Calculating BAC

Understanding Blood Alcohol Concentration (BAC)

Blood Alcohol Concentration (BAC) is a key measure of the amount of alcohol in your bloodstream. Whether you’re preparing to drive home after a night out or find yourself in a situation involving Driving Under the Influence (DUI), knowing your BAC is essential. If stopped for a DUI, you might be asked to take field sobriety tests like standing on one leg, following a light with your eyes, or walking a straight line heel-to-toe. If these tests raise suspicion of impairment, additional testing with a breathalyzer or chemical tests (blood or urine) may be required.

What is Blood Alcohol Concentration?

BAC indicates the level of alcohol in your blood, increasing as you consume alcoholic drinks. In most states, including Pennsylvania, the legal BAC limit for adults is 0.08 percent. Exceeding this threshold can lead to DUI charges. A BAC of 0.08 means there are 0.08 grams of alcohol per 100 ml of blood. For those under the legal drinking age, Pennsylvania enforces a zero-tolerance policy. This means a BAC of 0.02 percent or higher results in an automatic DUI charge.

Factors Influencing BAC

• Gender: Women generally reach a higher BAC than men after consuming the same amount of alcohol, largely due to differences in body size.
• Body Fat: Individuals with a higher body fat percentage may have a higher BAC since fat tissues absorb less alcohol compared to other tissues.
• Empty Stomach: Drinking on an empty stomach can result in a higher BAC. Food slows down the absorption of alcohol, leading to a lower BAC.
• Body Size: Smaller individuals often have a higher BAC than larger ones because there is less body mass to distribute the alcohol.

Estimating BAC

To estimate your BAC, consider the alcohol content in different beverages. Typically, one drink equals a 5-ounce glass of wine, a 1.5-ounce shot of liquor, or a 12-ounce beer. Wine usually has 15-20% alcohol, liquor 30-50%, and beer about 4-4.5%. For example, a Long Island Iced Tea, containing five types of alcohol, has an alcohol content of around 22%.

To calculate BAC, you need the drinking time, the volume of alcohol consumed, the beverages’ alcohol percentages, and your weight. Widmark’s Formula is useful here:

\[ \text{BAC} = \left( \frac{\text{ounces of alcohol consumed} \times 5.14}{\text{weight in pounds} \times \text{gender constant}} \right) – 0.015 \times \text{hours since drinking began} \]

For gender constants, use 0.66 for women and 0.73 for men.

Example Calculation

Consider a 150-pound adult woman who drank two 12-ounce beers over the past two hours:

\[ \% \text{BAC} = \left( \frac{1.20 \times 5.14}{150 \times 0.66} \right) – 0.015 \times 2 \]

\[ \% \text{BAC} = \left( \frac{6.168}{99} \right) – 0.03 \]

\[ \% \text{BAC} = 0.062 – 0.03 \]

\[ \% \text{BAC} = 0.032 \]

This result is below the adult legal limit of 0.08%, indicating that she is not legally intoxicated.

Actions to Take if Your BAC is Too High

It’s critical to comply with BAC testing requirements. Refusal results in an automatic license suspension and additional charges. If arrested for DUI, it’s wise to contact an experienced Greensburg DUI attorney immediately. The Logue Law Group has successfully handled numerous DUI cases across Greensburg, West Virginia, and Ohio. Reach out for a consultation at 844.PITT.DUI or (844) 748-8384, or visit our website to connect with us.