What Does It Mean There Is A Variance In The Breathalyzer Machine's Readings?
When you hear that the Breathalyzer or its equivalent has a variance in its readings, it means that the readings it produces are not absolutely exact. In fact, the readings are really a function of how the alcohol bi-products of metabolism interact with certain chemicals in the machine. As a result of those interactions, the fluid or other medium changes color and a photovoltaic measuring device changes its readings. As a result of all those things happening, a reading shows up on the machine as a percentage of blood alcohol. What it really is represents a function of a percentage of blood alcohol in the person's blood who is being tested. The machine supposedly extrapolates the amount of alcohol in the blood without any consideration of the size of the person, their prior experience with drinking alcohol, their gender or anything else. As a result, there are many reasons the breath test results don't accurately reflect the true amount of alcohol in a driver's blood. Also, there is no way to determine what amount would impair one driver's abilities, while have little or no effect upon another's. As a result, a good trial lawyer can often show to a jury all the reasons the driver should be found not guilty by reason of a reasonable doubt.