Reflects Florida Statutes current through the 2026 session and reported Florida case law. Every statute and case cite links to the official text, which opens in a new window.
Florida officers are trained to run three tests at the roadside — walk-and-turn, one-leg stand, and Horizontal Gaze Nystagmus (HGN) — all developed by the same National Highway Traffic Safety Administration research program. In court, though, Florida treats HGN differently from the other two, and that difference can matter a great deal to how a case gets tried.
The lay-observation / scientific-evidence split
In State v. Meador, 674 So. 2d 826 (Fla. 4th DCA 1996), Florida’s Fourth District Court of Appeal drew a sharp line between the three standardized tests. Walk-and-turn and one-leg stand, the court held, are ordinary physical tasks — a juror can watch someone perform them and judge for themselves whether it looked right, the same way they could evaluate any other lay observation an officer testifies to. No special expertise is needed to get that testimony in front of a jury.
HGN is different. Because it asks an officer to interpret an involuntary physiological response — jerking eye movement most jurors have no everyday basis to evaluate — the court held HGN results are scientific evidence, not lay observation. That means an officer cannot simply testify “I saw nystagmus, so the defendant was impaired” and have it go to the jury unchallenged. The traditional predicate for scientific evidence has to be laid first: qualification of the person administering the test, and a foundation for the scientific basis of what the test measures.
What this means for a case
Practically, it gives a defense a specific, well-established point to raise that doesn’t exist for walk-and-turn or one-leg-stand results: if the state tries to introduce HGN results without first establishing the proper scientific predicate, that’s a basis to object to or move to exclude that evidence. The other two tests don’t get that protection — they go to the jury as ordinary officer testimony, for whatever a juror thinks it’s worth, foundation or no foundation.
For the general rundown on all three standardized tests, which ones are and aren’t validated by NHTSA, and what refusing any of them actually does under Florida’s implied consent law, see DUI Florida’s breakdown of field sobriety testing.