San Antonio Injury Attorney Blog

In our last blog entry we discussed mistakes breath test operators make during the administration of a DWI breath test . In this blog entry we will discuss other temperature issues involved with the Intoxylizer which a San Antonio DWI lawyer can exploit to create reasonable doubt.

The basic premise of the Intoxylizer is that its results are based on the average temperature of a person - 98.5 degrees Fahrenheit. Yet many people's average temperature vary by a few degrees higher or lower than this number. So theoretically, if the driver's core base temperature is greater than 98.5 degrees Fahrenheit, then the Intoxilyzer will yield a test result that is greater than the true measure of the breath alcohol concentration (BrAC). More often than not, the operators do not take the driver's initial temperature and record it so they can make adjustments off the test results.

In fact, if the case is a Bexar County DWI matter and the breath result was taken in the San Antonio Magistrate's office, there would be a medical professional present at all times who can take the driver's temperature and it would not be difficult.

Another important factor is the tube where the driver blows into the chamber. Many jurors do not know that the tube itself is heated and temperature has to be calibrated. A heated tube can impact the breath sample temperature and consequently the BrAC. The reality is that the technical supervisor for the Intoxilyzer cannot say if the tube temperature was in proper order when the driver blew into the tube. The tube could theoretically be at a higher or lower temperature than recommended.

In addition, there are temperature issues a Comal County DWI defense lawyer can also point out with the chamber. Sometimes, a technical supervisor will argue that the test sample temperature is not significant due to the chamber temperature. This is faulty reasoning because it is a requirement that the test sample temperature be monitored prior to starting the breath test. There would be no requirement to monitor the temperature of the test sample if the heat of the chamber cancelled out the driver's core body temperature.

As noted above, temperature can be a major factor in the ability to challenge the Intoxilyzer results and obtain a favorable DWI defense.

In our last blog entry, we discussed the variance on breath test results for the Intoxilyzer 5000 and how a breath test result of .089 should raise the question of reasonable doubt.

The results on breath alcohol concentration can be affected if there is any alcohol in the mouth. The guidelines require a fifteen (15) minute time period of observation to make sure the mouth is cleared of alcohol. In addition, alcohol in the stomach can get into the mouth if the person belches. That is why if at any time a person belches during the fifteen (15) minute period before giving a breath sample, the person must wait another fifteen minutes before giving a sample.

A strong San Antonio DWI lawyer defense tactic is to query the breath test operator as to whether he keeps a log sheet reflecting the beginning of the observation period and whether that time matches with the time listed on the records. Yet more often than not in Bexar county and surrounding counties, there is no real procedure to reflect when the observation period commences.

Many New Braunfels DWI attorneys will ask the breath test operator if they have video of the breath test and whether they have videotape of the required 15 minute observation period. More often than not, the video is missing. Jurors often question why there is no video of the breath test and the observation period if the prosecutor is relying so heavily on video of the traffic stop . There is a question then as to whether the breath test operator complied with the mandatory 15 minute observation period.

Besides a 15 minute observation period, the breath test operator must verify the temperature of a test sample of fluid. The purpose behind a test of the temperature is to simulate a person's lung. When alcohol evaporates from the blood, it collects in the lungs and leaves the lungs when a person exhales.

The breath test supervisor mixes water and alcohol in a container and pumps evaporated water from the jar into the Intoxilyzer 5000. If the water and alcohol is properly mixed, the test sample will read .08 .The test sample fluid and the evaporated water should be at a certain temperature because a person's temperature can affect breath test results. A temperature higher than 98.5 degrees will create a higher result. The temperature of the test sample must be at 98.5. A technician uses an old-fashioned mercury thermometer to test the temperature of the test sample. In an age of digital thermometers, many jurors will question whether a mercury thermometer is enough of a precise instrument.

More often than not, neither the breath test operator nor the technical supervisor employ a log sheet to record the temperature of the test sample at the time the person is blowing into the Intoxylizer. Again, this omission can be exploited by a skilled Atascosa criminal defense lawyer .

In our last blog entry, we discussed how an Intoxilyzer 5000 has to detect a minute amount of alcohol in a breath sample without error. A Floresville criminal defense attorney must highlight the weaknesses in the machine's accuracy.

Specifically, the test results from the machine are + / - 0.010. A test sample can be off by 0.010 under the Texas Administrative Code . We discussed that the test sample should be 0.080 but in reality, the sample can range between 0.070 and 0.090 and still be considered reliable.

The strongest cases are where the breath sample is between 0.080 and 0.089. If the accuracy rating is + / - 0.10, then the breath sample can be off by 0.010 . Thus, a breath sample was 0.087, then theoretically, the true result could very well be 0.077. Theoretically , the State can argue that the accuracy variation of + / - 0.010 means a breath result of 0.088 could be 0.098. However, that type of variation is further evidence that this machine does not possess the precision it claims.

A jury would be hard pressed to convict beyond a reasonable doubt where the breath sample is below or equal to 0.089.

In addition, the test operator must observe the arrested driver for at least fifteen (15) minutes to make sure the driver does not inadvertently belch causing stomach gas to build in the mouth . Moreover, the test operator has to make sure the temperature is proper on the test sample jar before commencing the test.

You should immediately contact an Austin DWI lawyer especially if your breath test was less than or equal to 0.089.

In our last blog entry, we began our discussion of the scientific formulas behind a DWI breath test on the Intoxilyzer 5000 . The machine's objective is to measure the amount of alcohol in the driver's breath. It is critical for a New Braunfels criminal defense attorney to highlight the weaknesses.

The underlying weakness of the machine is that it supposed to calculate whether there are 0.080 grams of higher of alcohol per 210 liters of breath. Yet the machine does not examine or even hold 210 liters of air. An oil drum containing over 50 gallons holds 210 liters of air. A person's lung holds about 6 liters of air. In reality the Intoxylizer 5000 only holds eighty (80) or so MILLILITERS of air, the equivalent of a soda can.

A gram of alcohol is comparable to an Equal packet. In reality, the Intoxilyzer is attempting to measure eight (8) one-thousandth of that size. If the formula is 0.080g/210L and the Intoxilyzer can only hold eighty (80) milliliters, then that is the equivalent of .00003 grams of alcohol to be proportionate to 210 liters.

What does this mean ultimately ? It means the Intoxilyzer has to detect an incredibly minute amount of alcohol in a breath sample reliably.

To work properly, the driver must exhale 81 milliliter of air into the machine. An infrared light analyzes the molecules in the breath in conjunction with photoelectric cells and a light filter. The photoelectric cell examines the alcohol molecules and measures the amount of alcohol as if the full 210 liters of air were in the chamber. The machine spews out a Test Record.

The printout Test record lists the alcohol concentration with an empty air chamber which should be 0.000 under the heading of Alcohol Concentration. The driver then gives the first of two samples of air by blowing into the Intoxilyzer chamber. After testing the sample, the chamber is flushed with air from the room - there is no filter on the chamber when the air is flushed in. Before the 2nd sample is measured, a test sample is pushed through the chamber for measurement. The test sample is supposed to have 0.080 grams of alcohol in the water. The technical supervisor formulates the test sample. Another sample of air from the room is pushed through the chamber.

The 2nd sample is taken and the chamber is flushed out with room air again. With 2 samples, the jury is instructed to only account for the lower sample. In our next blog entry, we will discuss how a San Marcos DWI attorney can exploit accuracy issues with the Intoxylizer 5000.