Blowing It: Just How Accurate are Breathalizers?

by Ladyblogger on September 19, 2012

(U.S. law) The ability to measure the alcohol content in a person’s breath is the main weapon that law enforcement officials have in combating driving under the influence (DUI). Police officers are able to do this with roadside tests called breathalyzers. These machines have a long history of use, but like most technologies, they are not foolproof. Breathalyzers have been known to be inaccurate on a widespread basis, and it is only when a person fully understands the specifics of these machines that they can fight an unwarranted DUI charge.



The first successful attempt at a breathalyzer test was reported in a 1927 research paper that showed alcohol was detectable in a football after an inebriated person inflated the ball by blowing it up. Breathalyzers have since become far more technological. Police officers now use breathalyzers with either infrared or electrochemical technologies. Many breathalyzers are large machines that are kept at police stations or mobile ‘drunk tanks’, but police officers also have handheld versions of these devices. Unfortunately, these breathalyzers are manmade and mechanical in nature, which means that malfunctions or incorrect readings are a very real possibility.

Inaccurate Breathalyzer Results


Any New Jersey dwi lawyer could provide a number of distinct reasons that a breathalyzer may not be reliable, but Philadelphia police made national news when they discovered one of these reasons had affected several DUI cases. In 2011, Philadelphia police discovered that some of their breathalyzers were not properly calibrated. This means that any results garnered from the affected machines wouldn’t be accurate. This incorrect calibration could’ve affected over one thousand DUI cases, and each of these cases had to be reviewed by the state. These inaccurate results cost Philadelphia an excessive amount of time, manpower and money to review. It was fortunate that the mistake was caught at all. This error likely cost several innocent people their licenses and even careers. Breathalyzers must be periodically calibrated to ensure that they are working correctly, but there are also several other instances where the machine’s reading may not be completely accurate.

Reasons for Incorrect Breathalyzer Results


A machine being improperly calibrated is obviously one big reason that breathalyzers can be inaccurate, but there are other times when it can be incorrect even when it has been properly maintained and cared for. Many breathalyzers, for instance, can mistake acetone for the ethyl alcohol that it is testing for. This can be detrimental to diabetics and dieters who often have levels of acetone in their bodies that are hundreds of times higher than the average person. Breathalyzers can also make incorrect assumptions based on a person’s ‘mouth alcohol’. This is alcohol that remains in a person’s mouth after drinking, and thus never has a chance to be absorbed into their system. These machines will attribute the alcohol concentration of what remains in the mouth to the air from a person’s lungs, which is what is supposed to be tested. These examples prove that along with not being calibrated, breathalyzers can show false positives for a great number of people.

The breathalyzer is an effective and useful weapon for the government’s fight against drunk driving. It is capable of simply using a person’s breath to estimate their actual blood alcohol content; which can usually only be definitively discovered by a blood test. Unfortunately, these machines have proven time and again that they can be fooled, and this is usually to the detriment of the person pulled over for suspicion of drunk driving. Experienced attorneys know all of the reasons a breathalyzer may produce inaccurate results, so it is important for a person to consult with one if they are ever accused of a DUI.

Anthony Joseph writes on various legal subjects, and is a contributing author for Evan M. Levow. He is a New Jersey dwi lawyer who is nationally recognized for his efforts and success. Mr. Levow’s law firm is the only one in the state of New Jersey to own both, the Breathalyzer and the Alcotest machines, which are used for breath testing in New Jersey.

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