a DUI investigation.

During a DUI investigation, the officer might ask you repeated questions about your alcohol consumption; ask you to perform field sobriety tests; and request that you submit to a breathalyzer test. The officer cannot execute this investigation without evidence of DUI. Common probable causes include the following scenarios:

  • The law enforcement officer smells alcohol on your breath.
  • The officer notices an open container of alcohol in your vehicle.
  • The officer notices that your eyes are watery and your face is flushed.
  • Law enforcement believes that you exhibit any sign of intoxication.

If law enforcement initiates an investigation without reasonable suspicion for DUI, any evidence collected during the investigation may be inadmissible in court. When a judge decides that evidence is "inadmissible," prosecutors cannot use it against you in court.

After an investigation, law enforcement officers cannot arrest your for driving under the influence without further evidence of DUI. The officer must be able to articulate exactly why he/she believed that you were intoxicated. For instance, an officer might not have probable cause to make an arrest if you passed field sobriety testing. The officer cannot make an arrest simply because he/she suspected that you were drunk; the officer must explain the facts that led him/her to believe that you drove under the influence.

What happens if you were arrested in California without reasonable suspicion?

If you suspect that law enforcement did not have a reason to make a DUI arrest, your attorney can file a motion to suppress any evidence held against you. Evidence obtained through a wrongful arrest cannot legally be used in court. This motion is one of the most common motions filed by DUI attorneys in California.

After filing, the court will initiate a suppression hearing (also called a 1538.5 Suppression Hearing), where your DUI defense attorney has the opportunity to demonstrate that the officer made a wrongful arrest. If the court determines that the arrest was a violation of your Constitutional rights, the court may decide to suppress certain evidence related to your case. Your attorney may file a motion if:

  • Law enforcement stopped your car, even though you didn't commit a traffic violation.
  • Law enforcement detained you, even though you failed to demonstrate signs of DUI.
  • Law enforcement arrested you, even though you were not under the influence of alcohol.

Depending on the circumstances surrounding your case, law enforcement may be able challenge all of the evidence that the prosecution planned to use against you.

Arrested without probable cause? Contact our Ventura DUI lawyers!

If you were wrongfully arrested for drunk driving, our Ventura DUI lawyers can help you file a suppression hearing. We have served clients with passion, integrity, and skill for more than 50 combined years. Today, we offer DUI defendants in Ventura the opportunity to stand up for their rights in court and combat unfair accusations. We have served on more than 200 jury trials and are deeply familiar with the California DUI process. Contact us today to see what Lessem, Newstat & Tooson, LLP can do for your case. When it comes to DUI defense, there is no substitute for professional, legal experience. That's why you need a DUI defense attorney in Ventura who you can trust. Call our office for more information and a free case evaluation.