Las Vegas DUI cases are rarely cut and dry-even if your breath or blood test came back above the .08 legal limit. As you can see from the discussion below, many things can go wrong. Innocent people can get arrested. Police and prosecutors can make the driver appear much more intoxicated than he or she really is.

Good Las Vegas DUI lawyers put the drunk driving case under a microscope. They expose the flaws in the prosecution’s evidence. They identify the factors pointing to the client’s sobriety.

Below are just a few of the issues that may exist in your Nevada DUI case.

1. The Officer did not Give the Field Sobriety Tests Properly

The National Highway Transportation Safety Administration (NHTSA) has set forth specific procedures for how police are to explain, administer and score certain field sobriety tests. These procedures apply specifically to the horizontal gaze nystagmus test (following a stimulus with your eyes), the one-leg stand test and the walk and turn test.

We find that most police are either not trained in the NHTSA procedures, or fail to execute the procedures properly. A good Las Vegas DUI Attorney can take advantage of these vital police errors, and use them to question the competency of the entire drunk driving investigation. Indeed, NHTSA’s own DUI manual indicates that not following the procedures renders the results invalid.

2. No Probable Cause for the Traffic Stop

Aside from certain checkpoint situations, Nevada police cannot pull you over arbitrarily, merely to see if you have been drinking. To have “probable cause” for the traffic stop, Nevada police must first observe you commit a traffic violation or drive in an incompetent manner. An arbitrary DUI traffic stop (that is, a traffic stop without “probable cause”) violates your rights under the U.S. and Nevada constitutions.

A Las Vegas DUI defense lawyer can challenge the legitimacy of the traffic stop. We do this in court through what is called a “suppression motion.” We cross-examine the police officer and argue to the judge why the DUI traffic stop lacked probable cause. If the judge agrees, he or she will most likely dismiss the case altogether.

3. Mouth Alcohol Contaminates the Intoxilyzer 5000 Breath Machine

Las Vegas police use a DUI breath testing machine called the Intoxilyzer 5000, which is designed to measure alcohol in your deep lung tissue (called the alveoli). The alcohol in this region of the lungs-called alveolar air-is thought to correlate with your true blood alcohol level (and thus to be a roughly accurate measure of your BAC).

However, if the Intoxilyzer 5000 “picks up” alcohol in the mouth or throat, and reads it as alcohol from the lungs, it will give an exaggeratedly high BAC reading. It could read a .15 from a person whose true BAC is a .05.

Among the factors that can cause mouth alcohol to “fool” the breath machine are:

• • Burping, belching or regurgitating near the time of the breath test

• • Dentures, cavities, braces, food impactions, periodontal problems

• • Recent use of cold medicine, mouthwash, cough syrup or breath spray

4. Many of the Field Sobriety Tests are Unreliable

The Federal government has standardized only three of the field sobriety tests (FSTs) in connection with DUI investigations: the horizontal gaze nystagmus, the one-leg stand and the walk and turn. The studies have revealed a slight correlation between (1) performance on these tests, and (2) blood alcohol level.

Yet the Las Vegas police may have asked you to perform various other FSTs during the roadside DUI investigation. Among these may have been (a) estimating 30 seconds with your eyes closed, (b) clapping your hands backward and forwards, and (c) touching the tips of your fingers to your thumb.

Although Las Vegas police routinely give these “other” FSTs, there are no studies or data to validate them as correlating with either BAC or impairment. Moreover, there are no uniform standards as to how to administer or score these tests. Individual officers tend to devise their own arbitrary variations on the FSTs, often asking DUI suspects to perform impossible calisthenics.

5. All of the Field Sobriety Tests Suffer From a High Inaccuracy Rate

Even the three FSTs that have been validated by the federal government suffer from an unacceptably high error rate in measuring DUI impairment. The National Highway Transportation Safety Administration indicates that the one-leg stand suffers from a 35% error rate and the walk and turn from a 32% error rate. The bottom line: 1 in 3 Las Vegas DUI suspects convicted on the basis of these tests would be wrongfully convicted.

6. Non-Alcohol Factors Can Hinder Your Performance on the Field Sobriety Tests

If a drunk driving suspect stumbles or struggles on an FST, Las Vegas police are quick to point to alcohol as the reason. Yet many non-alcohol-related factors can hinder one’s performance on these exercises:

• • Being nervous, anxious or intimidated

• • Improper footwear such as boots, heels or hard-soled shoes

• • Bad weather (especially rain, sweltering Nevada heat or frigid Nevada cold)

• • An uneven or slippery surface

• • Being distracted by onlookers, flashing lights and road traffic

• • Being overweight, elderly, tired, injured or having naturally poor coordination

The point is this: many people who drank ZERO alcohol nevertheless struggle on these exercises. do not despair if you performed less than perfectly. A good Las Vegas DUI attorney can identify the non-alcohol explanations for how you performed, and use them in your defense.

7. We do not Know How You Would Have Done on the Field Sobriety Tests, Even with Nothing to Drink

Any imperfections in your performance on the FSTs, and the Las Vegas police will likely say that you “performed poorly.” The problem, however, is that the police do not know your own baseline when completely sober.

People throughout the population vary greatly in their natural ability to perform these exercises. Some people do great, others have real difficulties. Your performance during the DUI investigation may be roughly the same as how you would perform completely sober.

8. Non-Alcohol Factors Can Explain Driving Defects

Many Las Vegas DUI cases begin with the officer noticing a driving problem, such as weaving, swerving, riding the lane line or driving too slowly for the flow of traffic. Nevada police are quick to attribute such driving defects to alcohol and drunk driving. But here again, many non-alcohol-related factors can explain these driving patterns:

• • Using the cellphone

• • Reading a map

• • Applying makeup

• • Talking to passengers

• • Driving around lost

9. The Officer Lacked Sufficient Evidence to Arrest You for a Nevada DUI

Following the roadside DUI investigation, Las Vegas police cannot arrest you without “probable cause” to believe you were drunk driving. This means that in view of all the evidence, a reasonable officer would believe you were driving under the influence. (Learn about DUI driving patterns and the no-driving defense.)

A Las Vegas DUI Lawyer can challenge the probable cause for the arrest. We can argue that you were alert, coherent and performed reasonably well on the field sobriety tests. If the judge agrees that the arrest was invalid, he or she will most likely exclude from evidence the results of the subsequent blood or breath tests.

10. The Police Never Read Your Miranda Rights

Las Vegas police are only required to read a DUI suspect his or her Miranda Rights (1) after the arrest, (2) if they continue to interrogate the person. Most often, police ask interrogative questions (such as “How much did you drink” and “do you feel the effects of the alcohol”) at the roadside, prior to arrest. In this case, there is no requirement to give Miranda Rights at all.

However, sometimes the police continue to interrogate the drunk driving suspect even after the arrest-and without first offering his or her Miranda Rights. If so, a Las Vegas DUI attorney can probably get any of these post-arrest statements excluded from evidence.

11. Alcohol on the Breath Does NOT Mean You Were Drunk Driving

In their DUI reports, Las Vegas police invariably refer to an “odor of alcohol from the suspect’s breath” as evidence the person was drunk driving. Yet all of the studies indicate that it is impossible to discern whether a person is impaired-and how much alcohol they consumed-from the extent of the odor of alcohol on their breath.

In fact, the chemical that causes intoxication-ethyl alcohol-is really an odorless substance. it is the mixer–such as beer or gin–that produces the scent we associate with alcohol. (If you do not think so, smell the breath of someone drinking O’Doul’s or other non-alcoholic beer).

Some mixers, such as beer, have strong odors. Some, such as vodka, much weaker odors. A person who just finished one beer will likely reek of alcohol much worse than someone who had several dry martinis.

So even if the DUI suspect smelled of alcohol, that does not indicate how much of it he or she consumed. And it certainly does not reveal whether the person was so intoxicated he could not drive safely-which is the standard in a Las Vegas drunk driving case.

12. Acid Reflux or Heartburn Can Contaminate the DUI Breathalyzer

Remember that the DUI breathalyzer here in Las Vegas-the Intoxilyzer 5000-is meant to measure alcohol from the deep lung tissue (as opposed to alcohol in the throat or mouth). that is why police are required to observe the suspect for at least 15 minutes before administering the breath test.

During this observation period, the police must make sure the DUI suspect does not eat or drink anything, and does not burp or regurgitate. it is believed that after 15 minutes, any residual alcohol from the throat or mouth will absorb into the membranes and thus the Intoxilyzer 5000 will only pick up alcohol from deep in the lungs.

But if the DUI suspect suffers from GERD or acid reflux, this can cause semi-digested alcohol to regurgitate into the throat and mouth. The resulting “mouth alcohol” can get blown into the breath machine. When this happens, the breath machine renders an erroneously high BAC. For example, someone with a true BAC of .06 can blow a .16.

If you took a breath test and you suffer from GERD, acid reflux or frequent heartburn, discuss this fact with your Las Vegas DUI lawyer. Your true BAC may be much lower than what the police reports say.

13. The Alleged BAC is Inconsistent with the Other Evidence

If the driver appeared to be relatively sober, yet the BAC comes back surprisingly high, that usually suggests an error in the testing process.

Suppose a person is arrested for a Las Vegas DUI. The breath machine reads .22. Yet the person had driven competently, appeared alert and coherent, and performed reasonably well on the field sobriety tests. The “symptoms of intoxication” simply do not match the BAC reading. When this happens, the reading is usually wrong.

14. The Blood Sample Can Get Contaminated

Contamination may occur throughout the process of collecting, storing and analyzing a blood sample from a Las Vegas DUI suspect. In particular, the vial used for the blood draw must also be pre-loaded with a very specific amount of preservative and anticoagulant. Otherwise, the blood may ferment AFTER it is drawn from the body, creating its own alcohol.

In a drunk driving case involving a blood test, our Las Vegas DUI lawyers can obtain a portion of the client’s original blood sample. We can then have it retested in an independent laboratory.

We want to see (a) whether we get a different result, and (b) whether contamination occurred after the blood was drawn. If so, we may be able to get the BAC results thrown out of court. Or at least, this situation will cast doubt as to the reliability of the alleged BAC reading.

15. Low-Carbohydrate Diets Can Exaggerate Breath Test Readings

Many Las Vegas DUI suspects are on high-protein, low-carbohydrate diets such as the Atkins diet and the Zone diet. These diets cause your body to burn excess fat for energy, a process called ketosis. When this happens, your body releases a substance called “isopropyl, ” which the breath machines mistake for alcohol. Learn more about diabetes as a DUI defense in Nevada.

Indeed, recent studies document how some dieters who drank zero alcohol nevertheless registered a positive BAC on the breath machines. If you are on a low or no carbohydrate diet and your breath reading seems surprisingly high, speak to a Las Vegas DUI attorney about the situation. We may be able to show that biological factors other than alcohol are responsible for the BAC reading.

16. You Were Mentally Sharp

All toxicology experts will tell you that “mental impairment precedes physical impairment.” The first signs of a person’s intoxication are cognitive: slower thought processes, confusion, speaking difficulties.

In a Las Vegas DUI case where the suspect is mentally very quick and coherent-where signs of mental impairment are absent-this is compelling evidence that he or she is NOT under the influence.

17. “Speeding” is NOT Symptomatic of Drunk Driving

Many Las Vegas DUI cases begin with the driver getting pulled over for excessive speed. it is important to note that speeding is NOT a symptom of being drunk.

The National Highway Transportation Safety Administration has compiled a list of types of driving defects that, if observed, suggest the driver is intoxicated. The list includes driving patterns such as “weaving” and “making a turn with too wide a radius.”

Speeding is NOT on the list. There is no substantial correlation between speeding and impairment. In fact, just the opposite is true. The faster the driver is going, the more he must be alert, coordinated and quickly reflexive in order to guide the vehicle correctly. it is very difficult for a truly drunk driver to go 80 or 90 MPH without crashing or nearly crashing.

18. Non-Alcohol Factors Often Explain One’s Appearance of Intoxication

Las Vegas police often point to “objective symptoms of intoxication” as evidence a DUI suspect was drunk. These may include bloodshot eyes, slurred speech, a flushed face and an unsteady walk. While these symptoms could be caused by alcohol, they could just as easily be explained by non-alcohol-related factors.

For example, a person’s eyes may be bloodshot because of eyestrain, allergies or simply being exhausted. Intimidation and nervousness cause mumbling speech and facial flushing. Fear, darkness and adverse surface conditions can cause a person to stumble.

Good Las Vegas DUI lawyers can show the court a myriad of reasons — reasons other than alcohol — for what the police allege to be “symptoms of intoxication.”

19. Range of Error for Both DUI Blood and Breath Test

Even if the breath is working properly and the police administer it properly, there still exists an inherent error rate. Most toxicology experts believe this range of error is +/- .01 to .02 BAC.

This issue is particularly significant in Las Vegas DUI cases where the breath reading is right around the .08 threshold. Someone with a .08 or .09 reading may well have actually been BELOW the legal limit once the error range is factored in.

Note that breath and blood tests typically occur at least an hour after the person was driving. The biological phenomenon of “rising blood alcohol” may cause a BAC test to show a higher level than what the BAC was when the person was actually driving.

20. Sobriety Witnesses May Bolster Your Case

You may have witnesses who can attest to your sobriety. These may be passengers in the car or people you interacted with shortly before the arrest. Though the Las Vegas police will probably say you appeared to be drunk, your witnesses may have a very different opinion as to your condition. They may say that you seemed just fine.

Sobriety witnesses can be a valuable asset to the defendant in a Las Vegas DUI case. If they are willing to testify that you were alert and coherent, that your speech was normal, and that your driving was competent, they can help paint a much different picture of your condition than the police are trying to paint.

In California? Go to our articles on California DUI defenses, the 10 most common California DUI Defenses, and 20 Ways to Beat a California DUI charge, DUI While Driving a Golf Cart.