Understanding BAC & Impairment

How Much Can You Drink Before Being Intoxicated?

One of the most important things to understand about DUI arrests is that field sobriety tests and chemical tests are not foolproof. Although chemical tests may give a concrete number to an individual's blood alcohol concentration (BAC) level, that number does not directly correlate with an individual's level of intoxication or impairment.

The Massachusetts DUI attorney at The Law Offices of Joseph D. Bernard P.C. knows that there is more to BAC than the legal limit of .08%, and you should as well—if you have been arrested for DUI/OUI, knowledge of BAC and impairment may aid you in your defense against the DUI charge.

What Is Blood Alcohol Concentration?

BAC is the amount of alcohol present in a person's body at a given time. Members of law enforcement often measure BAC with a chemical test, which can be conducted via breath, blood, or urine. In any case, these tests are not as precise as you may think—although they are able to measure the presence of chemicals in the body, these tests may not accurately differentiate between types of alcohol.

How is Alcohol Absorbed?

Alcohol is generally ingested by way of the mouth. It travels to the stomach where it is held until the brain identifies the stomach's contents to determine if digestion is needed. Alcohol does not require digestion and can be released immediately. If consumed with food, the body will hold the alcohol in the stomach with the food until the food has been properly digested for nutritional absorption. Once released from the stomach into the small intestines, the alcohol is readily absorbed into the bloodstream and carried throughout the body.

Alcohol will be deposited in various organs in proportion with the organ's water content. The brain has a very high water content. Hence, there will be a lot of alcohol deposited into the brain. Additionally, alcohol, as a "slightly soluble gas," will be deposited into the lungs, where it can be exchanged between the blood and the breath.

How is My BAC Determined?

The blood breath ratio is used as a conversion factor to translate the amount of ethanol (alcohol) in a breath sample into a quantitative blood alcohol concentration. The blood breath ratio, based on Henry's Law, is a ratio of the amount of alcohol in the blood and the amount of alcohol in the breath. Henry's Law predicts how gasses will dissolve in the alveoli and bloodstream during gas exchange. Essentially, the amount of molecules of a volatile substance (i.e. alcohol) in a liquid (i.e. blood) will be represented by a proportional amount of the same molecules in the air immediately "above" the liquid (i.e. in the lung). In any given volume of liquid there will be a much greater concentration of molecules than in the same volume of the air above. The generally accepted ratio of 2100:1 is programmed into the breath testing device and used to calculate BAC, which is then used as the evidence to arrest and charge an individual with OUI. However, simple differences in body temperature (such as having a fever) or breathing patterns (such as holding one's breath or brief hyperventilation) can produce inaccurate BAC readings.

What are Interfering Substances?

Interfering substances are substances other than ethanol that may interfere with the breath sample. The Draeger Alcotest 9510 machine utilized in Massachusetts uses two types of technology to obtain an alcohol measurement - Infrared Spectroscopy (IR) and Electric chemical fuel cell oxidation (EC). The IR reads the alcohol measurement while the EC is used to verify the IR reading and detect interfering substances. There are specific limits on how closely the results of the two tests must be in order for the results to be considered valid. Experimentation indicates that some chemicals, other than ethanol, could be measured and reported without triggering the EC's interferent detection system. Some examples of potential interferents include 1-Butanol (n-butanol, butyl alcohol), which is a natural product of fermentation present in foods and beverages, and Butyl Acetate, found in fruits and synthetic fruit flavorings.

Does BAC Determine My Level of Intoxication?

At best, a chemical BAC test may only offer speculation as to an individual's level of intoxication. BAC tests may not account for many of the situational and biological factors in a situation. Differences in body height, weight, metabolism, and other factors play an essential role in how an individual processes alcohol, but this is accounted for in the results of a BAC test. When it comes to a DUI charge, these factors may play a vital role in your defense. The Massachusetts DUI lawyer at The Law Offices of Joseph D. Bernard P.C. understands how important it is to take these factors into account when preparing a defense for the firm's clients.

Protect Your Rights & Driving Privileges in Court

It is very possible that you were arrested for DUI/OUI without being impaired or showing visible signs of intoxication. There are many situations where the evidence against individuals arrested for DUI are weak. Unfortunately, without an effective defense against these charges, misconstrued evidence and improper police procedure can still result in a DUI conviction.

If you are facing DUI/OUI charges or the penalties of a conviction, get in touch with an OUI attorney in Massachusetts at The Law Offices of Joseph D. Bernard P.C. immediately. With nearly 20 years of experience in DUI and criminal law, the legal team has tried over 200 cases and secured countless successes. The firm is committed to finding positive solutions to their clients' legal issues.

Our firm is led by a former prosecutor with working knowledge of the law and the tactics that may be used against you in court. Schedule your free consultation and learn how The Law Offices of Joseph D. Bernard P.C. can help you!