Beating Positive Breathalyzer Results: Why Breathalyzer Tests Can Be Wrong

 We all know that drinking and driving is never a good idea.  There is no excuse for getting drunk and getting behind the wheel of a car.  However, what if you only had one drink or a sip of alcohol, even none at all, and you tested positive on a breathalyzer test?  This type of thing happens more than you think.  Recently in San Francisco over 1,000 false positive readings were thrown out, and prosecutions overturned because of such results. 

How can Breathalyzers Yield False Positive Results? 

1.        Improper Breathalyzer Calibration

Improper calibration was the main cause of the over 1,000 conviction turnovers in San Francisco last spring.  Every make and model is different, and law enforcement divisions must follow the equipment manufacturer’s guidelines for calibration exactly for the results to be accurate.  In the California incident, the 20 breathalyzer units were supposed to be calibrated every two weeks.  However, San Francisco law enforcement failed to maintain the equipment manufacturer’s guidelines and was forced to overturn hundreds of convictions based on the outcome of the breathalyzer test results.

2.        Alcohol Residue in Mouth

This may sound silly, but a breathalyzer is designed to measure the amount of alcohol saturation from the air in a person’s lungs.  The human body releases alcohol through the lungs as a way of processing and expelling it.  If a person has just taken a sip of alcohol, they will have residual alcohol in their mouths that the breathalyzer assumes is from the lungs.  This can yield a much higher reading than the actual amount of alcohol in the person’s body. Therefore, each breathalyzer recommends that the testing officer wait a certain period of time (usually about 20 minutes) before administering the test for accurate results.  If you have just downed half a glass of wine before getting pulled over, the residual alcohol in your mouth will mislead the breathalyzer into thinking you just drank an entire bottle.

3.        Breathalyzer Interference

Many things can cause false positive readings on breathalyzer tests, the most common being an elevated number of ketones in diabetics’ blood that causes an increase in acetone in their breath.  Some breathalyzer tests are sensitive to acetone and mistakenly register it as alcohol.  Other substances can cause false positive results as well such as paint fumes, chemical fumes, mouthwash, gum, cough syrup, and even herbal supplements. 

4.        Other Breathalyzer Reading Errors

A breathalyzer can also improperly measure BAC during the absorption phase of alcohol consumption. Absorption time varies depending on the person, but it can last anywhere from half an hour to two hours.  In the absorption period, alcohol is not evenly distributed through the blood stream and can yield erroneous breathalyzer results. 

Did You Test Positive for Alcohol on a Breathalyzer Test?

If you tested positive on a breathalyzer test you need to contact a DWI lawyer immediately to start building your defense.  Only an experienced DWI lawyer will have the knowledge and expertise necessary to fight for you in court.  If you are facing DWI or DUI charges after testing positive on a breathalyzer test, hire a DWI  or DUI lawyer today. 




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Should Houston Juries Know Margins of Error in Breath Testing?

A hearing was held to determine what evidence is required to be presented regarding breath tests in DWI cases in Washington.  At issue, whether the State should be required to produce for the DWI defense team and jurors the margin of error in breath testing procedures.  In other words, should the jurors in a DWI case with a breath test be given information about the breath test and the inherent errors in the breath testing machine?

Ted Vosk, the attorney for the DWI suspect, merely says, "All we’re asking is that this information be given to defendants and to the jury.”  Vosk is not arguing that the test should be thrown out all together.  However, he is arguing that the jurors should be given all information regarding the test. 

He goes on to say, "If prosecutors are going to use these tests as evidence, they should be required to show the jury the full picture."

To most of us citizens, this sounds pretty reasonable.  If the government is trying to convict a citizen of DWI (or any other crime for that matter), don't you think it makes sense that they have to provide everything to the defense?  I don't think that many would want their government to hide evidence in DWI cases - maybe I'm wrong.

So what did the government say?  Prosecutors argue that the law doesn’t require them to provide an uncertainty calculation for each test. State legislators already have established the hurdles that must be cleared for prosecutors to introduce test results as evidence — a move to clarify drunken-driving law. The margin of error is not among the criteria, Snohomish County deputy prosecutor Elise Deschenes said.  Jurors should be allowed to hear the results even if the margin of error isn’t calculated. It is up to the defense attorneys to attack the results, she said.

“It’s just one more way that the defense attorneys are trying to keep out the breath tests,” Deschenes said.

It seems like the prosecutors in this case don't really care about the fairness of the process or the potential for convicting an innocent person.  How about some independent thought from the prosecutor?  How hard would it be to tell the Court, "Judge, we have so much confidence in this breath test machine that we are happy to turn over the margins of error - we can win even with this evidence being presented?"  I would have gained a great deal of respect for the prosecutor if he had done just that.  But instead, the prosecutor tries to avoid being forced to turn it over. 

I would hope the prosecutors here in Houston would have the guts to take a different stand on this issue than the prosecutors in this case.  Do you think Houston juries should have all the evidence about the breath test?  Share your thoughts.

Why has it taken Harris County so long to tell us they won't oppose a new trial for those cases with fake breath tests?

Deetrice Wallace, the technical supervisor responsible for maintaining the integrity of the breath test machines used by law enforcement to convict arrestees of DWI, will be spending the next year behind bars for faking inspections on the breath test machines.

I have spoken to Ms. Wallace on many occasions over the past few years as we have obtained information about the breath testing machines that she inspected.  She seemed like a nice enough person and was always forthcoming with the information that we requested.  She even requested that the payments for the records go to a Boy Scout Troop.  I'm not sure what led her to fake the results of the tests, but it sure has had a huge impact on many DWI client's lives.

The real question that I have is why has it taken so long for Harris County to say that they will not oppose a new trial for those that were affected by the fake tests?  Galveston County sent me a list of my Galveston DWI clients that took a breath test where Deetrice Wallace had maintained the breathalyzer back on January 15, 2009.  Harris County still has not sent me a list of my clients that are affected by Deetrice Wallace.  We have had to re-create that list on our own.

What's in a name DPS?

I learned from my friend and fellow blogger Paul Kennedy that the Texas Department of Public Safety has officially changed its name for the breath alcohol testing program in Texas.  The new name - Texas Forensic Breath Alcohol Laboratory Service.  DPS also made another name change - the Technical Supervisor is now called a "Forensic Scientist."

So what else has changed in the program to warrant these changes?  Absolutely nothing.  You might wonder why they changed the name if nothing else in the program has changed.  My guess - they are trying to sound more "scientific" and therefore trying to give the program more credibility in court.

The breath testing program has had its fair share of problems.  Remember the Deetrice Wallace scandal? The HPD crime lab problems (the DWI breath testing program is part of the crime lab)?  It seems they are trying to put a new spin on an otherwise problematic department.

Toyota developing new technology for DWI and drunk driving

According to a yahoo article, Toyota is in the process of developing technology to combat drunk driving in commercial vehicles.  The device that they are currently testing would have a hand-held breathalyzer that detects alcohol in a persons breath and prevent the vehicle from being started if the level of alcohol is over a certain amount.   The article goes on to state that there will be a camera to verify the person that has blown into the machine.

Funny thing about this article is the technology already exists and is being used in DWI cases every day here in Houston.  The only difference is that the technology used here in Texas is "after market," not original to the vehicle.  Go see my friends at EZ Interlock if you are interested in the technology that is already on the market. 

The Harris County courts are using this technology more and more often.  My concern is that Big Brother is getting bigger and bigger.  I think it is very possible that Big Brother may mandate this type of technology for everyone at some point in our history, and that is just frightening.  What else is Big Brother going to mandate - that we all GPS technology in our vehicles so they can know where we are at all times?

Police Reading Form - Is it too much to ask?

Before requesting a breath sample or blood sample in a DWI case, an arresting officer is required to provide information about the consequences of the breath test.  Section 724.015 of the Texas Transportation Code requires the officer to inform a DWI suspect that his license can be suspended for 180 days if the person refused a breath test and that that refusal can be used against the person in court.

Lately, however, it seems the police have been asking "You going to give a breath test?"  When the client says "No", the police mark it as a refusal.  The cops seem to be getting lazy and not following the law.  I have heard this story far too many times lately for it not to be true.  This can be a reason to get a DWI case dismissed. 

It is a shame that the police are not required to video tape this admonishment.  In fact, it is a shame that everything the police do is not taped.  Through our investigations, we have found that some cops are just not to be trusted.  As Houston DWI Lawyers, we should not have to investigate the cops to see if they have the capability to video our clients.

Supreme Court confirms our right to confront witnesses

This week in the Melendez-Diaz decision, the United States Supreme Court confirmed and guaranteed our Sixth Amendment Constitutional right to confront witnesses. 

Melendez-Diaz was charged with possession of a cocaine.  At his trial, the government relied upon a sworn affidavit by a lab analyst to prove what the substance was, the amount of the substance and the quality of the substance.  The lab analyst was not called as a live witness and the affidavit was used to convict the defendant.  The Supreme Court overturned the conviction stating, the Defendant was entitled to "be confronted with" the persons giving this testimony at trial.

This decision could have far reaching implications for DWI defendants in Texas.  More and more often, we are seeing the government force DWI defendants to give blood pursuant to a search warrant.  Also, there are many cases where the government relies upon hospital blood draws as evidence in a Texas DWI case.  In Houston, Texas, the Harris County District Attorney's Office often relies upon the hospital records and a business records affidavit to prove the results of the blood alcohol test

The Melendez-Diaz decision insures, that in these DWI cases where the government is trying to introduce the results of a blood test, that we will have the right to demand the chemist appear in court and justify the results and be subject to cross examination.