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What you need to know about DUI law: The Traffic Stop

It’s late at night. You’re driving home from a friend’s house after having a few drinks. And those dreaded red lights flip on behind you.  As you pull over to the side of the road, you hope the police car will swerve around you, off to stop a real “bad guy.” But instead of passing you, the car pulls to a stop behind you.  So what do you need to know?

Anywhere in the United States, under the Fourth Amendment, law enforcement officers need probable cause to stop you.  This probable cause can be anything that would lead a reasonable person to believe that you, as the driver, has committed a crime.  While some people think that the officer needs to have seen you swerve, run through a stop sign or stop light, or hit an object, the truth is that even simple traffic infractions such as speeding, having a taillight out, not having a front license plate, or failing to wear your seatbelt are enough.

Once stopped, the officer is free to approach you and your car to investigate.  One of the telltale signs a driver has been drinking, and one of the first observations an officer usually makes in DUI cases, is that an odor of alcohol permeates the car.  Should an officer smell alcohol, you can bet he’s going to start asking questions to see if he’s just pulled over another DUI driver.  It’s at this point when even benign facts start working against you.  While you may rightfully claim that you smell like alcohol because you did drink earlier, or that a friend spilled a drink on you, the officer will worry it’s because the smell is emanating from your breath ad you’re still intoxicated to the level you might be impaired.  While you may rightfully claim that your eyes are bloodshot because you’re tired, the officer is worried that you have so much alcohol in your system that the alcohol is causing small blood vessels in your eye to become dilated and inflamed.   While you may rightfully claim that you’re having trouble communicating clearly is because English is not your native language, the officer is worried you’re so intoxicated your speech is slurred.

Chances are, the next thing the officer is going to do is start asking you questions.  It’s important to keep in mind that you have the right to remain silent. As defense attorneys, we cannot underscore this enough.  But should you feel compelled to speak with the officer, keep in mind that anything you say can and will be used against you.  Some of the routine questions are these:

  • Have you been drinking tonight?
  • When did you have your last drink?
  • When did you last sleep?
  • Are you on any medications right now?

If, after asking you these questions, whether you answered or not, the officer still believes you may have been driving under the influence, you’re going to be asked to take a series of field sobriety tests (FSTs).  Most of the FSTs are designed to test your ability to multitask at a very basic level.  You’re asked to perform a mental activity—such as counting—with a physical activity—such as maintaining your balance. Another test you’ll almost certainly be given is the “horizontal gaze nystagmus” test, in which the officer will ask you to follow an object—typically his pen—with your eyes while keeping your head still.  What he’s looking for is whether, and where, your eyes begin to involuntarily jerk.  This jerking, called nystagmus, is an involuntary reaction that occurs when alcohol depresses the central nervous system. If this jerking begins before the gaze reaches approximately a 45-degree angle-from-center, it indicates a possible blood alcohol content level over .05%.

The last of the FSTs is the breathalyzer test, in which the officer asks you to blow into a device, which measures the alcohol content from the air deep within your lungs.  It is important to note that YOU DO NOT HAVE TO CONSENT TO THESE FIELD SOBRIETY TESTS.

If the officer believes that he has probable cause that you were, in fact, driving under the influence, he can place you under arrest.

Post arrest, the officer will ask you to take another chemical test. This time, you ARE REQUIRED to provide a sample: either blood or breath.  Why are you required to give a sample this time? Because at the time you received your driver’s license, one of the terms of that license was that you would consent should an officer have probable cause to believe you were driving under the influence. Further, Penal Code 23612 states “A person who drives a motor vehicle is deemed to have given his or her consent to chemical testing of his or her blood or breath for the purpose of determining the alcoholic content of his or her blood, if lawfully arrested for [a DUI] offense.”

The results of those tests usually dictate whether you become involved in a battle on two fronts: the DMV and the Criminal Justice System.

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