California DUI Probable Cause

In a DUI investigation (as with any other criminal investigation), police officers must have probable cause during a vehicle stop, detainment or arrest. Probable cause simply means that a police officer must have reasonable belief that a person has committed a crime. Under California law, if police did not have probable cause to stop, detain or arrest a person, then any evidence the state collects against the person can be suppressed in court. If you have recently been arrested for DUI, please contact a DUI defense attorney. An experienced DUI lawyer will review the facts of your case to ensure that police followed proper protocol (including probable cause) during your DUI investigation.

Let’s say for example that police witnessed you speeding and stopped your vehicle. Committing a traffic violation such as speeding is grounds for police to stop your vehicle. However, when police walk up to your vehicle they cannot start questioning you about drinking and driving unless they have probable cause to believe you are DUI. For instance, if they see open alcohol containers or smell alcohol coming from your vehicle, this is probable cause to start a DUI investigation.

If police officers observe signs of drinking and driving, they have probable cause to detain you by asking you to take a breathalyzer or field sobriety test. After taking a breath test or field sobriety test, police officers have probable cause to arrest you for DUI if your blood alcohol content was over the state’s legal limit of .08% and you failed a field sobriety test. If you passed the tests, they do not have probable cause anymore to believe that you have been drinking and driving and cannot arrest you for DUI.

Once your DUI case makes it to court, the prosecution bears the burden of proving that probable cause existed during the stop, detainment and arrest. It is the job of your defense attorney to determine if police had probable cause during each stage of the investigation and to request that evidence such as your breath test and field sobriety test results be suppressed if probable cause did not exist.