San Antonio Injury Attorney Blog

In our recent blog entries, we discussed DWI defense techniques against Field Sobriety tests . Today, we will focus our discussion of Jourdanton DWI criminal defense by examining the Intoxylizer 5000 and a defense against a breath test over the legal limit.

A San Antonio DWI lawyer will have the TX Breath Alcohol Testing Program Operator Manual at his disposal as he prepares to defend against a breath test result from the Intoxilyzer 5000. Many ever-changing factors influence the machine (and the results it spews out), and these conditions will lay the foundation for challenging the accuracy of the breath test.

The Intoxilyzer 5000 simply has too many flaws to be used to prove results beyond a reasonable doubt. Much like a computer or vehicle, the machine is prone to malfunctions and inaccurate, unreliable results due to maintenance, operator error, lack of proper calibration, and simple glitches. Jurors can very well sympathize with the reliability issues associated with the machine especially if they have encountered problems with a computer or car.

The Intoxilyzer is based on a formula of 0.080g/210L. Essentially, eight (8) one hundredths of a gram has to be detected in two hundred ten (210) liters of air. TX Penal Code Section 49.01 outlines the same blood alcohol content of .08 - a blood alcohol content (BAC) over .08 means the person is intoxicated at the time of testing.

In order to convert the blood alcohol content (BAC) to an equivalent breath alcohol content (BrAC), the TX Legislature determined that 210 liters of air converted into 100 milliliters of blood. So , here are the equivalent formulas:

BAC - 0.080g/100ml of blood
BrAC - 0.080g/210L of air

When trying to prove the BAC through the equivalent breath sample, the prosecution calls upon the breath test operator and the technical supervisor. The breath test operator will discuss proper administration of the test to the driver and the Test Record, which is a piece of paper reflecting the quantities of alcohol per 210L of air. The supervisor will discuss the reliability of the Intoxilyzer 5000.

In our next section, we will discuss in further detail how a San Marcos DWI lawyer can attack the reliability of the breath test.

In our last blog entry, we discussed weaknesses a San Antonio DWI lawyer could utilize when defending against the Walk and Turn . Today, we will discuss the final Field Sobriety test - the one-leg stand (OLS).

During this test, the driver stands with his feet together and arms at his sides. The police officer relays the instructions which involve lifting one leg six (6) inches off the ground while counting out loud. Under NHTSA regulations , the officer must time the event for thirty (30) seconds, but the officer does not tell the driver the length of the test. The driver is intoxicated if he cannot perform the test for the thirty (30) seconds.

Interim signs of impairment during the test include swaying, using the arms to balance, hopping, and putting the foot down. A New Braunfels TX DWI lawyer can argue against a video that shows the client hopping or putting his foot on the ground. Perhaps the ground was uneven and a client who catches himself rather than falls is not really impaired. Wind is also a factor that can cause a person to lose balance and the video will often reflect the weather conditions.

A San Marcos DWI lawyer may also obtain medical records reflecting the driver suffered from back or knee problems or a neurological deficit - medical issues play an important role in performance on field sobriety tests. Many times, a criminal defense attorney may ask the officer to perform the field sobriety test, but this technique can backfire if the arresting officer performs the tests correctly. In cases where the officer performed the test correctly, a strong argument is that the officer may have performed the tests numerous times before, and the driver had to perform these tests for the first time.

In our last blog entry, we began our discussion on effective San Antonio and greater Bexar County DWI defense strategy of the Walk and Turn (WAT).

Normally, even the most sober of drivers will utilize their arms to maintain a semblance of balance when standing with one foot in front of the other , heel to toe, while turning to listen to an officer? It is not a normal starting position, and most officers will reply it is unusual and that some use of the arms is usually necessary to maintain balance.

On the video, based on NHTSA guidelines, an officer will only do 3-4 steps and they usually reply that they are only trained to show three to four steps. Immediately, you can perk up the jury's attention by pointing out that the officer did not perform the entire test as he had demanded of the driver on the date of arrest.

According to the NHSTA manual, there are a total of eight (8) clues as to proper performance on the WAT. In reality, however, the WAT in essence consists of eighteen (18) steps - 9 one way, the turn around, and 9 steps back. That is well over 25 tasks the driver must perform correctly to pass - it not simply 8 clues. If a driver performs a mistake in stepping only 2x, he has still performed over 90% of the tasks correctly, which is excellent on a test people normally do for the first time in their life when they are asked to perform them on a Jourdanton DWI stop.

The NHSTA Manual makes the bold prediction that failures on field sobriety tests equate to a Blood Alcohol Level of greater than .10. There is absolutely no scientific foundation for such a claim. Many prosecutors will try to sneak it in by asking the officer to comment based on his experience what the Blood Alcohol Level of a person failing the tests would approximate. Regardless of experience, an officer is simply not qualified to comment, and the lack of scientific basis underscores that inability to estimate.

Never submit to a Field Sobriety Test. If you have been charged with a Texas DWI, contact a San Marcos TX DWI attorney immediately to learn the best defense.

In our last blog entry , we completed analysis of the criminal defense of the Horizontal Gaze Nystagmus (HGN) test.

The next major test a New Braunfels DWI lawyer must overcome is the Walk and Turn (WAT), where the driver is instructed to walk heel-to-toe while counting in a loud voice with each step. In this test, the driver will walk nine (9) steps , turn around, and walk back nine (9) steps. All steps are heel-to-toe. In this test, the arresting officer wants to highlight the inability of the driver to maintain his balance and / or a failure to properly follow instructions.

According to the National Highway Traffic Safety Administration (NHTSA) Manual, there are eight (8) potential clues. If the driver fails on at least 2 of the clues, then the theory goes that the Blood Alcohol Level (BAC) is over the legal limit of .10. During the test, the driver may make mistakes such as stepping off the line. The Manual states the person has failed the test if he steps off the line more than 3x. Any evidence that the driver is about to fall and injure himself is also enough to demonstrate a failure on the WAT.

According to the NHTSA, the accuracy of the Walk and Turn approaches 70%, which is not exactly a strong indicator of reliability. The theory goes that a failure of all three tests (HGN, WAT, and One-Leg Stand) demonstrates enough reliability to show intoxication over the legal limit.

A San Antonio DWI attorney must carefully review the videotape of the Walk and Turn to aggressively defend against this test. The first point of attack is the starting position. In the WAT, the driver is supposed to place his right foot forward, placing the heel of his right foot against the toe of the other foot. He may not use his arms to balance and the arms must be at his sides. Simultaneously, the arresting officer will position himself to the side of the driver and begin instructing him on conducting the WAT. The driver will inevitably turn his head or body to listen to the officer while he stands in this position. Sober drivers would have a hard time maintaining this position without using their arms to keep from stumbling. Thus, from the outset, the WAT is designed to make a person look foolish.

During trial, the prosecution may ask the officer to come down from the stand to demonstrate a field sobriety test. Rarely does an officer assume the starting position demanded during the WAT. A strong DWI defense tactic is to question the officer on a normal standing position - feet shoulder width apart and arms dangling. More often than not, that is exactly how the officer will initially stand when he explains the tests.

In our next blog entry, we will focus on additional ways a Comal County DWI lawyer can attack the Walk and Turn Field Sobriety Test.

In our last blog entry, we discussed some ways to attack the validity of the Horizontal Gaze Nystagmus (HGN) test.

During a jury trial, the jury will review the video, but it is highly unlikely that they can pick up the subtle bounce or nystagmus of the eye from the video. They are essentially relying on the officer's testimony that he witnessed clues of intoxication related to nystagmus. A jury will be extremely doubtful of the officer's observations, if a Bexar County DWI attorney can demonstrate that the officer has written reports with mistakes, that his testimony differs from the video, and that he did not perform the HGN test according to NHSTA specifications.

An especially strong tactic is when the officer claims that the driver was swaying and unable to stand steadily. Well, the inevitable question when an officer testifies like this, is how on earth he could possibly estimate a 45 degree angle for onset of nystagmus if the driver is swaying? The officer will either claim he could detect the nystagmus before a 45 degree angle was reached on a person moving back and forth or that somehow the driver was able to stand still throughout the HGN field sobriety test. The officer will inevitably contradict himself and the jury will cast doubt on his credibility. Any swaying during the HGN will ultimately render the HGN test invalid. If the officer contends the driver was swaying but then remained still during the HGN test, the jury will question whether in fact the driver was intoxicated if he was able to stay still during the entire administration of the HGN test.

Another key weakness of the HGN test brought out by the DWI video is that very rarely does the driver give his permission for the officer to do the test. Nor does the officer ever ask the driver. The officer will ask innocently if he can check the driver's eyes without telling the driver that he is in fact administering a field sobriety test. Ultimately, a driver has the right to refuse any and all field sobriety tests, and jurors will interpret the officer's actions as being underhanded and unfair.

The NHSTS had indicated that nystagmus is not necessarily a product of intoxication and can in fact be attributed inner ear infections, brain tumors and brain damage. More likely than not, the officer will not take the time to see if the driver may have had any of these conditions. Nystagmus is attributable to many different factors, and it does not follow that intoxication must have been what caused the eye to bounce. A Wilson County DWI attorney can effectively cross-examine an officer on the HGN test and negate any inferences of intoxication.