Testing During the
Information courtesy of Lawrence Taylor - DUIblog
In previous posts, I have explained many of the reasons why breathalyzers are inaccurate and unreliable. See, for example, "Breathalyzers -- and Why They Don't Work"; "Warning: Breathalyzer in Use"; "Convicting the 'Average' DUI Suspect"; "Why Breathalyzers Don't Measure Alcohol"; "Driving Under the Influence of... Gasoline?; "How to Fool the Breathalyzer". (These and many other sources of error are explained more fully in Chapter 6 of my book, Drunk Driving Defense, 5th edition.)
One of the most common sources of error in breath alcohol analysis is simply testing the subject too early -- while his or her body is still absorbing the alcohol.
Let's take a common example. At a restaurant Sarah shares a bottle of wine with a friend. She nurses one glass over a one-hour dinner. Nearing the end, another glass is poured from the bottle and she finishes this. The two friends then order an after-dinner drink. Noting the time, Sarah quickly finishes the drink and leaves. She is stopped by the police one block from the restaurant. After questioning and field sobriety tests, she is taken to a police station and tested on a breathalyzer. The machine shows her blood alcohol concentration (BAC) to be .09% -- over the legal limit. She is booked for DUI and jailed.
Sarah's true BAC, however, was much lower. If a blood sample had been taken instead of a breath test, the results would have shown only .05% -- well under the legal limit.
Absorption of alcohol continues for anywhere from 45 minutes to two hours after drinking or even longer. Peak absorption normally occurs within an hour; this can range from as little as 15 minutes to as much as two-and-a-half hours. The presence of food in the stomach can delay this to as much as four hours, with two hours being common.
During this absorptive phase, the distribution of alcohol throughout the body is not uniform; uniformity of distribution -- called equilibrium -- will not occur until