DUI Defenses at Different BAC Levels

My blood alcohol level (or BAC) was 0.08…is that high? My test results were .16 or .24…is that high? When someone first hears a BAC, or blood alcohol content level, they may not really know what to think.

A BAC, or blood alcohol content, is somewhat like your temperature; at 98.6 you are “normal”, at 101 you are definitely sick, but at 103 you need medical help. Normally, a person who has a BAC of .04 is presumed sober; but, in the eyes of the law, a person who is at a .08 is considered impaired.

The truth is, most people don’t know what someone looks like at a specific BAC. The following is a rough guide of how different BAC levels would typically affect an individual:

  • 0.10% - Relaxed, lowered inhibitions, and maybe slight physical impairment
  • 0.15% - Judgment and reaction time are impaired, with physical control problems
  • 0.20% - Significant physical impairment
  • 0.30% - Passed out

Defending a DUI with a Low BAC level

So how do you defend a DUI with a low BAC level? There are many ways; including two common ways known as (1) a “rising” BAC and (2) the “range of accuracy” on the testing equipment.

Rising BAC

First, a rising BAC is when the alcohol level in the body is higher at the time of the chemical test than it was at the time of driving. This happens because the alcohol level in the body does not stay the same, but first goes up and then goes down. When the person drinks alcohol, the body takes time to absorb it. During this time, they are said to be “rising” or having a rising BAC.

If a person is “rising” the BAC is going up over time. So, if the chemical test is taken 30 minutes after you were stopped, the BAC result would be higher than it was AT THE TIME OF DRIVING. The prosecution must prove that you were over the legal limit AT THE TIME OF DRIVING, not 30 minutes after driving (when you would have been home in bed if the cops did not stop you).

Rising BAC is scientific fact. However, each case is unique…and how this would apply in an individual situation depends on the facts of the case.

Equipment Inaccuracies

Second, low BAC cases can be defended by looking at the accuracy of the equipment. No testing equipment is perfect; and most experts will agree that a result from a machine can be different from the actual alcohol level in the person. How much the reported BAC can differ from the actual or true BAC depends on the expert and the equipment used; but it could easily be a difference of .02. So, a BAC measured to be a 0.08 could truly be .06… that is REASONABLE DOUBT, that is NOT GUILTY.

Defending a DUI with a high BAC level

High BAC DUI’s can also be defended with the same defenses as low-level BAC cases. But, they also have many other possible defenses.

The chemical testing machines can give faulty high-test results. There are things that interfere with the normal operating of the equipment and cause the results in a test, or all of the tests, to look like they are much higher than they should be.

Breath testing equipment can be interfered with by radio frequencies, chemicals in the room, or even a person’s medical condition. Blood testing equipment can be interfered with by improper handling of the blood sample, improper cleaning of the testing equipment, or the wrong amount of testing chemicals.

When interference happens (or may have happened), the test results are unreliable. When a test result is unreliable, there is reasonable doubt that the result is correct.

Of course, in either breath or blood testing cases, if the proper procedures were not used to get the sample in the first place the end result or BAC is not reliable. Not reliable is REASONABLE DOUBT, and that means the person is NOT GUILTY.


A skilled and experienced DUI defense attorney will be able to investigate a case, find the errors and mistakes made by the cops or the crime lab, and put together a strong defense.

Regardless of a high or low the BAC result is, everybody is entitled to a vigorous defense. Many times, people just accept what they are told. However, when a complete investigation is done, it is surprising to discover how often innocent people are arrested for driving under the influence.

Regardless of alcohol level, one accused of such a serious crime as a DUI should have their case reviewed by a knowledgeable DUI defense attorney.

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