Monday, December 3, 2012

"I Only Had One Drink!" Common Errors of Breathalyzers


A DWI can be one of the costliest arrests.  It’s costly on your wallet, your insurance, and your everyday life.  Like any scientific equipment, breath-analyzing machines are mechanical devices subject to error, if not maintained properly.  For individuals who drink responsibility and are under the legal limit, an error on a breath-analyzing machine could mean hefty fines and court costs, increased insurance rates, and the revocation of one’s driver’s license.  As states have legal limits, it is important for the breath-analyzing machines to be accurate to ensure everyone gets a fair evaluation.

Breath-analyzing machines are designed to read the amount of alcohol being released from your lungs, to determine how much alcohol remains in your blood.  There are common items that can cause a higher reading on the Breathalyzer, because they increase the amount of mouth alcohol, or alcohol that has not necessarily been ingested.  Items such as mouth sprays and wash often contain alcohol.  The use of these items immediately before taking a Breathalyzer increases the level of mouth alcohol and can produce a higher, but false, BAC reading.  Even a belch or burp can leave alcohol in the back of the throat and in the mouth, increasing the reading. 

Additionally, some health conditions such as diabetes are thought to increase the readings of BAC on breathalyzers.  Persons with diabetes can suffer from diabetic ketoacidosis, which causes the expulsion of acetones in the person’s breath.  As acetones are typically detected as alcohols by breath-analyzing machines, a person with diabetic ketoacidosis can register a higher, inaccurate BAC reading as well.  A similar effect has been found in individuals with a lower hematocrit levels.

With all the extraneous variables that factor in to the accuracy (or lack thereof) of breath-analyzing machines, it is imperative for the machines to be mechanically sound and operating properly.  As recently as March 2012, the mechanical inaccuracy of a breath-analyzing machine was the subject of a court case.  The San Francisco Police Department faced the embarrassment of having hundreds and possibly thousands of DWI arrests thrown out entirely.  Why?  The SFPD had a schedule established whereby an officer was calendared every ten (10) days to test the breath-analyzing machines and ensure their accuracy; however, the SFPD officers had not performed the tests for six years, leaving the assumed accuracy of the breath-analyzing machines in doubt.

Nearly every Breathalyzer on the market--whether professional or otherwise--comes with a manual indicating the unit is calibrated when it leaves the manufacturer and will remain accurate for six to twelve months--but requires re-calibration.  Once re-calibration is necessary, the Breathalyzer can give varied, unusually high or low, or no readings at all.  Couple the mechanical fallacy of the Breathalyzer with the other possible factors, and an individual can be wrongly charged and convicted of a DUI.

In short, if the breath-analyzing machine is not calibrated and verified regularly, any of the unknown variables that could be present--from mouthwash to the physical health of the driver--can lead to an inaccurate, and possibly higher, BAC reading. These small errors add up to a big problem for drivers and officers alike.  Think twice before you choose to blow, and stand your ground when you know you are beneath the legal limit.   

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