Challenging DUI Breathalyzer and Field Sobriety Test Results

It’s not uncommon to feel stressed, overwhelmed, and emotional after getting arrested for driving under the influence. Knowing that you have been charged with a serious crime can leave individuals feeling helpless and uncertain about their future.

While every situation is different, in some cases, an experienced attorney can challenge breathalyzer and field sobriety test results. Keep reading to learn more about field sobriety tests, breathalyzers, and how the results might be challenged.

Challenging DUI Breathalyzer and Field Sobriety Test Results

Understanding Breathalyzer & Field Sobriety Tests

Breath alcohol tests measure the amount of alcohol in a person's DNA, also called their blood alcohol content (BAC) level. On the other hand, field sobriety tests measure physical and cognitive impairment. Both tests determine if a person is under the influence of alcohol or drugs and, if so, how intoxicated they are.

How Do Breathalyzer Tests Work?

Breathalyzers use fuel cell technology. When you blow into the device, the alcohol in your breath reacts with special chemicals inside the breathalyzer, creating an electric current. The strength of this current relates to the amount of alcohol in your breath, allowing your blood alcohol content percentage to be determined quickly and without invasive procedures.

In the U.S., a BAC of 0.08% or more is considered over the legal limit for adults 21 or older, while for those under 21, most states have a "zero tolerance" policy, meaning any detectable amount of alcohol in the body can result in a DUI charge. The specific BAC limit varies from state to state but is generally between 0.00% and 0.02%. For example, in Florida, if an underage driver is found to have a BAC of 0.02% or more, they can be charged with a DUI offense.

Typical Sobriety Tests

Field sobriety tests (FSTs) allow law enforcement to determine if a driver's balance, coordination, and cognitive functions are impaired. The most common sobriety tests administered by police officers during a DUI traffic stop are:

  • Horizontal Gaze Nystagmus (HGN) Test: The officer observes the suspect's eyes as they follow a moving object, such as a pen or flashlight, to see if involuntary twitching occurs that may indicate intoxication.
  • Walk-and-Turn Test: The suspect is instructed to take a certain number of steps on the heel to the toes in a straight line, turn around, and then walk back in the same manner. This test assesses balance, coordination, and ability to follow directions.
  • One-Leg Stand Test: The officer asks the suspect to stand on one leg while lifting the other foot about five inches off the ground and counting out loud for a set amount of time. This test assesses balance, coordination, and concentration.

These tests are designed to help officers determine if probable cause exists to charge the driver with a DUI. However, field sobriety tests can be subjective and influenced by external factors.

Can Breathalyzer Test Results Be Influenced?

While breathalyzers can be an effective and accurate means of measuring a person's level of intoxication, several factors can lead to incorrect or misinterpreted results.

Lack Of Calibration Or Maintenance

Breathalyzers are sensitive devices that require regular maintenance and calibration to ensure their accuracy in measuring alcohol content. Calibration involves adjusting the internal settings of the breath alcohol meter to ensure that it provides accurate and reliable BAC readings. This usually involves comparing the device's readings to a known alcohol concentration to ensure the device is measuring correctly.

Maintenance involves checking, cleaning, and repairing the device as needed to keep it in optimal operating condition. This includes replacing worn or damaged parts, checking the device battery, and cleaning the sensor to remove any debris that could affect its performance.

If breathalyzers aren’t properly calibrated or maintained, they can falsely read elevated BAC levels, leading to wrongful convictions of people who aren’t actually over the legal limit.

Use Of Expired Or Faulty Equipment

Older devices may not be properly calibrated, which means they may be unable to provide accurate BAC readings. These older devices may also be incompatible with the latest technologies, guidelines, or updates, further compromising their accuracy.

On the other hand, faulty devices refer to equipment with defects, wear and tear, or malfunctions that may negatively impact their ability to provide accurate BAC measurements. A defective device can produce inaccurate readings that are higher or lower than the actual BAC, resulting in an unfair assessment of a driver's drunken state.

To address these issues, law enforcement agencies must regularly inspect, maintain, and replace their breathalyzer equipment as needed. This ensures that the devices used in DUI cases meet the required standards for accuracy and reliability.

Improper Administration

If the officer administering the test isn’t properly trained or doesn’t use the correct procedure, the results can be skewed. For example, if the officer doesn’t wait for the recommended 20 minutes after a driver's last alcoholic drink before administering a breathalyzer test, it may lead to inaccurate test results.

Law enforcement must ensure that they follow proper training and guidelines when conducting these tests. If not, it could lead to unjustly charging individuals with DUIs and causing potential long-term consequences in their lives.

Can Field Sobriety Test Results Be Inaccurate?

The validity of an on-site field sobriety test is highly dependent on various factors, such as the level of training of the officer administering the test, the physical and health status of the person being tested, and external environmental factors.

Inadequate Training Of The Administering Officer

Officers poorly trained in field sobriety testing may have difficulty giving clear instructions, following proper procedures, or creating appropriate testing conditions. This lack of training can lead to the misinterpretation of a suspect's test performance, resulting in an inaccurate impairment determination.

For example, an officer might mistake a suspect's nervousness, fatigue, or health condition for signs of intoxication.

Additionally, officers without proper training could inadvertently introduce bias or subjectivity into their assessments, skewing test results. This could mean they rely on preconceived notions about the suspect's intoxicated state or misinterpret certain behaviors as signs of impairment.

Inadequately trained officers may also be unfamiliar with other factors affecting a suspect's performance on field sobriety tests, such as medical conditions, disabilities, or environmental conditions. This unfamiliarity can lead to a misdiagnosis of intoxication when other factors are the cause of poor test performance.

Physical Or Medical Conditions Affecting Performance

Even if a person hasn’t consumed alcohol or drugs, certain medical conditions such as inner ear problems, arthritis, and diabetes can affect their motor skills and balance. People with inner ear problems may struggle with balance when asked to stand on one leg. On the other hand, someone with arthritis may have difficulty with coordination when asked to complete a walking test.

A person with diabetes may be disoriented and confused when asked to perform the tests due to low blood sugar levels. Law enforcement needs to be aware of any medical problems a person may have when conducting a field sobriety test and to consider them when evaluating the results.

Environmental Factors

FSTs are used to assess a person's level of intoxication by evaluating their balance, coordination, and cognitive abilities. However, when these tests are administered under adverse conditions, the results may not accurately reflect a person's level of impairment. For example, attempting to walk heel-to-toe on uneven or slippery surfaces may cause even a sober person to lose their footing, causing the officer to question the driver's intoxicated state.

Other non-alcohol-related factors can also contribute to poor performance on field sobriety tests. These include medical conditions, physical injuries, mental stress, and even the type of clothing worn during the test. It's important to question the validity of your test results if you believe any of these factors may have played a role in your performance.

Strategies For Challenging DUI Tests

Given the complexity and potential inaccuracy of alcohol and field sobriety testing, challenging sobriety test results can help build a strong defense in a DUI case. A criminal defense attorney has the skills and expertise to implement strategies to challenge the test results responsible for your case.

Arguing Against Probable Cause For The Traffic Stop

For a police officer to stop you and administer a breathalyzer test, they must have what’s known as "probable cause," which can be based on factors such as erratic driving behavior, traffic violations, or visible signs of intoxication. However, if an officer pulls you over for no apparent reason or based on racial profiling, there may not be sufficient probable cause for the traffic stop.

A lack of probable cause can be used in court as evidence to help challenge the test results. If the judge finds that the prosecution has not met its burden of proof due to insufficient evidence or lack of probable cause, the case may be dismissed even before the defense presents its side.

Presenting Alternative Explanations Or Defense Strategies

An effective defense strategy in a trial is to examine various factors that could have influenced the outcome of your test and present evidence that contradicts the claims made by the officer.

For instance, a defense attorney might argue that certain factors beyond your control, such as medications, medical conditions, or an unusual diet, affected the test results presented by the prosecution. Highlighting these external influences can create reasonable doubt in the jurors' minds, potentially leading to an acquittal or a lesser charge.

Another way to challenge is by presenting evidence that contradicts the officer's observations. This could include video footage from a dashcam or witness statements that provide a different account of events. By showcasing inconsistencies in the officer's testimony, the defense can further cast doubt on the reliability of the prosecution's evidence.

Questioning The Validity Of The Tests And Administration

A DUI attorney can help build a strong defense strategy by questioning the test's validity and the administrator's qualifications. Both breathalyzer and field sobriety tests can have inaccuracies that lead to false positives and wrongful convictions. For example, a breathalyzer may not be properly calibrated or give inaccurate readings after consuming certain products such as mouthwash or cough syrup, or even because of medical conditions such as diabetes.

These tests are also only as reliable as the officer administering them, and if that officer doesn't have the proper training or experience, this may be enough evidence to challenge the case against you. Police officers may not have the necessary training or certification to administer field sobriety tests, such as National Highway Traffic Safety Administration (NHTSA) training. By examining these issues, an experienced DUI defense attorney can effectively challenge the evidence presented against their client and potentially prevent a wrongful conviction.

If you're facing a DUI charge, you need an experienced, dedicated attorney to present your case, especially if you plan to contest a breathalyzer or field sobriety test.

Don't leave your future to chance – contact Weinstein Legal today to speak with an experienced DUI attorney about your case.  Give us a call at (888) 626-1108, or click here to send us an email and schedule a free consultation.

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