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sjfcontrol wrote:There's something seriously wrong with the math on page II-17 of the manual.

Consider exactly what a BAC of 0.08 means. blood alcohol concentration is expressed in terms of the "number of grams of alcohol in every 100 milliliters of blood". When we find that a person has a BAC of 0.08, that means that there is one-eighth (0.08) of a gram of alcohol in any given 100 milliliter sample of blood. One-eighth of a gram is equal to one hundred milligrams (a milligram is one-thousandth of a gram). So, at a BAC of 0.08, the person has 100 milligrams of alcohol in every 100 milliliters of blood, or exactly one milligram per milliliter. If a person has a BAC of 0.08 it means there are 0.08 grams of pure ethanol in every 100 milliliter ("percent") of his/her blood.

Hmm, I agree with your math and not theirs. That is not the student manual I used since I went through it so long ago and I never caught that mistake. I will have to see if I can find a newer edition and check the math there to see if the error has been corrected.

But I have to say that if the math in the manual officers are taught from is not correct, I can see how it could cause someone to doubt the whole program.

I cannot get all of your data without a sign-on to your library. Using the Texas State library, I did look at the first report (the HGN review by Rubenzer and Stevenson). Recognizing my bias toward the police, I must say I think the article started from an anti-police or anti-SFST point of view. Several of the arguments in it were based on the presumption that the officer would change his scoring of clues on the HGN based on what the portable breathalyzer said. The authors note that the HGN was verified in testing but claim the test was incorrect because it compared HGN results solely to alcohol and not including other possible causes. They also note the SFST battery verification was a field test based on stopping people for poor driving and seeing if the test predicted intoxication properly. They claim this is flawed because of the selection bias of only stopping suspected drunks.

The problems with their claims are that if a cop is going to lie, no test is valid. I don't think it will happen but concede it is possible. The other two claims have flaws in logic that are similar. If I was testing HGN to use it as a diagnostic tool, they would be right. But if I am testing it to see if it predicts alcohol impairment, the tests seem valid to me. They acknowledge that officers are taught that there are other possible causes of HGN, and even of other instability problems for the other tests, but fail to acknowledge that the test has been validated for what the officers are attempting to do.

The test is used to help confirm the officer's prior suspicion that the person is intoxicated based on other factors present - like his driving mistakes. This is the key to the validity of the SFST, in my opinion. It is a factor used in conjunction with many other factors and it is never considered conclusive. It leads to the officer making an opinion based on his observations and training. The opinion may be confirmed later by a breathalyzer, or may not. If the breathalyzer does not confirm, the officer can give his opinion in court and the defendant can give their opinion and the jury can chose who they think is more accurate.

But, since you asked for reports of scientific testing, I thought you deserved more than just my opinion. In addition to advising you to check the article's references (he lists several validation studies), here is an older copy of the SFST instruction manual to read (how the tests are given and the officer's are taught): http://breathtest.wsp.wa.gov/SupportDoc ... 202004.pdf" onclick="window.open(this.href);return false;

And here is the NHTSA page on a report on how to manage training for SFSTs, including some of the verification of the tests:
http://www.nhtsa.gov/People/injury/alco ... uction.htm" onclick="window.open(this.href);return false;

There are several points in this thread that need to be looked at carefully. First, and most important, is the original question of intoxication. The Code Construction Act tells how to read any law in Texas. It says that if a word is not specifically defined for the section, then it has the common meaning unless there is a specific legal meaning attached already. Intoxication is not defined for the specific section on carrying, but is defined in both chapters 46 (46.06) and 49 of the Penal Code. The two definitions are not the same. While you could argue for the definition in Chapter 46, since it is weapon related, I think the court would take the definition in chapter 49. I say this because the word intoxicated has come, in common use, to have the specific legal meaning for driving while intoxicated. For almost all other meanings, the common use would say drunk or some similar slang term, not intoxicated.

Chapter 49 has a defined intoxicated as meeting either of two separate conditions. The first is the condition already quoted about loss of use of your faculties. The second is the specific case of having a blood alcohol content of .08 or higher. You are intoxicated if you meet either condition, so in at least one sense, there is a limit for carrying while intoxicated. The second limit is the loss of your faculties, which could be at either side of .08.

You do not have to take field sobriety tests. And yes, some are very subjective (the touch your nose, recite the alphabet, bend over, etc. that are sometimes seen on TV). But almost every officer in the country now uses what is called the Standardized Field Sobriety Tests and these are not subjective at all. There are three tests in this battery, and each has been repeatedly studied and tested in the laboratory. Each has a set probability of predicting true intoxication, meaning .08 BAC. Each has a set procedure for instructions and administering the tests and each has set rules for what counts as a clue of intoxication and how many clues are needed to "fail" the test. And, no matter what you do wrong, if it is not one of the specified clues, it cannot be counted against your performance.

While I have seen people who have problems with the one leg stand or the walk and turn when they are not intoxicated, I have not yet met someone who had problems with the horizontal gaze nystagmus test that way. I do know they can exist, I just have never seen one yet. I am pretty good with the HGN at detecting intoxication, but not nearly as good as some people I know. The officer who trained me in it could usually predict within two points (thousandths) what the breathalyzer would show.

It is correct and important to remember that intoxication does not necessarily mean alcohol. The law defines an intoxicant as ANY substance that can cause impairment. A lot of drugs, even prescription ones taken on a doctor's orders can cause intoxication.

And finally, (because I can't remember anything else I wanted to comment on though I think I missed something I noted when I read it), I want to agree with some of the advice posted. It is probably best if you do not carry after drinking at all or taking any drugs for any reason. But this is just my advice and it is certainly not the law.