Blood Alcohol Content (BAC) in DUI Cases

Defense from Our Jacksonville DUI Attorney

In order to have an objective test of DUI, legislators across the country (including Florida) have adopted laws that define having a blood alcohol content (BAC) of or over 0.08 percent as creating a presumption of drunk driving. BAC can be tested by the use of breath tests, blood tests and urine tests. The most common method by far is the breath test due to its ease of use and speed of result. However, as a Jacksonville DUI defense attorney can demonstrate in court, the breath test is subject to many errors in administration and is hardly a reliable test of BAC. Blood tests and urine tests as well have points of unreliability. If you are charged with a DUI based on high BAC, you are urged to seek legal help to defend your rights.

What is blood alcohol content?

As a cornerstone of many DUI cases, it is important to recognize what BAC is exactly. Essentially, BAC refers to the amount of alcohol that is in a person's blood at any given moment; this is the most common scientific measure of a person's level of intoxication. When someone states that a defendant had BAC of 0.10 percent, it means that there were 0.10 grams of alcohol per 100 grams of blood. BAC, however, will differ depending on the person. It can take different people different amounts of alcohol to reach the same BAC.

Factors such as time spent drinking, type of alcohol, body weight and more can all play into BAC. For example, if a 120 pound female drinks three glasses of wine in one hour, she will have an estimated BAC of 0.09 percent. If a 200 pound man drinks the same amount of wine over the same time frame, he may only have a BAC of 0.04 percent. This is just a hypothetical situation, but it does demonstrate how different factors can all affect differences in BAC. Regardless of how much it takes to reach a certain BAC level though, once a person reaches it, certain effects may be experienced.

Effects of alcohol at different BAC levels is explained below:

  • 0.010 – 0.029: Most individuals will appear normal.
  • 0.020 – 0.059: Most individuals will be relaxed, happy and talkative. Some will have difficulty concentrating on tasks.
  • 0.06 – 0.09: Most individuals will have decreased inhibitions and be more extroverted than normal. They may struggle with reasoning, as well as depth perception or their peripheral vision.
  • 0.10 – 0.19: Most individuals will begin to over-express themselves and may experience violent mood swings. They may struggle with their reflexes and reaction times, resulting in staggering and slurring their speech. They may also have problems with their motor control.

Breath Test: An Unreliable Test of BAC

If you take a breath test, it does not directly measure the concentration of alcohol in your blood. Rather, it tests the concentration of alcohol in your breath and then by a calculation estimates blood alcohol concentration. As there are many variables that can contribute to the alcohol present in your breath, the test often gives an incorrect answer. Below are a number of questions that an experienced attorney may ask as they work to build a comprehensive defense on your behalf:

  • Has the machine been recently calibrated?
  • Did the officer tell you to keep blowing?
  • Had you just finished drinking when you were stopped?
  • Did you burp or belch during the testing process?
  • Do you have a medical condition?
  • Was the breath test machine adjusted for the temperature?
  • Do you wear dentures, or have you recently had dental work?

Contact Us Today!

At The Law Offices of Jason K.S. Porter, P.A., you have the benefit of three former DUI prosecutors with over 90 years of combined legal experience. As former DUI prosecutors having used breath test to make our cases, we know intimately their points of unreliability. We also know how blood tests and urine tests can fail to show correct BAC. We use this knowledge and experience to defend our clients charged with DUI and are accomplished at obtaining dismissals and acquittal of charges.

No matter the exact charges you find yourself facing, we encourage you to contact us for a free initial consultation to discuss your defense.

Thousands Of Clients Helped

Hear What Some Of Them Have To Say

  • “Jason and his staff were very professional.”

    - Jeremy Taylor

  • “Glad We Picked Porter!”

    - Anonymous

  • “List of Blessings”

    - Barry McDaniel

  • “The best team ever.”

    - Jonathan Nestor

  • “You couldn't find a better lawyer anywhere.”

    - Ed W.

  • “Maureen Horkan is an amazing attorney who only had me and my best interests at heart!!”

    - Ellen Kushner

  • “Mr. Porter and his staff were wonderful.”

    - Calvin W.

  • “This firm is great!”

    - Gale B


    - Jocelyn

  • “The best attorneys you will find. I love you guys!”

    - Gale B

  • “I love this law firm...”

    - Nina Brown

  • “Very professional attorney!”

    - M.S.

  • “He is our family attorney forever.”

    - Anonymous

  • “Mr. Porter and his staff do an incredible job!”

    - N.B.

  • “Jason is the most diligent attorney”

    - C.

  • “Nicole Carlucci is an absolutely amazing attorney.”

    - Paul R.

  • “I would refer anyone to this firm”

    - Meagan venable

  • “Mr. Porter and his staff are fantastic.”

    - P.B.

  • “This Lady Knows the Law”

    - Michael

  • “Impressive Attorney’s very knowledgeable, able to fight for your rights always kind, handles conflict with ...”

    - Diane

  • “What an outstanding lawyer!”

    - Donna Graham

  • “The experience was just wonderful! We would recommend them 10 times over.”

    - Kizgel D.

  • “She was a Godsend! I highly recommend this firm!”

    - Angela Muhammad

  • “Maureen Horkan FIGHTS for you!”

    - Anne St. John

  • “Mr. Porter was so nice and explained everything in a way that I could understand.”

    - Elizabeth Eggemeyer

  • “Forever Grateful”

    - Robert Bloom

  • “He is a seasoned professional that is respected within the law community.”

    - Angie Osterland

  • “Compassionate Caring and Honest”


  • “Aggressive and Compassionate. Highly Recommend.”

    - Nikki

  • “Jason Porter excellent attorney”

    - John Parker

  • “Absolutely Amazing Attorneys!!!”

    - Judy S.

  • “This Legal Team is Wonderful!”

    - Diane and Richard

  • “My life is in a much better place today because of Jason's integrity within the community and relationships with the ...”

    - Josh C.

  • “When needed, you answered my questions clearly and politely.”

    - Anonymous

  • “Jason answered all my emails and phone calls.”

    - Anonymous

  • “Mr. Porter was very friendly and knowledgeable.”

    - John

  • “They turned my frown upside down!”

    - JJ

  • “Thanks for everything.”

    - Anonymous

  • “The Best I Could Imagine!!!”

    - Robyn Simrell

  • “He prepared our family through each and every step.”

    - Anonymous

  • “Jason Porter is superb.”

    - Tyron baker

  • “Jason is the best lawyer in Jacksonville.”

    - Carla B.

  • “I will never be able to thank Jason Porter enough.”

    - Michael Crane

View More Testimonials