The Legal Defense of ‘Rising BAC’ in Florida DUI Cases

Arrested With a High BAC? Your BAC May Have Been Lower While You Were Driving — Here’s How We Defend You

When a Florida DUI arrest happens, people often assume the results of the breath or blood test tell the full story. They don’t. One of the most overlooked defenses in DUI cases is what’s known as the “rising BAC” defense. I’ve used it to protect clients across Florida who were arrested after a night out but weren’t actually over the legal limit when they were behind the wheel.

Blood alcohol concentration (BAC) is not static. Alcohol takes time to absorb into your bloodstream, which means your BAC can increase even after you’ve stopped drinking — and, more importantly, after you’ve stopped driving. If your BAC was below 0.08% while you were driving, you are not guilty of DUI under Florida law, no matter what the results of a breath test taken later might say.

Let me break this down clearly and show you why having a private criminal defense attorney matters in cases involving rising BAC.

How Alcohol Absorption Works in DUI Defense

After you consume alcohol, it moves from your stomach into your small intestine, where it gets absorbed into the bloodstream. This process takes time. Depending on several factors — like your weight, what you’ve eaten, how fast you drank, and the type of alcohol — your BAC can continue rising for 30 to 90 minutes after your last drink.

That time lag is the key to this defense. If you were pulled over and tested 30 minutes later, the result doesn’t reflect your BAC at the time of driving. This is where I come in. We work with toxicologists who can retroactively calculate your BAC at the time you were actually behind the wheel. If we can demonstrate that your BAC was under the legal limit while you were driving, Florida law says you are not guilty of DUI.

Florida DUI Law and Rising BAC

Florida Statute § 316.193 defines DUI as being in actual physical control of a vehicle while either:

• Under the influence of alcoholic beverages to the extent your normal faculties are impaired, or

• Having a BAC of 0.08% or higher.

The second part is critical. The BAC must be 0.08% or higher at the time of driving — not when you're tested later at the station.

Florida Statute § 316.193(1)(b): “A person is guilty of the offense of driving under the influence... if the person has a blood-alcohol level of 0.08 or more grams of alcohol per 100 milliliters of blood… while driving or in actual physical control of a vehicle.”

This distinction gives us the opportunity to argue that your BAC rose after the traffic stop. It requires time-sensitive analysis, expert testimony, and someone who understands how to raise reasonable doubt in front of a judge or jury.

Public defenders are often overloaded and may not be able to bring in experts to run a retrograde extrapolation — that’s the scientific method used to estimate what your BAC was at an earlier time. As your private attorney, I ensure that we build a defense backed by science, not just assumptions.

Real Case Example: Client Acquitted Based on Rising BAC

One of my clients was pulled over after leaving a dinner party in Naples. He’d had two glasses of wine over the course of 90 minutes and then took a shot of whiskey just before heading out. He was stopped three minutes after pulling out of the driveway. Officers noted glassy eyes and the smell of alcohol. He declined roadside tests but later agreed to a breath test, which showed a BAC of 0.10%.

The State filed DUI charges based on the breath result. But I knew from his timeline and physical condition that we had a strong rising BAC defense.

We hired a forensic toxicologist who reviewed the evidence, including receipts, timing of the drinks, his weight, and the breath test time. The expert calculated that his BAC was below 0.08% while he was driving but rose above the limit by the time the breath test was administered 38 minutes later.

At trial, we presented this evidence. The jury returned a not guilty verdict in under 45 minutes.

The State had the breath test on their side, but we had the science and the truth. This win would not have happened without the investment in expert analysis and private defense.

Common Defenses That Pair With Rising BAC

The rising BAC defense is often used alongside other DUI defenses, including:

Improper Breath Test Administration:
Officers must follow strict procedures for breath tests. If they fail to observe you continuously for 20 minutes or don’t properly calibrate the machine, the result may be inadmissible. We use that to challenge the prosecution’s main evidence.

Violation of Your Rights During the Stop:
If the officer lacked probable cause for the traffic stop or detained you without legal justification, we file a motion to suppress all evidence that came after — including any BAC tests.

Lack of Physical Impairment:
Even if your BAC is questionable, Florida law requires proof of impairment. If your driving was lawful, your speech was clear, and your coordination was steady, we argue that you weren’t impaired under the first part of the DUI statute.

A public defender may not have the bandwidth to build a layered defense. With private counsel, we attack the case from every angle.

Why Timing Is Everything in Rising BAC Cases

The difference between a .07% BAC and a .10% BAC might only be 20 minutes. Prosecutors won’t tell you that. But we will.

Every minute between your last drink and your test matters. That’s why I collect every detail — when you drank, how much you ate, what time you were pulled over, when the test was administered, and even the brand of alcohol consumed. These aren’t random facts, they are the building blocks of your defense.

We’ve had clients avoid license suspension, criminal records, and jail because we built a case around this very argument. But it requires immediate investigation. Video footage, witness statements, bar receipts, and body cam evidence can disappear quickly. The sooner you hire a private defense attorney, the sooner we can preserve what could save your case.

Why You Need a Private DUI Defense Lawyer

Public defenders are dedicated and often skilled, but they carry large caseloads and limited resources. In a rising BAC defense, timing, science, and expert testimony can make or break your case. It’s not enough to point out that your BAC was high — we must prove when it got that way.

As a private attorney, I retain forensic experts. I subpoena time-stamped surveillance footage. I interview bartenders. I track cell phone records and GPS. I challenge test results, file suppression motions, and bring science to the courtroom. I do all of this because you deserve a fair fight — and that requires resources.

Musca Law, P.A. has a team of experienced criminal defense attorneys dedicated to defending people charged with a criminal or traffic offense. We are available 24/7/365 at 1-888-484-5057 for your FREE consultation. We have 30 office locations in Florida and serve all counties in Florida.

DUI Defense Frequently Asked Questions (FAQs)

What is the ‘rising BAC’ defense in a Florida DUI case?
The “rising BAC” defense argues that your blood alcohol level was under the legal limit while you were driving but increased afterward, reaching 0.08% or more only by the time the breath or blood test was performed. This defense hinges on how alcohol absorbs into the bloodstream and can be critical in getting DUI charges dismissed or reduced.

Can I still be convicted of DUI if I was below 0.08% while driving?
Yes, if prosecutors can prove your normal faculties were impaired even below 0.08%. But if the charge is based solely on BAC, then being below 0.08% while driving means you're not guilty under Florida Statute § 316.193(1)(b). That’s why we fight hard to show what your BAC was at the actual time of driving.

How do you prove rising BAC in court?
We work with toxicology experts who perform a retrograde extrapolation. They calculate backward from your test result to estimate your BAC at the time of driving, using variables like your weight, alcohol intake, and time passed. Their findings are presented at trial to raise reasonable doubt.

What happens if my breath test result is over 0.08% but I wasn’t drunk while driving?
If your BAC was still rising when you were stopped, the test result may not reflect your condition while you were behind the wheel. That’s the foundation of the rising BAC defense. We combine this argument with evidence of sober behavior to challenge the entire case.

How long does alcohol take to affect your BAC after drinking?
It can take 30 to 90 minutes for alcohol to peak in your bloodstream after consumption. If you had a drink right before driving or being stopped, your BAC could rise significantly between the time you were pulled over and the time the test was administered.

Is it worth hiring a private attorney for a first DUI in Florida?
Absolutely. Even a first DUI can have long-term consequences — criminal record, license suspension, and high insurance rates. A private attorney can build a custom defense and pursue every angle, including rising BAC, which may be overlooked otherwise.

Does the timing of my breath test matter in a DUI case?
Yes, it matters a great deal. The longer the delay between driving and testing, the more likely your BAC changed. We request exact test times and compare them with traffic stop logs to build a rising BAC argument that holds up in court.

Can eating before drinking affect my BAC?
Yes. Food slows alcohol absorption, which can delay your BAC from peaking. That can be an important factor in showing that your BAC was lower at the time of driving. We investigate what and when you ate to support your defense.

Is retrograde extrapolation accepted in Florida courts?
It is, provided it’s conducted by a qualified expert and based on reliable data. We use certified forensic toxicologists who are experienced in testifying in Florida DUI cases. Their analysis can introduce critical doubt about the accuracy of the prosecution’s timeline.

What should I do immediately after being charged with DUI in Florida?
Contact a DUI defense lawyer right away. The clock starts ticking on administrative license suspension and evidence collection. A private lawyer can start your defense immediately, preserving evidence and identifying key facts that could lead to dismissal or reduced charges.

Contact Musca Law 24/7/365 at 1-888-484-5057 For Your FREE Consultation

Musca Law, P.A. has a team of experienced criminal defense attorneys dedicated to defending people charged with a criminal or traffic offense. We are available 24/7/365 at 1-888-484-5057 for your FREE consultation. We have 30 office locations in Florida and serve all counties in Florida.