Dallas DWI Lawyer Blog | Attorney

In most DWI breath test cases, the State will attempt to convince the jury to find a person guilty based on a failed breath test.  In every one of these cases the State will use a breath test that was given some time after the arrest was made. 

It is important to remember that officers DO NOT HAVE scientifically valid breath test machines in their vehicles when they make an arrest for DWI.  Instead, the officer must transport the citizen accused of DWI to what is known as the "intoxilyzer room" which is usually located in a city or county jail.  The length of time between an arrest on the side of the road and a breath test score that is given in an intoxilyzer room is an important factor in EVERY DWI breath test prosecution.

The law requires that the state must prove a person was intoxicated AT THE TIME OF DRIVING, not 30 minutes, one hour or in many cases even longer when he or she gives a breath test at a jail facility.  In order to relate a failed breath test back to the time of driving, a State's expert must use what is known as Retrograde Extrapolation.

Retrograde Extrapolation is the scientific process used to take the score of a breath test and then back it up in time to show what a person's BAC was when they were driving.  However, in order to properly calculate usuing retrograde extrapolation the State's expert needs to know the following information:

1. The person's gender;
2. Their weight;
3. The time they had their first drink;
4. The time they had their last drink;
5. The time of the stop (arrest);
6. The type of alcoholic beverage consumed;
7. The type of  food a person ate and when they last ate;
8. The time the breath test was given;
9. The result of the breath test.

Often time, the state does not have all of the information for their expert to properly retrograde a breath test result to the time of driving.  In these cases a successful argument can be made by the defense attorney that the State did not satisfy its burden of proving that the citizen accused was intoxicated at the time they were operation a motor vehicle, and therefore, they should be found NOT GUILTY of driving while intoxicated.

It is important to do a thorough review of the police report and video of a DWI investigation to determine if the State will have problems with retrograde extrapolation in a DWI breath test case.  This is one of the most successful defensive arguments and can, in some cases, lead to a not guilty verdict.

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Did you know that those new braces, veneers, bridge or even cap may cause you to fail a breath test?  It is true!

Dental appliances can be a major factor in high breath test results. Like GERD defenses, dental issues concern mouth alcohol. If a person fails a breath test, and has had major dental work, this defense should be explored.

Dental appliances include, but are not limited to: braces, retainers, mouth expanders, bridges and false teeth or dentures. These appliances provide an opportunity for food to become trapped in the mouth after eating. Anyone who has had extensive dental work, such as braces, will tell you that getting food trapped in their teeth is a persistent problem.

When food is trapped within the teeth and alcohol is consumed, portions of the alcohol may become trapped in the teeth or dental appliance. Upon taking a breath test, breath is blown back through the mouth and alcohol molecules can be picked up by the expired breath before introduction into the machine. When this occurs, a false positive test for alcohol may be obtained.

Some studies have demonstrated that some dental adhesives can trap alcohol in ones mouth for up to one hour. A 15-20 minute waiting period before a breath test can be administered does not eliminate this problem.

There has been insufficient testing on subject who had both consumed and absorbed alcohol in their system with certain dental appliances to truly know the magnitude of the effect of the dental appliance. Therefore, a dental appliance problem can escape detection by the traditional slope detector on the machine. A “disconnect defense” may be available for a defendant who has dental issues, a high breath test and a “sober” video.

Note: The above article also appears in our Collin County DWI Blog.

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Does a citizen have an obligation to give a breath or blood test if asked by an officer during a DWI investigation?  To answer this question, an explanation of the "Implied Consent Law" in Texas is needed.  Below, please find an article from out Plano DWI Law blog detailing the Texas Implied Consent Law.

Texas Implied Consent Law.  By Dallas DWI Lawyer Troy P. Burleson

As I have reported in multiples posts, local counties are experimenting with mandatory blood tests from citizens suspected of DWI who refuse a breath test. These mandatory blood draws are likely to be challenged on state and United States constitutional grounds. As counties increasingly use this overly invasive tactic (forcible inserting a needle into citizens' veins), challenges to these policies are sure to follow.

However, a review of the Texas Transportation Code reveals that a citizen does have a right to refuse a breath or blood test. Below are three relevant sections from chapter 724 of the Texas Transportation Code which controls the law and procedures for blood and breath testing in Texas:

1) Implied Consent Law:

Most citizens do not know that as a condition of being issued a Texas driver’s license, they gave “implied consent” that they would submit to a breath or blood test if asked to do so by a police officer. Here is the Implied Consent law:

§ 724.011. CONSENT TO TAKING OF SPECIMEN. (a) If a
person is arrested for an offense arising out of acts alleged to
have been committed while the person was operating a motor vehicle
in a public place, or a watercraft, while intoxicated, or an offense
under Section 106.041, Alcoholic Beverage Code, the person is
deemed to have consented, subject to this chapter, to submit to the
taking of one or more specimens of the person's breath or blood for
analysis to determine the alcohol concentration or the presence in
the person's body of a controlled substance, drug, dangerous drug,
or other substance.
(b) A person arrested for an offense described by Subsection
(a) may consent to submit to the taking of any other type of
specimen to determine the person's alcohol concentration.

Acts 1995, 74th Leg., ch. 165, § 1, eff. Sept. 1, 1995. Amended
by Acts 1997, 75th Leg., ch. 1013, § 32, eff. Sept. 1, 1997.

2) Your Right to Withdraw your Implied Consent and Refuse a Breath or Blood Test:

Although you gave implied consent to submit to a breath or blood test when you received your driver’s license, the Transportation Code allows you to WITHDRAW your implied consent and refuse a breath or blood test. Below is the relevant section from the Texas Transportation Code:

>§ 724.013. PROHIBITION ON TAKING SPECIMEN IF PERSON
REFUSES; EXCEPTION. Except as provided by Section 724.012(b), a
specimen may not be taken if a person refuses to submit to the
taking of a specimen designated by a peace officer.

Acts 1995, 74th Leg., ch. 165, § 1, eff. Sept. 1, 1995.

This section of the Transportation Code clearly states that a

“specimen may not be taken”

if a citizen refuses to submit to the test. Therefore, according to the Transportation Code, you have an ABSOLUTE RIGHT to refuse a blood or breath test.

As indicated in 724.013 of the code, there are some exceptions that prohibit a person from refusing a blood or breath sample. Below are the exceptions from Section 724.012(b) of the Texas Transportation Code:

EXCEPTION:
(b) A peace officer shall require the taking of a specimen
of the person's breath or blood if:
(1) the officer arrests the person for an offense
under Chapter 49, Penal Code, involving the operation of a motor
vehicle or a watercraft;
(2) the person was the operator of a motor vehicle or a
watercraft involved in an accident that the officer reasonably
believes occurred as a result of the offense;
(3) at the time of the arrest the officer reasonably
believes that as a direct result of the accident:
(A) any individual has died or will die; or
(B) an individual other than the person has
suffered serious bodily injury; and
(4) the person refuses the officer's request to submit
to the taking of a specimen voluntarily.

Conclusion:

I am having a hard time understanding the stance of certain district attorneys and counties who seem to believe a citizen does not have a right to refuse a blood or breath test. It seems clear that unless you are 1) involved in an accident, 2) in which an individual has died, will die or suffered serious bodily injury, and 3) you are arrested for DWI then you do have a right to refuse a blood or breath test result (See the above sections from chapter 724 of the Texas Transportation Code). Therefore, I believe it is only a matter of time before these mandatory blood test policies are challenged in the Texas appeals courts.

Currently, the law allows a police officer to obtain a warrant from a judge or magistrate and obtain your blood. As reported, many local prosecutors and district attorneys believe that citizens do not have a right to refuse a scientific test, such as breath or blood.

3) Exceptions to your Right to Refuse a blood or breath test:

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