DUI: The Traffic Stop, The Investigation, The Arrest

The D.U.I. Roadside Investigation and Arrest

Attorney William B. Wynne represents those accused of Driving Under the Influence in the greater Tampa Bay area and surrounding counties. Dealing with Driving Under the Influence charges in Florida without a dedicated advocate in your corner, can be a daunting and overwhelming experience. A criminal attorney experienced in handling DUI cases, can bring you much needed peace of mind, and protect your rights. Contact us today for a free consultation.

DUI: The Initial Stop

Most DUI arrests occur during traffic stops on our roadways. Of course, this isn’t always the case. I’ve represented clients that were originally approached by police while sleeping in parked vehicles. I’ve even had clients that were nowhere near their vehicle at the time they were investigated for DUI and ultimately arrested. In fact, it’s not uncommon for the police to arrest a suspect long after they have (allegedly) exited their vehicle. This is a situation that plays out often when a car accident has occurred. Yet, despite these examples, the vast majority of DUI arrests occur during the course of simple traffic stops, which presents a unique set of circumstances and considerations for defense attorneys.

Often the police will look carefully for impaired driving patterns, late in the evenings or in the early morning hours. Police are clever and know when and where to look for impaired drivers. At the same time, DUI traffic stops take place during the day (at any time) and commonly occur after drivers are pulled over for speeding, having expired registrations, or malfunctioning taillights—to name just a few. Once a driver has been pulled over, if an officer suspects the driver may be impaired, and can articulate specific reasons for his suspicion, he can initiate a DUI investigation, regardless of the initial reason for the stop. At this point, the officer is required to inform the driver that a DUI investigation is being conducted. Tampa DUI attorney William B. Wynne can often raise legal challenges to the way the traffic stop was carried out. An improper stop can be challenged by a Motion to Suppress evidence.

Field Sobriety Exercises

According to the National Highway Traffic Safety Administration (NHTSA), Standard Field Sobriety Tests are defined as “a battery of three tests administered and evaluated in a standardized manner to obtain validated indicators of impairment and establish probable cause for arrest.”

These are the standard battery of tests administered by law enforcement and accepted as credible—generally speaking. A finger-to-nose test is also administered at times. These tests are used very often by law enforcement when attempting to determine if a person is operating a vehicle while under the influence of alcohol and/or drugs. These tests are meant to test a driver’s agility, coordination, and balance. And it is believed that an impaired driver will perform poorly on these tests. They are far from perfect, however. And it isn’t surprising to see a completely sober driver fail these tests. Or conversely, to see a very impaired driver (with a high tolerance) pass them. People with physical disabilities and limitations often struggle at these tests.

The DUI Stop and Arrest

The Horizontal Gaze Nystagmus Test

Typically, after the stop occurs and the officer claims to have reasonable suspicion of driver impairment, the first test administered is the Horizontal Gaze Nystagmus Test, often referred to as an HGN test. In a nutshell, the HGN test is done when the officer has a suspect track a stimulus he holds in front of their face (usually a pen or small light). As their eyes follow the stimulus, the officer checks their eyes for nystagmus, which is basically involuntary jerking or bouncing of the eyes. It is said that this jerking and bouncing of the eyes, is a sign of impairment.

Following this test, the DUI investigator will typically move the driver to a flat surface to perform the additional tests listed above. It is worth noting that whether a driver passes or fails these tests is completely up to the officer’s subjective discretion. Often (unfortunately) it seems that officers have already made up their mind on the issue, before the tests are even performed. Accordingly, most drivers would be better off not consenting to these tests. After all, the tests are voluntary.

It is worth noting that whether a driver passes or fails these tests is completely up to the officer’s subjective discretion.


The Formal DUI Arrest

Contrary to popular belief, the breath test is usually not administered in a DUI case until after the driver has already been arrested and taken back to the police station. It’s a bit of a backwards and counter-intuitive notion. After all, one would think the breath test should come before the arrest, since the decision to arrest would be based on the results of the test. Nevertheless, this is how it is done.

DUI investigators usually decide whether to arrest a driver based on everything they have observed up to the conclusion of the field sobriety exercises (without the breath test results). This means that they will consider several different factors. They will consider a suspect’s driving pattern and look for things like, weaving, swerving, wide turning, drifting, almost striking another vehicle or object, speeding, driving excessively slow, and many others. Upon making contact with the driver, law enforcement officers will observe and note cues like bloodshot watery eyes, slurred speech, fumbling fingers, difficulty answering questions, trouble maintaining balance, using objects to lean on, and difficulty exiting the vehicle. Police officers (particularly those trained as DUI investigators) are specifically trained to observe and interpret these indicators of impairment.

The Breath Test

Breath tests in Hillsborough County (and Florida generally) are administered on a machine known as the Intoxilyzer 8000. In Tampa, these tests are typically administered at the Orient Road Jail, after a suspect has already been arrested for DUI. Breath tests work by measuring the weight of alcohol in blood or breath. This is done in terms of grams of alcohol per 100 milliliters of blood, or grams of alcohol per 210 liters of breath. These machines work by using infrared spectrometry to detect whether alcohol is present. This presence is detected by measuring the amount of light absorbed by molecules in the breath at specific wavelengths. In Florida (and the rest of the country) a blood alcohol content of .08% is all that is needed to legally presume a driver was impaired.

Refusing to take the breath test

Although a driver is legally obligated to comply with a lawful request for a breath sample, some drivers refuse to do so. Refusing a lawful command to take this test results in a one-year suspension of his or her driver’s license. On the other hand, if the driver takes the test and fails, his or her license will be suspended for six months (for a first-time DUI) anyways. The suspension for refusing to take the test increases to 18 months if the driver has refused a breath test on a prior occasion. Further, a second refusal to submit to a breath test is a crime itself. Thus, a driver refusing a breath test—who has previously had their license suspended for refusing such a test—can be charged with a first-degree misdemeanor.

A driver that refuses to take the breath test will typically (but not always) have a stronger defense. Often, the breath test result is the strongest piece of evidence the state has to prove the charges. But, there are other factors that can (and often do) come into play. For example, if a driver looks extremely impaired on the dashcam video, the State Attorney may not even need the breath test result to secure a conviction.

Conscientiousness of Guilt

When a driver refuses to take a breath test, his or her refusal to take such a test, can later be used against the driver at a DUI trial as conscientiousness of guilt. This means, that if the driver proceeds to trial on the charges. the prosecutor can (and will) argue to the jury, that the driver only refused to take the test, because he/or she was impaired. Make sure to contact an aggressive Tampa DUI attorney if you have questions about your rights in this regard.

A driver that refuses to take the breath test will typically (but not always) have a stronger defense. However, keep in mind, the refusal to take such a test, can later be used against the driver at a DUI trial as conscientiousness of guilt.”


Keep in mind, the license suspensions mentioned above only appy to refusal of the breath test, not the field sobriety exercises. Though the refusal of field sobriety exercises can also be used against a driver at trial as conscientiousness of guilt, it will not result in a suspension of their driver’s license. Call a Tampa DUI attorney to discuss this in further detail.

The Law Office of William B. Wynne, P.L.L.C., represents clients in all criminal matters, including D.U.I. cases. Consultations are free of charge, and we offer payment plans to those who qualify. Call today for your free consultation! (813) 532-5057

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William Wynne
Attorney William B. Wynne is a Tampa criminal attorney that aggressively fights criminal charges in the Tampa Bay area and surrounding counties.
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