All You Need to Know About Breathalyzer’s, BAC’s, DUI’s & DWI’s in The State of Missouri.

One of the most common questions we get from people at Combs Law Group is: “If I get pulled over for drinking and driving should I agree to take the breathalyzer test?”; or for clients who have been arrested for a DWI: “Would it have been better for me to not take the breathalyzer?”. These are the questions you should be asking yourself, and this article will explain in detail, the choice to blow or not blow as well as the consequences of that decision.

For a criminal defense lawyer, the breathalyzer test and the blood alcohol level (or blood alcohol content | BAC) are typically the centerpiece for most DWI cases we fight. Now we don’t condone drinking and driving, and we urge our clients to always drink responsibly. However, we also think that there are many instances where people are wrongly arrested and charged with DWI solely based on a test that can potentially provide bad data on your blood alcohol level.

Therefore, since it’s such a critical factor in the DWI and DUI practice areas, we thought we would provide a thorough overview, from a DWI attorneys point of view, of the breathalyzer testing and some recommendations as to whether to take the test or not.

Unfortunately, it’s not a simple yes or no and is complex, as is the case with most legal questions like this. However, once you’re done reading this article you should have some easy guidelines to remember if you’re ever pulled over by law enforcement and accused of driving under the influence. Or if you’re currently facing a DWI and recently took (or didn’t take) the breathalyzer, you can get a better understanding of your current legal situation. For additional clarity, please call us for a free DWI/DUI consultations at 314-578-1465.

What is a Breathalyzer and how does it work?

First and foremost let’s start with some basic information about the breathalyzer, it’s importance, and how the process works. If you have been drinking alcohol and get pulled over by a police officer for driving while intoxicated (DWI) or driving under the influence (DUI), which are used interchangeably in Missouri, you will probably have your first experience with a breathalyzer test. The breathalyzer test typically involves a device that is used to provide an indication of your blood-alcohol level. The test results are then used by the authorities to issue charges for driving under the influence of an intoxicating substance. If the breathalyzer registers a blood alcohol level of 0.8 or above, you will be arrested and taken to jail in most instances. The breathalyzer is usually a portable device that has been approved by the National Highway Traffic Safety Administration and it detects traces of ethanol in your breath when you blow into it. What the device is measuring is the alcohol concentration in your breath.

When you consume alcohol (Ethanol) it makes its way into your bloodstream after being easily absorbed into the body. It is not a digestible substance. When alcohol arrives at your lungs, through circulation, a part of it can evaporate through the breath when it crosses the lung sacs. The more alcohol you have consumed, the higher the amount of vaporized alcohol passes out of your alveoli. The breathalyzer measures the amount of alcohol in your blood when you breathe out into the device. The stable ratio of the amount of alcohol in your bloodstream, based on the amount of ethanol measured on your breath, is 2,100-breath alcohol to 1 blood alcohol. Which means that when the breathalyzer measures the level of alcohol in your breath, it then converts that measurement to blood by dividing it by 2100. Now that’s quite a bit of scientific jargon, but what’s important here is that the 2100 number is a statistical average, and can vary from person to person. Remember this, because we will come back to this point shortly.

So because of its ability to determine a person’s level of intoxication, the breathalyzer test is an essential device for police officers to instantly determine if a person has been drinking, and potentially under the influence. They do not need to send the suspect off to a lab or to the ER to draw blood, instead, they can get the results immediately by getting the suspect to breathe into the breathalyzer, either on the scene or at the station. A lot of times, law enforcement will conduct a PBT or preliminary breath test, that does not register a BAC, but rather detects if there is any alcohol in your system. Subsequently, they will then perform a blood alcohol level test to determine the specific number.

Most police officers would agree that it can be difficult to know if you are intoxicated or not when they pull you over. They may know that you’ve been drinking, but in many cases, drivers who are over the legal limit can show no signs of intoxication. They can, however, conduct on-site tests to be able to ascertain probable cause (a reading of 0.8 or higher), which means their suspicions, can be confirmed at the scene that a crime has been committed and you will be arrested. This, in essence, makes the breathalyzer the main factor for any DWI case and will be the focal point for any good criminal defense attorney.

Interestingly enough, if you are under the age of 21 in the State of Missouri the Missouri DWI Laws are a little different. Your BAC level has to be 0.2 or less otherwise, you will be arrested for drunk driving. This is due to the zero-tolerance law brought in to try and discourage underage drinking and driving.

Many police officers will tell you that if you REFUSE the breathalyzer, according to the Missouri Implied Consent, you will automatically lose your license for 1 year. If you take anything away from this article, let it be this. THAT IS NOT TRUE. With the help of skilled criminal defense lawyer, there is a way to protect your driving privileges under the right circumstances. Combs Law Group has worked several DWI cases where the client refused the test and was at risk of losing his/her license. Fortunately, with many of those cases, we’ve been able to create a path toward license renewal before the mandatory 12 month period. Contact us today to discuss your options if you refused the breathalyzer test.

The History and Controversy of the Breathalyzer Test

The breathalyzer has been around for a while, so let’s review the history of the test and its infallibility. Research into a breathalyzer device first started in 1874, but it didn’t gain traction until 1902 when vehicles started being manufactured on a large scale. From the outset, there were people who would drive drunk, and the first drunk driving laws came into being in NYC in 1910. Back then the officers would look for signs of intoxication, like alcohol on their breath, bloodshot eyes, inability to walk a straight line or touch their nose. Emil Bogen’s research in 1927 on the comparison of breath alcohol content (BAC) to the subject’s blood alcohol concentration (BAC), led to the development of the drunk-o-meter designed by Indiana University professor, Rolla Harger in 1938. This was the forerunner of the portable breathalyzer device invented by Robert F. Borkenstein in 1954. Over the years the breathalyzer has evolved, where today you even get ignition interlock devices that utilize the latest in fuel cell technology to accurately measure a DWI offenders blood alcohol content. Sadly, all of the innovations haven’t stopped drivers from getting behind the wheel when they are intoxicated.

There has been an ongoing controversy of the validity of breathalyzers as evidence in a court of law. The questions that are frequently asked about the breathalyzer test include:

  • How accurate are the devices?
  • How important are they to a prosecutor in a DWI/DUI case?
  • Can their reliability as accurate predictors of true blood alcohol content be attacked?

If you make the decision to blow and your blood alcohol level registers above a .08 in the State of Missouri, that is just more evidence for the prosecution that you were intoxicated. Unfortunately, often the result is that the defendant will be presumed guilty and will have to attempt to prove their innocence, instead of the other way around. Along with the field sobriety tests, the jurors will have a broader picture of the state of a defendant when they were pulled over by the officer. However, standard field sobriety tests are said to be completely subjective. The true performance might not be reported and the same concerns have been leveled against the breathalyzer for many years.

When a police officer conducts a breathalyzer test, the person agreeing to the test must be continuously observed for 15 minutes before the test is given. If during the 15-minute period the subject smokes, drinks vomits or burps, the observation must be started again to get an accurate reading. If these rules are not observed, a lawyer will be able to challenge the reliability of the breathalyzer test and its admissibility in Court.

Other “Clues” Law Enforcement Officers Use to Determine Intoxication

A DWI enforcement officer in Missouri must have “reasonable suspicion” of wrongdoing before stopping a driver to investigate further. They might notice that a driving violation has occurred or there is unusual driving behavior. These could include things like failing to stop at a stop sign, weaving outside the designated line, failure to use turn signals or wide-radius turns. All of these are “clues” that the driver is not in control of their vehicle and could be driving under the influence of drugs or alcohol. The enforcement officer would need more than “reasonable suspicion” to arrest a person, and will first have to define “probable cause”.

The Missouri State Courts define “probable cause” as: “knowledge of facts and circumstances sufficient for a prudent person to believe a suspect is committing or has committed an offense.” State v. Tokar, 918 S.W.2d 753 (Mo.banc 1996), cert. denied 519 U.S. 933.

In order to make a DWI arrest, there must be legally sufficient probable cause that can be gathered by subtle roadside questioning. If the officer detects the odor of alcohol, with the driver using slurred, incoherent or muttered speech, he would ask the driver to step out of the car to conduct DWI standard field sobriety tests (SFST). The fact is that the bar is very low when it comes to probable cause for a DWI. An officer can merely smell alcohol coming from inside the vehicle and have probable cause for conducting a field sobriety test.

The Standardized Field Sobriety Test (SFST)

Police officers who are trying to determine the level of inebriation of a driver usually conduct The Standardized Field Sobriety Test (SFST), promulgated by the NHTSA in 1981, comprises 3 different tests to gauge if a driver is impaired. These three tests, developed in the 1970’s, are the horizontal gaze nystagmus (HGN), one-leg stand and the walk-and-turn tests. The findings of these tests are admissible as evidence in a court as they have been scientifically validated and are adopted by most states in the U.S.

The HGN test involves an officer observing the eyes of a drunk driving suspect as they horizontally follow a slow-moving object like a small flashlight or pen. Horizontal gaze nystagmus refers to the involuntary jerking of the eyeball as it gazes to the side. In a normal person, nystagmus will only happen when the eyes are rotated at high peripheral angles. There are three indicators of impairment due to intoxication: if the eye is unable to track or follow the moving pen or finger smoothly, if the eyeball jerking is distinct and sustained nystagmus when the eye reaches maximum deviation, or if the angle is 45 degrees of center prior to the onset of jerking. Therefore, it is very difficult to “cheat” your way past this test, since it measures your involuntary eye movements. However, this test is often challenged in Court by diligent criminal defense attorneys.

The walk-and-turn test involves getting the subject to take 9 steps along a straight line, touching heel-to-toe and then turning on one foot to return in the opposite direction again walking heel-to-toe. There are 8 possible indicators of impairment:

  • If the balance cannot be maintained while listening to the police officer’s instructions
  • If the subject starts walking before the instructions have been completed
  • If they have to stop midway to regain their balance
  • Is unable to touch heel-to-toe
  • Needs to use arms to balance
  • Steps off the line
  • Takes the wrong number of steps
  • Makes an improper turn

A validation study of this test conducted in 1998 found that 79% of subjects who exhibit two or more of the above indicators will have a blood alcohol level of 0.08 or higher on the breathalyzer test.  However, that leaves 21% of those who failed the test were sober. Therefore, failing these tests does not mean that a good DWI lawyer cannot challenge the validity of the tests or if they were performed properly.  The one-leg stand test involves the subject standing with one foot approximately six inches off the ground. At the same time, they have to count aloud beginning with one thousand until they are instructed to put their foot down by the officer. This test is usually conducted for 30 seconds as the officer looks for 4 indicators of impairment:

  • Swaying while attempting to balance
  • Using arms to balance
  • Hoping to attempt to maintain balance
  • Putting the foot on the ground

83% of individuals who exhibited two or more of these indicators in the performance will have a blood alcohol level of 0.10 or greater (1998 validation study). Again, that leaves a 17% chance that the test is wrong.

The officer is expected to ask a DUI suspect is there is any reason why they can’t perform these three tests. The subject’s answer must be recorded in the report. For example, they might be suffering from an eye condition that would give a negative result on the HGN test or perhaps the person is struggling with an injury/disease, which would not allow them to execute the one-leg test effectively. This test is to be performed on a flat service, in a safe area. There are many issues that a criminal defense attorney can use to challenge these tests, from the conditions in which you take it to the shoes you are wearing when the test is performed.

You’ve probably heard people often joking “I couldn’t do that if I was sober.” when talking about field sobriety tests. It’s true, as we’ve just uncovered a certain percentage of the population are unable to perform the specific tasks in the test while sober. Which opens up some serious questions about the validity of the testing itself. Unfortunately, police officers don’t typically take these factors into consideration and will likely charge someone with the DWI or DUI even if they are legal under the limit and refuse the breathalyzer.

Another critical part of this post and something you should always remember is that the police are there to investigate a crime. Their investigation is in turn sent to the prosecutor who evaluates the evidence and then actually issues the charges depending on the evidence. Therefore, the police do not have discretion when it comes to charging a crime, which is solely in the hands of the prosecuting attorney’s office of that jurisdiction. They are trying to do everything in their power to gather as much evidence as possible. So the more you say and the more you cooperate, the more likely it is that the charges will be filed. Most criminal defense lawyers will tell you it’s best to keep quiet and do the bare minimum for the police officer.

The Problem with Breathalyzers…

Another big factor is that breathalyzers have been known to produce false, invalid and inaccurate results. This can be due to improper calibration required for changes in ambient temperature. A subject’s pattern of breathing can seriously affect tests validity. If you hold your breath for 30 seconds, you could see a BAC levels rise from .07% to .081%. Also, hyperventilation can lower the blood alcohol level, thereby giving a false reading. It has been discovered that breath test results (BrAC) are 15% higher than blood test results. The machine could also be faulty from lack of proper maintenance.

Another factor is that diabetics (and undiagnosed diabetics) have acetone (which tests as ethanol) levels that can be hundreds or even thousands of times higher than a normal person giving higher BAC readings. Therefore, it’s important to note that 3 out of 10 people are undiagnosed diabetics. Furthermore, high acetone levels can also be found with people on specific diets like the “Watkins diet”. In sum, a qualified and experienced DWI lawyer or DUI lawyer has many ways to challenge a breathalyzer.

If a person works with substances like paint, cleaning solvents, ethers, lacquers or other alcohols as part of their jobs, they could show a false positive result. The aforementioned ratio of 2100:1 is not a true number for all people as an individual’s partition ration can vary from 1300:1 to 3000:1.  If a person has just consumed an alcoholic beverage, the alcohol in the bloodstream is still in the absorptive phase and will register a very high BAC where the actual level is much lower in the bloodstream.

A disease like periodontitis and acid reflux can also result in “alcohol” being present in the mouth, which results in an invalid test. People who have been smokers for many years also test with higher BAC levels because of the presence of acetaldehyde in their systems. Even Radio Frequency Interference (RFI) can affect the validity of a breathalyzer test.

The elements impacting the test all relate back to the time of the test, the results of the test, the time of the driving, the time of the last drink consumed and the last known food eaten. The computation of all of these factors used in a DUI/DWI case is commonly known as retrograde extrapolation. But the bottom line is that the breathalyzer test is not exactly a foolproof test. It can throw false positives under a variety of circumstances, which makes it a dangerous component to any DWI case.

If you haven’t been drinking very much and you’re asked to take the test, you might be better off asking for a blood test. It will take time to get to a hospital, get your blood drawn and tested, all things that can put more time between your last drink and when your BAC is tested.

The Process from Arrest to Agreeing to A Breathalyzer Test

As stated previously there must be probable cause for a traffic stop and a subsequent DUI or DWI arrest. If the officer concludes that the subject has alcohol or drugs in their system, they do not necessarily have to perform a breathalyzer test at the scene. They can take the person to the police station or hospital for an evidential specimen (breath, blood or urine) especially if a breathalyzer device is not available. If a driver refuses to take the breathalyzer or SFST tests without a “reasonable excuse” they can be arrested under the “implied consent” law. If they do agree to the breathalyzer and they are not over the legal limit this does NOT automatically mean that you are off the hook.

As mentioned above, the police officers investigation in a DUI or DWI arrest is very much subjective, and you can be found under the influence with a blood alcohol level under .08. While this is rare, we have seen it. If you fail the test, you will be taken to the police station where two more breathalyzer tests will be conducted. The specimen that yields the lowest reading will be the one submitted to the prosecution as evidence. If at any point you refuse the tests or evidential specimen, you will be informed that they will be rendered liable for prosecution –it is a criminal offense after all and requires the help of the very best criminal defense lawyer available to you.

In Missouri, under Missouri Implied consent it will automatically result in a one-year suspension of your driver’s license. However, as mentioned above, this is often used as a scare tactic by law enforcement to elicit a BAC, as this bolsters their claim that you are driving under the influence. It is not an automatic one-year suspension. If you do indeed refuse ALL tests and you have never had a DUI or DWI before there are legal remedies to challenge the validity of the refusal (which is an issue in many cases), and you can never lose your license. Furthermore, there are filings that a criminal defense lawyer can make to challenge whether or not you were intoxicated, this is called a Petition for Review (PFR).

In some cases, a police officer can request a judge to issue a warrant for your blood if you refuse the breathalyzer. If that occurs, you’ve likely been involved in a DWI accident. Blood samples must be taken by a doctor or registered health care professional and split into two vials. One vial goes to the police forensic laboratory for analysis and the second vial is given to the person in order that they can independently test the specimen. Urine samples do not need to be taken by a doctor and two samples must be provided within one hour of arriving at the station/hospital.

Missouri Law on Submitting to Blood Alcohol Tests

So, you might be thinking at this point it’s best to just refuse all the tests since they’re all designed to give the police more evidence. Unfortunately, it’s not that simple. Missouri’s “Implied Consent Law (RSMo § 577.041) states that every driver is deemed to have given their consent to a blood-alcohol test after being arrested upon the reasonable belief that they were driving while intoxicated. There are administrative sanctions given out by the Missouri Department of Revenue Driver License Bureau. You can ask to speak to your lawyer and the officer must give you twenty minutes to call them and have a conversation. The arresting officer will take possession of the valid Missouri driver license and issue a 15-day permit. You essentially only have 15 days to get a Petition for Review of Revocation or Stay Order, to overturn the revocation of the driver’s license. Time is of the essence at this point and you need to get an attorney to assist you with filing this petition on your behalf.

How You Can Challenge the Test Results in Court

With a skilled criminal defense lawyer by your side, you can put up a challenge to your test results in court. The ways and means are determined on a case by case basis, however, here are some examples of legal justifications for the courts to throw out the test results or the entire case:

  • You can contest the legality of the initial traffic stop. A law enforcement officer in Missouri is not allowed to stop a motor vehicle without probable cause or reasonable suspicion. So, an officer can’t pull someone over just because they have witnessed him or her exiting a bar.
  • There has to be a traffic violation or evidence of some criminal behavior before they can pull a car over. If the stop is deemed illegal all evidence obtained as a result of that specific stop may be suppressed.
  • You can challenge the police officer’s observations. Perhaps your bloodshot eyes are a result of allergies, not alcohol, for example.
  • You can challenge the findings of the SFST. These tests are subjective and rely on the police officer’s interpretation.
  • You can request the records of the maintenance check of the breathalyzer device used. They have to be checked every 35 days.
  • If the breathalyzer test was improperly administered by failing to follow the proper procedure you can challenge the findings. A Missouri court will also require proof that the test was properly executed using state-approved techniques by a person holding a valid permit using approved equipment.
  • You can challenge the breathalyzer results. If a test is only administered hours after the stop, they could have a higher BAC level than when they were initially pulled over as it takes a time for the body to absorb the alcohol.
  • If mouth alcohol gives a false positive of a high BAC level. (e.g. mouthwash or spray or cold medication)
  • If the police officer failed to conduct a 15-minute observation period.
  • If the blood test was not conducted by medical professionals or specific procedures were not followed to the letter.
  • If the law enforcement officer failed to give the driver all of the required warnings, notices or did not read the individual his or her Miranda rights.

Conclusion: To Take the Test or not to Take the Test?

It is not ideal to have to refuse a breath, blood or urine test if you are arrested for a DWI or DUI. However, you cannot be forced to give a sample. Ultimately, you have to gauge your level of intoxication and make a decision at the time you’re pulled over. Meaning, if you think you have a chance of blowing under .08, it is almost always worth a roll of the dice. However, in most circumstances, it usually better to refuse ALL tests, otherwise, you’re just providing more evidence of your intoxication. A Missouri DWI arrest could be the start of a long journey as it could take months before charges are filed.

The DWI statute of limitation for the filing of a charge is one year according to Missouri law, specifically section 556.036 with felony crimes having a three-year deadline. You should therefore immediately start building your defense with the help of an attorney well versed in the Missouri DWI laws. If this is your first DWI in Missouri, you will be able to avoid jail time, but if this is a second offense or more you can end up looking at jail time if you do not hire a qualified and experienced DUI/DWI defense lawyer. A second offense could also come with an ignition interlock device (IID) installed in your car along with the one-year license revocation. However, you can still be found guilty even if they do not have proof that your BAC level was above .08%.
Give us a call at 314-578-1465, or fill out the contact form, so we can talk you through the process ahead and assist you with your DWI legal defense regardless of whether you provided a blood or breath sample. We’re here and we’re listening and want to help you fight the hard fight.


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About Chris Combs

A St. Louis native and graduate of Saint Louis University Law School, Chris Combs has been recognized as one of St. Louis' top criminal defense and personal injury attorneys. He is passionate about getting positive results for all his clients and values personal communication above all.

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