As a motorist in Texas, the legal blood alcohol concentration (BAC) limit is 0.08%. If a DWI blood or breath test reveals that you were driving with a BAC higher than the Texas breathalyzer limitations, you could face additional DWI charges. In this blog, we take a look at the various elements of the Texas DWI testing process.
Breath Testing and DWI
If a law enforcement officer pulls you over and reasonably suspects you were intoxicated and driving, the officer would likely have you administer field sobriety tests. Officers are trained to take action based on the results of these tests, so if you fail, you'll likely be arrested.
Even sober individuals often fail field sobriety tests. The police officer will then request you to blow into a device called an Intoxilyzer, generally known as a breathalyzer, to determine your alcohol level after they have placed you under arrest. If your breath alcohol concentration level is 0.08 or more, you are considered legally intoxicated as per Texas Law.
However, the prosecution has the burden of proving that you had been driving while intoxicated by alcohol or drugs. The breath test often takes about 45 minutes or more from when you were driving.
The following are the legal blood alcohol concentration and breath alcohol concentration limits in Texas:
- 08% for individuals aged 21 and above
- 04% for motorists holding a commercial driver's license
- Any detectable amount for individuals aged 20 and below
Most people arrested for driving while intoxicated believe their guilt is determined solely by their BAC level. Even though the latter could be accurate (i.e., there is an assumption that you're guilty), this does not make you legally guilty. Hiring an attorney who is well-versed in both criminal DWI defense and breathalyzers could decide whether the charges are dropped or the defendant is found not guilty.
The Texas Breath Testing System
The state of Texas has recently mandated the use of the Intoxilyzer 9000 as the exclusive breathalyzer equipment. Texas has only recently started using the equipment, whereas other states like New York, Colorado, and Georgia have had it for years.
The Intoxilyzer 9000, like other traditional breathalyzers, operates on the principle of infrared spectrometry (IR). This theory involves the absorption of infrared light. The Intoxilyzer 9000 analyzes breath samples for traces of alcohol and determines the alcohol content. Since ethyl alcohol has a distinctive infrared absorption spectrum, this technique utilizes infrared light to detect and measure the presence of ethyl alcohol.
Breath alcohol concentration is determined by measuring both the rate of absorption and the concentration of alcohol in the breath sample. The Intoxilyzer 9000 measures alcohol in grams per 210 liters of breath, as mandated by Texas PC 49.01(1a.)
Techniques for Conducting Breath Tests
All breath alcohol testing instruments intended for use in Texas courts must comply with standards outlined in the state's Breath Alcohol Testing Regulations. These are some of the necessary conditions:
- Expired breath samples should be examined
- The result from the equipment should be within 0.01 g/210 L of the actual value or limitations established by the Scientific Director, and the equipment itself should include a reference system
- Breath specimen tests to determine alcohol content for law enforcement require adequate and acceptable procedure details
- Any additional tests the Scientific Director deems appropriate for a thorough and accurate analysis of routine breath alcohol testing
Additionally, the Texas Breath Alcohol Testing Program mandates that an inspection be conducted whenever equipment is taken into or restored to service. Before putting an Intoxilyzer 9000 into operation, an ABA test should be performed, during which a radio frequency signal will be transmitted to guarantee radio frequency detection. Every active testing site needs to be inspected at least once every calendar month.
According to the Texas Breath Alcohol Testing Regulations, the operator administering a breathalyzer should observe the individual for 15 minutes before the test to ensure that no foreign objects are placed in the mouth. The mandatory waiting period can only be administered by trained professionals using breathalyzers.
Most Texas law enforcement officers use the Intoxilyzer 9000. The breath testing device requires the individual to blow into it with enough force to sound the tone for a predetermined amount of time. This aims to satisfy the slope detector, which measures the rate of change in the breath sample's alcohol concentration. The Intoxilyzer 9000 will automatically stop the test after 3 minutes if the individual has not provided a sufficient breath sample.
The following elements should be included in every test to ensure that it is administered correctly:
- Air blanks should all be 0.000
- There should be no more than the allowed limit between the individual's two outcomes
- Both sets of findings from the calibration verifications and the temperatures of the reference sample solutions should be within the allowable range
- Test completion should be entered in the Sequence of Analysis section
- The operator's signature is required
Records on simulator and instrument repairs and maintenance should be recorded in the Maintenance File. This should include a copy of information captured during the inspection of every certified piece of equipment. All repair and maintenance notes for each piece of equipment included in the Maintenance File must include the equipment or simulator's name, the serial number, and other identifying information, the date of the service, the name of the person who conducted the servicing, and a description of the service that was done.
Machine Errors and Unreliability in Breathalyzer Results
There are a lot of issues with breath testing that need to be addressed. To begin, a breathalyzer cannot determine how much alcohol is present in the body or the blood. Breathalyzers detect alcohol after it has evaporated from the bloodstream and entered the individual's airway. However, the equipment (and the law enforcement officers) believe that a high breath alcohol level is equivalent to a high blood alcohol level. This is a false assumption. Although there is a connection, it shifts and changes depending on several factors.
Factors That Affect the Connection Between Blood Alcohol and Breath Alcohol
Three key factors can change the correlation between blood alcohol content and breathalyzer results:
- Breathing technique
- Breath/blood partition ratio
The breath sample's temperature can make a huge difference. The warmer the body temperature, the faster alcohol absorbs into the lungs from the blood. Generally, a higher BAC reading corresponds to a higher core body temperature. This is worsened by the fact that the body temperature varies by degree. The breathalyzer believes the body temperature is 34 degrees Celsius. A single degree above 34 degrees Celsius increases an individual's blood alcohol concentration by 7 percent.
- Breathing Technique
In addition to body temperature, how you breathe can affect your blood alcohol concentration reading. The BAC findings can be as much as 20% higher than the actual BAC level if you have a shallow breathing pattern. The breathalyzer has no way of knowing how deeply or quickly you breathed before blowing into it, nor can it tell how you inhaled at the precise instant you blew into it.
- Breath/Blood Partition Ratio
Breathalyzers rely on the partition ratio, which is one of its underlying principles. Breathalyzers in Texas, as everywhere in the United States, use a 2100:1 ratio between blood and breath.
So, if there's one part alcohol on the breath, there are two thousand and one hundred times as many in the blood. The concept is easily explained by considering the following ratio: the amount of alcohol in one milliliter of blood is equivalent to the amount of air in two and a half hundred cubic centimeters of lung air.
However, research shows the exact opposite. Several studies have shown that this ratio is deceptive and that a range, rather than a single value, provides a more accurate picture. The volume of air in a person's lungs to the volume of blood in a milliliter can vary anywhere from 990 to 3005 cubic centimeters.
You might be wrongfully arrested if your ratio is below 2100, which is a realistic possibility. The ratio of your blood to breath is not the same as your brother's, mother's, friend's, or even your own, and it can vary over time.
The phases of absorption add to the complexity of this breath-to-blood ratio. Everybody's rate of alcohol absorption varies. If you take alcohol after having a meal, it could take up to five hours for it to absorb completely, whereas having nothing in your stomach could take anywhere from one to two hours.
However, breathalyzers presume that you have already entered the postabsorptive state. It's extremely difficult to tell if a given blood alcohol concentration (BAC) level is reflective of a person's actual state without knowledge of their absorption phase.
In this instance, the issue is less with the breathalyzer's functionality but with the results not being in line with or accurately recognizing the purpose of use. Officers utilize the equipment as though the results are unquestionably accurate when in fact they are simply intended to produce an approximation.
Breathalyzers are calibrated for the typical male rather than the ordinary female. Average scores for females are greater than those for males, and this is in part because of the latter. The machine makes the presumption that everyone who blows into it is the same gender and weight, which could lead to inconsistent results and, in certain cases, errors that are legally, emotionally, or monetarily detrimental.
Your present health may also affect the breathalyzer test results. especially if you have certain medical conditions, such as diabetes, gum disease, heartburn, liver disease, fever, or heart disease, or are taking certain medications. Some diets, especially the keto diet, which could affect one's body, can potentially affect the test.
Rising Blood/Alcohol Levels
Even if you weren't driving while inebriated, there are times when a test will show a blood alcohol percentage over 0.08 percent. A rising blood alcohol case is one in which the driver's BAC increases between the time of driving and the time of testing.
After consuming alcohol, it could take about three hours for it to enter the system. Even if you weren't intoxicated while operating the vehicle, you were once the breath test was conducted.
Since the point of the testing is to see if you were impaired while driving, an inaccurately high BAC test result could be misleading.
The breathalyzer test administered for DWI may not always be an accurate indicator. It does not directly measure blood alcohol concentration but rather calculates it from the level of alcohol detected on your breath.
Radio Frequency Interference
Radio frequency interferences could cause problems for the Intoxilyzer 9000. If the radio signal from a nearby mobile phone or police car is particularly powerful or close, the device could malfunction. Even though the Intoxilyzer 9000 is equipped with an automatic detecting mechanism, its accuracy is not completely guaranteed. The results might be tampered with, and interference could affect the BAC test.
In Texas, lawmakers and police officers are aware of these problems, but they do not do anything about it because they're more focused on making arrests. The Intoxilyzer 9000 permits a difference of 0.20 between 2 breaths. In this way, you can be subjected to two tests by law enforcement, with the possibility that the outcomes will have a difference of 0.02. This presents a challenge.
If you were found to have a blood alcohol concentration (BAC) of.08 on the first test and 0.06 or 0.10 on the second, you'd be found to be under the legal threshold on the first test and significantly over the legal limit on the second.
It complies with both Texas customs and state law. In reality, it would be "scientifically consistent," thus charges and subsequent convictions can occur if you do not consult an attorney who can identify these problems and effectively address them.
Poorly Maintained Breathalyzer Devices
Poor calibration or maintenance of the breathalyzer could result in erroneous results, even when everything is working as it should. Breathalyzers should be serviced often; else, they develop flaws.
Some instructions dictate how breathalyzers should be maintained, including how regular maintenance should be performed. Due to the high volume of daily operations, routine maintenance of testing devices at police stations can often be skipped. This leads to inaccurate results.
Breathalyzers need a lot of care to function effectively over time. Its ability to perform accurately is compromised if maintenance is neglected.
You should consult an experienced attorney who can recognize a poorly maintained device. Of course, every case is unique with its own set of facts, and your attorney should be well-versed on the flaws and shortcomings of breathalyzers, and carefully expose them in the course of your case.
Poorly Administered Breathalyzer Tests
Texas has only recently adopted the Intoxilyzer 9000, therefore all police must get training on how to use it. Breath test failures are always the result of incorrect Intoxilyzer use. The following considerations should be made if you are asked to undergo a breathalyzer test:
- Has the officer waited the required fifteen minutes before conducting the test? The Texas Breath Alcohol Program Operator Manual states that the fifteen-minute waiting time is necessary to verify there's no residual alcohol remaining
- Has the mouthpiece been used or not? Always use a fresh, unused mouthpiece
- Was the police officer trained to use the Intoxilyzer? Otherwise, they were not allowed to perform the test
- Were the results of the external tests within a reasonable range? If the value did not fall within the expected range of 0.075 to 0.085, the data should be suppressed
It's also worth noting that the Intoxilyzer 9000 has several other features that could come in handy. For example, it can generate histograms.
Legal Defenses Against Breathalyzer Tests
As said, the Intoxilyzer 9000 and other breath-testing devices require routine maintenance. All tests completed using the instrument could be excluded from admission into evidence if the essential tests are not performed.
An incorrect breath test result could be the result of poor maintenance. Other times, tests could be thrown out because they were conducted by someone without the right qualifications. False positive results in blood tests can be caused by several factors, including improper sample processing or testing. Again, only certified people should conduct tests.
It would be in your best advantage to act swiftly to acquire legal representation if you have been detained for DWI in Texas after either consenting to or refusing to undergo a breathalyzer or blood test.
Find a Fort Worth DWI Defense Attorney Near Me
Your professional and personal life could both suffer after a DWI conviction. If you have been arrested for DWI, you might believe that there is little you could do to defend yourself, but that's not always the matter. You may never know everything there is to know about the case unless you consult with an attorney first.
If you need legal representation for a DWI in Fort Worth, Texas, contact the Fort Worth DWI Defense Lawyer today to find out more about our services. We are committed to doing all in our power to ensure that you get a favorable outcome for your case. Call us at 817-470-2128.