Saturday, April 13, 2024

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What Are Breathalyzers, How Do They Work…and Are They Accurate?

California DUI AttorneyDid you ever wonder how breathalyzers work? There is a website which will give you a pretty fair idea. But first, let’s clear up some confusion….

There are many different kinds of “breathalyzers” — or, more accurately, there are many kinds of breath testing devices. The first of the modern breath testers, manufactured by Smith and Wesson many years ago (yes, that Smith and Wesson), was called the Breathalyzer. Since then, various manufacturers have recognized the growing market and come out with their own models, bearing such names as IntoxilyzerIntoximeter,  DataMaster and so on; most of these products have been produced in different model versions, such as the Intoxilyer 4011, 5000 and 8000.

To deal with the confusion, the term “breathalyzer” came to be used as a generic term for any breath testing instrument. (To confuse things further, a German company — Draeger — bought the rights to the Breathalyzer brand and have sometimes used that name in some of their models.)

Most of these are evidentiary machines — that is, larger machines generally kept at the police station whose test results are used in evidence. Others are smaller, handheld units carried by officers in the field; generally called PBTs (preliminary breath tests) or PAS (preliminary alcohol screening), these are less accurate and are usually used as a field sobriety test to help determine whether to arrest a suspect.

The original Breathalyzer operated using a wet chemical method of analysis, employing a disposable glass ampoule of chemicals. Although still occasionally found in law enforcement, this primitive technology was replaced in later machines largely by infrared spectroscopy or, mainly in handheld units, fuel cell analysis; a couple of the more recent machines use a combination of infrared and fuel cell.

Now that this has been cleared up, you might want to visit the following sites to understand the actual workings of these gizmos:

Chemical (the Breathalyzer)
Infrared spectroscopy (the Intoxilyzer)
Fuel cell (the Alcosensor)

As for the accuracy of these machines….To further understand why these machines aren’t nearly as accurate as law enforcement would have you believe, visit a few of my previous posts on my personal blogsite, DUIblog:

Breathalyzers — and Why They Don’t Work
Breathalyzer Inaccuracy: Testing During the Absorptive Stage
Breathalyzer Inaccuracy: Post-Absorptive
Breathalyzer Inaccuracy….It Gets Worse
“Close Enough for Government Work”
Why Breathalyzers Don’t Measure Alcohol
How to Fool the Breathalyzer
Breathalyzers and Radio Frequency Interference
Breathalyzers: Why Aren’t They Warranted to Measure Alcohol?

If you need to speak to a Southern California DUI defense attorney, call The Law Offices of Lawrence Taylor at 562.989.4774.  With offices located in Los Angeles, Orange, Riverside and North San Diego counties, the firm has limited its practice to DUI defense exclusively since 1979.

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Lawrence Taylor

Lawrence Taylor

Lawrence Taylor is one of the most respected DUI defense attorneys in the country. With over 43 years experience in DUI defense, he has lectured to attorneys at over 200 seminars in 41 states. An original founder and former Dean of the National College for DUI Defense, Mr. Taylor's book "Drunk Driving Defense" has been the best-selling textbook on the subject for 31 years and is now in its 7th edition. He is today one of only 5 DUI attorneys in California who is Board-certified as a DUI defense specialist. A former Marine and graduate of the University of California at Berkeley (1966) and the UCLA School of Law (1969), Lawrence Eric Taylor served as deputy public defender and deputy district attorney in Los Angeles before entering private practice. He was the trial judge's legal advisor in People vs Charles Manson, was Supreme Court counsel in the Onion Field murder case and was retained by the Attorney General of Montana as an independent Special Prosecutor to conduct a one-year grand jury probe of governmental corruption. Turning to teaching, Mr. Taylor served on the faculty of Gonzaga University School of Law, where he was voted Professor of the Year, was invited to be Visiting Professor at Pepperdine University Law School, and was finally appointed Fulbright Professor of Law at Osaka University in Japan. Mr. Taylor continues to limit the practice of his 5-attorney Southern California law firm to DUI defense exclusively. With offices in Long Beach, Irvine, Beverly Hills, Pasadena, Riverside and Carlsbad, Mr. Taylor and his firm of DUI defense attorneys may be reached through their website at or by telephone at (800) 777-3349.

2 Responses

  1. Very nice post. I just stumbled upon your weblog and wished to say that I have truly enjoyed surfing around your blog posts. After all I will be subscribing to your feed and I hope you write again very soon!

  2. I think in any DUI having an attroney is essential. If this is your first offense an attroney may be able to help you get the case plead down to a non DUI offense. I am an attroney in Ohio and can often get first time offenders tickets plead down to a lesser non DUI offense.An attroney can also negotiate with the prosecutor on your suspension and other punishments. They can also help you obtain driving privileges. A good attroney will be familar with the judges/prosecutors attitudes and what they normally do in DUI cases. This helps to protect your criminal and BMV record. In Ohio the look back period for DUI’s is 6 years and up to 20 in some cases. I don’t know the law in California but you don’t want to just plead guilty and get another DUI in 10 years and have it come back to bite you b/c you didn’t do all you could to protect yourself the first time. You could also plead not guilty and attend the pre trial with the prosecutor yourself. But again you won’t be as familar with how the court handles DUI’s as an attroney. At the very least it never hurts to set up an office visit and get an attroney’s opinion.

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