What is the DUI defense of rising blood alcohol?
Rising blood alcohol is the concept that when we consume alcohol, it takes a period of time to absorb into our blood stream and that time can be anywhere from 20 minutes to several hours, depending on numerous variables. What that means for example is if I drink enough alcohol to get me to a .12 Blood Alcohol Content (BAC), which is well over the legal limit, I'm not going to drink that alcohol and instantly be at a .12. I'm going to become a .01, .02, .04, .08, .09 until I rise to the level of being a .12. Often, people get pulled over for Driving Under the Influence (DUI) when they're leaving a bar, leaving a restaurant, or leaving a party. They've recently finished drinking and their BAC is still rising, but they are still absorbing their alcohol. So, for example they may get pulled over and it may be 45 minutes until they get to the police station and they take their breath test. When they take their breath test, there may be a reading of .12, but when they're actually behind the wheel they may have been a .06, because they were still absorbing their alcohol. What's important is that for legal purposes what counts is what was their BAC when they were actually behind the wheel and the subsequent reading, an hour later, 45 minutes later, is only significant in that it allows us to try to draw an inference as to what their BAC was when they were driving. So many times people may have a blood test or breath test that comes up well above the legal limit. But when we extrapolate backwards and figure out what their BAC was at the time of driving, usually we have a range in which it may have reasonably been at the time of driving, and as long as the lower end of that range is below the legal limit, then they're not guilty. For example, the range might be .06 to .10, well the lower end of that is below the .08 threshold, and so they're not guilty.
