What Happens During a DUI Investigation?

Posted by Robert Berglund | Jul 12, 2017 | 0 Comments

There are a number of ways that a law enforcement officer can come into lawful contact with a driver, including a traffic stop, following an accident, and at a DUI checkpoint.  Our previous blog post "What Leads To a DUI Investigation?" discussed this issue.  Let's assume that the initial encounter between the officer and the driver is legal (e.g., the officer pulled over the driver for an unsafe lane change or for speeding).  What happens if the officer believes that the driver may be impaired?  This is when a DUI investigation officially begins.  Usually the basis for the officer's belief is that the driver displayed "objective symptoms of intoxication."  The most common symptoms include bloodshot/watery eyes, odor of an alcoholic beverage, unsteady gait, and slurred speech.  If the officer observes any of these symptoms he will ask the driver to submit to a number of field sobriety tests, including a breathalyzer, or preliminary alcohol screening (PAS) test, to assist the officer in making the determination as to whether the driver is DUI.

DUI Investigation Before Arrest

As we wrote about on our DUI blog "Field Sobriety Tests During DUI Investigations," the officer will ask the driver to do a number of tests, including the horizontal gaze nystagmus (HGN), the Walk-and-Turn (WAT), and the One-Leg Stand (OLS).  These are the preferred field sobriety tests since they have been approved by the National Highway Traffic and Safety Administrations (NHTSA), and thus are referred to as "Standardized" Field Sobriety Tests.  The officer will also ask the driver to blow into the PAS device.  Note that the protocol just described assumes that the driver is under the influence of alcohol only.  If drug use is suspected the officer may contact a drug recognition evaluator (DRE) to examine the driver and conduct additional tests that are more specific to a person under the influence of drugs.  If the driver performs poorly, in the officer's opinion, on the field sobriety tests and/or blows a .08 or greater measurable amount of alcohol on the PAS, the person will be arrested for DUI.  It should be noted that participation in the requested field sobriety tests, including taking the PAS test, is voluntary unless the person is on probation for a previous DUI.  A driver under 21 years of age must comply with a request to submit to the PAS test.  

DUI Investigation After Arrest

The investigation is not completed once the handcuffs are on.  Following an arrest for DUI, California law requires the person to then submit to either a breath or a blood test or face additional penalties, including a one, two, or three year driver's license suspension (depending on whether the driver has any prior DUI convictions), additional fine, and mandatory imprisonment.  This is mandated by California's implied consent law.  (Although the legality of criminally penalizing a person who refuses to take a blood test without obtaining a warrant is in doubt following the United States Supreme Court decision in the Birchfield v. North Dakota case).  If the person does not agree to submit to a breath or blood test, officers will report this as a "refusal" and the DMV will suspend their driver's license for at least one year.   If the person complies with the request, the breath or blood test results will be used against them in court if DUI charges are filed.  In other words, these post-arrest breath and blood tests are part of a further DUI investigation, which are allowed under California law, and serve as more evidence that will be used against a person who is arrested for DUI.

Contact Berglund Law Office, P.C. Following DUI Arrest

We specialize in defending persons arrested on suspicion of DUI.  Los Angeles DUI Lawyer Robert D. Berglund will personally return your phone call or email.  CONTACT us today for a free and confidential consultation. 

About the Author

Robert Berglund

Attorney Robert D. Berglund specializes in representing persons arrested on suspicion of Driving Under the Influence of alcohol or marijuana...


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