Frequently Asked Questions

Breath, Blood, and BAC Questions

Do I have to give a breath or blood sample if I am pulled over? What if the officer gets a warrant?
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The simple answer is that you are allowed to refuse a breath or blood sample. However, if you refuse, an officer can then apply for a warrant to get a sample of your blood. If the officer obtains a warrant, he or she can take a sample of your blood without your consent- and use reasonable force to do so if necessary.

In Texas, when we get a driver’s license, we are giving our “implied consent” that we will provide a specimen of our breath or blood if we are pulled over. However, we are able to revoke our consent. Revoking your consent would then mandate an officer get a warrant to take your blood.

Should I give a breath or a blood sample?
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This is always a tough question to answer. In most situations, it is better to refuse a breath or blood sample, and require the officer to get a warrant. I will go through some of the potential benefits of refusal below.

First, some smaller counties do not always have a judge or magistrate on call 24 hours to sign a blood warrant. In this case, if you refused the breath/ blood test, the officer would not be able to get a sample, and there would be no blood alcohol evidence in your case.

Second, the warrant itself can give rise to several issues in DWI cases. To get a search warrant, a police officer must provide a probable cause affidavit alleging the details of why he stopped you, any signs or clues of intoxication that lead him to believe you were driving while intoxicated, and that he believes by refusing the test you are attempting to hide evidence of intoxication. When the probable cause affidavit does not have the proper information, or if the search warrant is not executed correctly, an experienced DWI attorney can get the blood thrown out of evidence. Again, in this circumstance there would be no blood alcohol level in your case.

Also, there are more ways to get blood thrown out of evidence than there are for breath. To have a proper admissible breath test, fewer things have to happen and less people are usually involved in the process. Therefore, there is a lesser chance of human error.

In a breath test case, often there are only one or two officers involved with the stop, arrest and breath test process. Then there is a technical supervisor who makes sure the breath test machine is working properly.

In a blood case, you usually have the officer who stopped/arrested you, the judge who signs your warrant, the nurse who takes your blood, the officer who transports it to the lab, the person who receives the blood and stores it, and the analyst who prepares the sample and tests the blood. Thus, there is a greater chance of human error every step of the way.

There has been some debate amongst attorneys about breath versus blood. Some attorneys argue that when the breath or blood test cannot be thrown out, and will be coming into evidence, juries tend to distrust a breath sample more than a blood sample.

Either way, you want to hire an experienced DWI attorney who knows how to fight your case, regardless if there is a breath test, blood test, or no BAC in your case. You want an attorney who has the legal knowledge to get breath and blood results thrown out of evidence, and who can also successfully argue a case to a jury with the BAC in evidence.

Call Cannon Law today to book your free consultation.

If my BAC is above a .08 am I automatically guilty of DWI?
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No. Just because the breath or blood sample is alleged to be .08 or above, does not mean you are automatically guilty of a DWI.

The state is required to prove their case beyond a reasonable doubt. Therefore, the state must prove that the test result in your case is accurate and reliable beyond a reasonable doubt.

Hiring an experienced DWI attorney is important to help explain to a jury the multitude of problems commonly seen in breath and blood results. It is important that your attorney has a deep understanding of the instruments the police agency uses in breath test cases, as well as the science of gas chromatography and lab's standard operating procedures in blood test cases.

When your attorney can accurately explain these complex sciences in simple terms, juries often do not feel the state can prove the breath test or blood test was accurate or reliable beyond a reasonable doubt.

If my BAC is below a .08 will my case be automatically dismissed?
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Not necessarily. It would seem almost common sense that the district attorney’s office would dismiss your case if your breath or blood was under the legal limit. However, I’ve seen prosecutor’s refuse to dismiss the case out right for a few reasons.

The first reason being that the prosecutor believes they can prove one of the other definitions of intoxication. (See definitions of legal intoxication here). The prosecutor in this case after watching your video and seeing the Standard Field Sobriety tests, thinks they can prove to a jury that you lost the normal use of your mental or physical faculties due to the introduction of alcohol or drugs.

The second reason your case might not be dismissed out right is because the prosecutor will argue that even though your BAC was under the legal limit when the officer took your breath/ blood sample, your BAC was higher at the time of driving. Just because you had alcohol earlier in time, it does not mean that your BAC was always higher earlier in time. It takes time (30 min up to 2 hours) for the body to absorb alcohol; your BAC will be rising during this phase. Then your body starts eliminating the alcohol, and your BAC will begin to decline.

If a prosecutor has certain information, they will try to do what is known as retrograde extrapolation. This is a calculation based on certain information that you gave the officer to calculate what your BAC was at the time you were driving.

Finally, some prosecutors will not dismiss your case outright when there is a combination of drugs and alcohol in your body. Even if you might be under the legal limit for alcohol, and only have prescriptions in your system, some prosecutors will try to argue that you were intoxicated because of the combination of the two substances.

Are breath and blood tests always accurate?
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NO! I could write pages upon pages of all of the problems with breath and blood testing. Problems with breath and blood tests, when successfully argued, are thrown out of evidence all of the time. These can be due to both human and machine error.

To keep it simple, you need to hire an attorney who dedicates their practice to DWI; your attorney should have the proper education and training on how to find these issues in your case and successfully argue them to the prosecutor, judge, or jury.

What if I only had prescription drugs in my system to which I was legally prescribed by my doctor?
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The state can still charge you with Driving While Intoxicated, even if the drugs in your system are legally prescribed to you. The prosecutor will have to prove that not only you had the drugs in your system, but also that they were affecting you at the time you were driving.

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