Most people know that the legal limit for intoxication is .08. Even if you don't know what means, you know that if you take a blood or breath test and the results are over .08 you are going to get charged with DWI. Most people assume that the opposite of that is also true; if the result is under .08, they will let you go. Unfortunately, that's not always the case.
How can the police justify an arrest if the breath test result is under .08? The answer is based on several things. First, to be guilty of DWI, you must be intoxicated at the time of driving. It takes time to arrest you, take you to jail, and then give the test. Usually it's at least one hour, and more likely a couple of hours. Assuming you don't have anything to drink after you're arrested (I think that's a pretty safe assumption), your blood alcohol concentration should start going down at some point. The general rule is that it decreases .01 each hour. (that's an average, which can vary greatly - but that's the topic of a separate discussion). So if you're BAC at the jail is .09, and it's been roughly an hour since you were arrested, the police will assume you were .10 when you were driving.
This is where you can really hurt yourself by answering questions, because they police are going to believe you when you tell them when you had your last drink - even though they aren't going to believe you when you say you only had two beers. So how does this work. Let's say you're stopped at 10 p.m., and you tell the police you had a couple of beers, and the last one was around 8. That means you're blood alcohol concentration should be going down. They take you to the jail, and you agree to take the breath test, believing you are going to pass. The test is adminstered at midnight, and you blow .07. When they tell you the result you feel pretty good, until they tell you you're being arrested anyway. The rational is that your blood alcohol should have gone down by .02. so you were actually .09 at the time of driving.
That's only one scenario. The definition of inxoxication is having a blood alcohol concentration over .08, or not having the normal usue of your mental and physcial and mental faculties. So even without the test results, they could argue the field sobriety tests show you were intoxicated.
Mind blowing isn't it.
This is one situation where you definitely need to find an experienced lawyer, who undersands the concepts of "retrograde extrapolation", and how to point out the limitations in the state's theory. You also need a lawyer who understands the field sobriety tests, and is able to attack those.
If you've been arrested for DWI, and want to talk with us about your case, please give us a call.