In a surprising twist to a recent local news story:
2nd DUI test shows chief's daughter under limit
A second test following the arrest of (name removed to protect the alleged guilty and also so she won't find this in case she googles herself), daughter of the Scottsdale police chief, showed her blood-alcohol content was 0.072 percent, just below Arizona's 0.080 percent presumed level of intoxication....
Now that doesn't mean they won't charge her, but being the daughter of a police chief, they probably won't charge her.
Both tests could be correct. You would have to know what she drank and when she started and stopped to extrapolate back to what her BAC (blood alcohol content) was at the time of driving.
Your BAC looks like a bell curve, well kind of. If you are on the declining side, the second test could be lower than the first and both would be right. Lots of folks are on the rise when they are arrested (it takes awhile for alcohol to be absorbed in your system so when you stop drinking your BAC rises for a while before gradually declining). For them the 20 minute wait for the test would put them higher than at the time of driving or if there are 2 tests, the second test is higher.
But if she stopped drinking for awhile before she drove, then did the mandatory 20 minute wait before the test, enough time could have passed that the second test was lower than the first. It's all a question of timing and absorption rates.
But even though science says you could have a test higher than the time of driving, most states have passed laws that have a presumption that what the test says is what you were at the time of driving. No basis in science...but that doesn't stand in the way of a legislature
Good heavens, I haven't done DWI cases in years, not sure where that came from