Most people assume a DUI case comes down to a single number on a breathalyzer. Under Florida law, that’s only one of two entirely separate ways the state can prove the same charge — and the other one doesn’t require a chemical test result at all.
Florida DUI Law Has Three Prongs, Not One
Florida Statute 316.193(1) defines DUI three separate ways, and the state only has to prove one of them:
- Impairment — the person was “under the influence of alcoholic beverages, any chemical substance… or any substance controlled under chapter 893, when affected to the extent that the person’s normal faculties are impaired”
- A blood-alcohol level of 0.08 or more grams per 100 milliliters of blood
- A breath-alcohol level of 0.08 or more grams per 210 liters of breath
The second and third are what’s often called “per se” DUI — if the number is there, that’s legally sufficient by itself. Whether the person seemed impaired, drove erratically, or passed every field sobriety exercise doesn’t change the outcome once that threshold is met. The first prong is different: it’s not about a number at all, it’s about whether the person’s normal faculties were actually diminished, and it’s the one that gets used when there’s no valid chemical test result — because the driver refused testing, the test was thrown out, or no test was administered.
“Normal Faculties” Has an Actual Legal Definition
This isn’t a vague, common-sense term left up to a jury’s intuition — it’s defined precisely in Florida’s Standard Jury Instructions, the official language juries are read in every DUI trial: “Normal faculties include but are not limited to the ability to see, hear, walk, talk, judge distances, drive an automobile, make judgments, act in emergencies and, in general, to normally perform the many mental and physical acts of our daily lives.”
“Impaired” has its own defined meaning too, and it’s worth being precise about: the instructions define it as “diminished in some material respect” — not intoxicated, not drunk, not high. Diminished. That’s a meaningfully lower bar than what most people picture when they hear “impaired,” which is exactly why this prong of the law exists as a real, usable path to conviction independent of any chemical test.
Proving This Without a Breath Test
When there’s no valid chemical result to point to, the state builds its case entirely from what the arresting officer observed, testified to, and formed an opinion about at the scene. That typically includes: the driving pattern that led to the stop, what happened during the stop itself, face-to-face contact with the driver, how the driver exited the vehicle, behavior at the roadside, performance on field sobriety exercises, and — notably — a refusal to take a requested test, which can itself become evidence the state points to.
None of this requires scientific measurement. It’s built from an officer’s direct observations and their trained opinion, which is exactly why this prong of a DUI case often comes down to the credibility and specificity of that officer’s account rather than a number that either clears a threshold or doesn’t.
Why the Distinction Actually Matters
Two elements have to be proven beyond a reasonable doubt for a normal-faculties DUI conviction: that the person was driving or in actual physical control of a vehicle (defined broadly — the person doesn’t have to have been actively driving at the moment of the stop, just physically in or on the vehicle with the capability to operate it), and that alcohol or a controlled substance had diminished their normal faculties to a material degree.
The practical takeaway is this: a DUI case doesn’t automatically fall apart because there’s no breath or blood test result in evidence. If you’re trying to understand what you’re actually facing, or evaluating what happened during a stop, the real question isn’t just “what was the number” — it’s which of these two legal theories the case is actually built on, because the evidence, and the way it gets challenged, is genuinely different depending on the answer.