Our high court here in Arizona has made some changes to the state's drunk-driving law. The law now seems, based on a reading of Howard Fischer's East Valley Tribune report, to allow people accused of DUI the ability to offer up physiological evidence.
This is the type of evidence referred to as "variables" - a person's body temperature at the time of the breath test, for example - which can call into question the accuracy of that breath test, either bumping the results up or pushing them down, depending on the situation.
If your guilt rests on whether or not your blood alcohol content is above that 0.08 limit, the results of the breath test the prosecutor is relying on to convict you had better be accurate. Or as accurate as possible. This is why the Arizona Supreme Court ruled the way it did. If your blood alcohol content falls inside no-man's land from 0.05 to 0.079, based on the breath test, you're not presumed to be drunk behind the wheel. So the variables matter.