Rising Alcohol DUI Defense


Your DUI defense attorney might be able to demonstrate that at the time of the DUI blood or breath testing your Blood Alcohol Content (BAC) was rising and, therefore, your BAC was below the legal limit at the time of driving.  This defense is based on the fact that the BAC level never stays the same; generally speaking, it is either falling or rising at any given time.  Consequently, your BAC at the time your DUI test was taken was inevitably different than at the time of driving.  Whether you were driving under the influence is determined by the BAC at the time of driving.

If it can be shown that that your BAC level was rising, it can be shown that the BAC level at the time of driving was lower than at the time of driving.  It is possible, therefore, that at the time of driving your BAC was below the legal limit of 0.08 percent, even if the test shows a level above the legal limit.

If you were to draw a graph of how your BAC levels behave over time, initially, the line would slope upward reaching a curved peak and then fall in a downward slope.  Your BAC begins to rise as soon as you begin to consume alcohol because it takes a certain amount of time, longer than it takes you to drink, for your system to absorb the alcohol into your bloodstream.  As your system absorbs the alcohol your BAC reading gets higher until it reaches its peak absorption rate.  After the consumption has ended and the peak absorption rate is reached, the BAC will then begin to fall as your system starts to burn off the alcohol.

If your BAC level was rising (you were “on the rise” so to speak) your BAC was almost certainly higher at the time of the DUI test as compared with your BAC at the time of driving.  Depending upon the passage of time from the driving time to the time of the DUI test, the difference between your BAC levels at these two points in time can be significant and has the potential of resulting in dramatic differences.  For example, the delay from the time of driving to the time of the DUI test of, let’s say one hour or so, can produce a difference between BAC of 0.07 and 0.09 percent or higher, for example.  Such a difference could mean the difference between being below or above the legal limit and would be absolutely critical to your DUI case.

Your rising BAC DUI defense will most certainly require your DUI defense attorney to retain a forensic alcohol expert to establish the science and the facts necessary to defend you both at the DMV and in the DUI criminal court.  The expert will be necessary to interpret and explain the test results and to provide the appropriate scientific modeling and extrapolations showing that your BAC level was rising and, consequently, that you were below the legal DUI limit at the time of driving.  A good expert will be absolutely necessary to show, through scientific retrograde extrapolation techniques, that you were still in the alcohol absorption stage when you were tested.

Also, an excellent forensic alcohol expert will be necessary in order to interpret other facts relating to your DUI case, such as the pattern of your drinking, food consumption or your performance on the Field Sobriety Tests (FSTs).  For example, if your performance on the FSTs can be shown as deteriorating with time, this fact can be used to show increasing physical impairment as proof of your rising BAC.

We realize that the information related to the rising BAC defense is difficult, if not absolutely impossible, to apply proactively as a guide on how to behave during a DUI stop.  It is virtually impossible to self-assess when your BAC level is rising or falling, particularly because you might be impaired by the alcohol and not at your best with respect to your sense of time and ability to judge your own condition.  That said, it is fairly safe to say that your BAC is almost certainly rising if you were drinking recently.  Thus, if you were stopped and detained for a DUI investigation right after you had a shot of whiskey or two, your DUI test will certainly be higher than your BAC at the time of your driving.  This fact could be critical to the ability of your DUI defense lawyer to defend your DUI case successfully.

One factor that could be critical to the viability of your rising BAC DUI defense is the Preliminary Alcohol Screening (PAS) DUI test.  The PAS is the DUI breathalyzer-style test that you have been asked to submit to at the time of the DUI road stop.  It is a voluntary test designed to assist the DUI investigating officer in determining whether there is a probable cause to arrest you.  In contrast to the mandatory DUI chemical test – whether a DUI blood or breath test conducted after your arrest at the police station or at a hospital – you are not legally required to submit to the PAS test.  However, in certain situations, the result of the PAS DUI test might help you in establishing the fact that you were “on the rise” if the PAS shows a lower BAC level than the subsequent mandatory DUI test.  If your PAS test result is lower than the chemical test, this will show that your level of alcohol was rising.  Consequently, by using scientific extrapolation, the PAS DUI test can help you and you DUI defense attorney show that your BAC level at the time of driving was lower than at the time either the PAS DUI or the chemical DUI test were taken.

While advising you that the voluntary PAS DUI test might help you establish a rising BAC defense, we would like to caution you strongly to exercise extreme care when making the decision whether to take this test.  First of all, while the results of the PAS DUI can help your defense under certain circumstances, the results can often hurt your DUI case.  This is because the PAS DUI test result can be used against you as an additional piece of evidence if the result turns out to be unfavorable by showing that you were at or above the legal limit of 0.08 percent BAC at the time of testing and time of driving.  One certain piece of advice we can give you is to decline to take the PAS DUI test when you know you are above the legal limit.  If you take the PAS DUI test and the test shows that your BAC level was rising, in a situation when you are drunk and BAC level is high, no amount of scientific modeling and extrapolation will be able to show that your BAC level at the time of driving was below the legal limit.

It is hard if not impossible to offer a universal, fail-proof advice with respect to the PAS DUI test.  However, if we were compelled to offer you the safest and most simple possible rule with respect to when it might be advantageous for you to take the PAS DUI test, we would advise you to take this test only if your entire consumption of alcohol consisted of no more than one or two drinks and your drinking was very recent, i.e., taking place no more than 30 minutes before your test.  In such a situation, there is a significant likelihood that the PAS DUI test would turn out to be lower that the chemical DUI blood or breath test or, even better, produce a result of less than 0.08 percent of alcohol in which case the test could prove to be exonerating and perhaps even to convince the officer not to charge you with a DUI and let you go with or without a citation for something other than a DUI.

If you decide to decline to submit to the PAS DUI test, you must exercise a great deal of caution in how you choose to communicate your decision to the officer investigating your DUI case.  This is because the officer might interpret your refusal as a refusal to submit not only to the PAS DUI test, but also to the DUI chemical breath or blood test which you are legally obligated to take.  In our experience we have encountered many cases where the officer erroneously and unjustifiably has interpreted refusal to take the PAS as a refusal to take any test.  Often, the officers are too eager to conclude there was a complete refusal.  They might do so because the are not diligent enough in asking proper questions and investigating the DUI case thoroughly, or they might do so out of punitive vindictiveness because they know that refusal to submit to all tests will most likely result in more serious consequences, such as increased periods of license suspension or additional penalties such as jail time.

Be careful if you decide to refuse the PAS DUI test.  Make sure you are communicating unambiguously and very clearly that your refusal is limited to the PAS DUI test only and that you are ready and willing to submit to the chemical DUI blood or breath test as directed by the officer.  Preferably, you should communicate your intentions and willingness to cooperate and fulfill your legal obligations in the presence of as many additional witnesses as possible, even if such additional witnesses are other officers.  Witnesses can be critical in the event the DUI investigating officer is tempted to lie in his police report and state that you have refused all tests, counting that in all likelihood his word will prevail over yours.

For information regarding additional facts and consequences of refusing to submit to the chemical DUI test, please refer to the DUI Test Refusal section of our website.