When Is Expert Testimony Admissible in a Florida Vehicular or Vessel Homicide Case?

August 28, 2025 Don Pumphrey, Jr. Criminal Defense Social Share

In Florida, vehicular homicide (Fla. Stat. 782.071) and vessel homicide (Fla. Stat. 782.072) are very serious felony offenses. Both vehicular and vessel homicide are second-degree felonies, punishable by up to 15 years in prison and a $10,000 fine. They become a first-degree felony (up to 30 years in prison and a $10,000 fine) if either of the following is true:

• The defendant failed to stop, give information to authorities and/or render aid to the victim(s)
• The defendant has a prior conviction for vehicular homicide, vessel homicide, DUI manslaughter or BUI manslaughter (Trenton’s Law)

A key aspect of many vehicular and vessel homicide cases is the admission of expert testimony. An expert’s opinion regarding what occurred during a fatal collision that led to vehicular or vessel homicide charges against a defendant may sway a jury towards conviction or acquittal, depending on the testimony.

But there are key safeguards that exist in Florida that prohibit excessively speculative or unreliable expert testimony from being admitted in court. This is because doing so may mislead the jury and result in the handing down of an erroneous verdict. Florida’s courts use what is known as the Daubert standard to assess the admissibility of expert testimony (Fla. Stat. 90.702).

If someone is charged with vehicular or vessel homicide, the testimony of one or more experts is very likely. So, how do courts determine which expert testimony is permitted to be heard at trial and which testimony is insufficiently reliable or excessively speculative? This blog will answer that question.

Before discussing why expert testimony is so common in these cases, it is first important to understand the elements of vehicular homicide and vessel homicide in Florida.

For someone to be guilty of vehicular homicide in Florida, the State must prove all of the following beyond a reasonable doubt:

• The defendant was recklessly operating a motor vehicle (car, truck, motorcycle, van, etc.)

• The defendant’s reckless operation of the motor vehicle caused the death of a human being or unborn child at any stage of fetal development

Florida law defines a motor vehicle as “every device in, upon, or by which any person or property is or may be transported or drawn upon a highway, except devices used exclusively upon stationary rails or tracks.”

This does not include trains or trams, but it does include:

• Cars and trucks
• Motorcycles
• Golf carts or bicycles when operated on highways (Meister v. Fisher, 462 So. 2d 1071 (Fla. 1984))
• Mopeds 
• Vans
• Motor scooters
• Commercial vehicles and RVs

Vessel homicide has nearly identical elements, and requires proof of all of the following beyond a reasonable doubt:

• The defendant’s actions resulted in the death of a human being or unborn child
• The defendant was operating a vessel at the time (boat, airboat, one boat pulling another boat, etc.)
• The defendant operated the vessel in a reckless manner, which caused the death of the victim

For someone to be guilty of vessel homicide or vehicular homicide, the State does not have to establish beyond a reasonable doubt that the defendant intentionally killed anyone. This only requires a determination that the operator of the vehicle or vessel acted recklessly, causing the death of one or more victims.

Florida’s courts have held that speeding alone is insufficient to establish recklessness for purposes of a vehicular or vessel homicide conviction. However, excessive speed can serve as a factor, as courts evaluate recklessness based on the totality of the circumstances. State v. Gensler, 929 So.2d 27 (Fla. 3d. DCA 2006)

Historically, factors that Florida’s courts have considered in evaluating whether a defendant was reckless include:

• Whether the defendant was speeding, and if so, by how much
• Whether the defendant disregarded traffic signals/stop signs
• Time of day (or night)
• Whether visibility was poor
• Whether the roads were crowded or empty
• Whether a defendant was looking continuously at their cell phone for a long period of time (Andriotis v. State, 399 So.3d 1235 (Fla. 5th DCA 2025))

Courts have held that even if someone was not speeding at the time of a crash, a vehicular (or vessel) homicide conviction may still occur if the totality of the circumstances establish that the defendant was reckless (e.g. running stop signs, driving with eyes closed, etc.). McCreary v. State, 371 So.2d 1024 (Fla. 1979)

Note: Recklessness is established when someone operates a vehicle or vessel “in willful or wanton disregard for the safety of persons or property,” and with “a conscious and intentional indifference to consequences and with the knowledge that damage is likely to be done to persons or property.” Luzardo v. State, 147 So.3d 1083 (Fla. 3d. DCA 2014).

Because vehicular homicide and vessel homicide do not require intent to kill, expert testimony is frequently relied upon to determine whether someone’s actions were truly reckless, as opposed to simply careless (negligent). Expert testimony may also be useful in determining if a defendant even consciously contributed to the crash if the theory revolves around loss of control (e.g. brake malfunction, unconsciousness, etc.).

Florida’s courts apply the Daubert standard, first outlined by the U.S. Supreme Court in Daubert v. Merrell Dow Pharmaceuticals Inc., 509 U.S. 579 (1993), in determining if expert testimony is admissible in a vehicular or vessel homicide case. The purpose of this standard is to ensure that the expert analysis offered to a jury is potentially valuable, rather than unnecessarily confusing or misleading.

A key case on this issue is Kemp v. State. Kemp v. State, 280 So. 3d 81 (Fla. 4th DCA 2019). There, Kemp was convicted of five counts of vehicular homicide after his vehicle crashed into another and killed its five occupants. Kemp was traveling at nearly 130 miles per hour at the time of the crash.

Kemp argued he had gone unconscious at the time due to an unforeseeable medical episode and lost control of his car – which if true, would bar a conviction for vehicular homicide. Smith v. State, 218 So. 3d 996, 998 (Fla. 2d DCA 2017). At Kemp’s trial, the State admitted testimony from a law enforcement corporal (Dooley) who assisted in vehicular homicide investigations.

Dooley testified at Kemp’s trial that the “downward arc” of Kemp’s vehicle at the time of the collision indicated that Kemp was applying the brakes at the time of the crash – contradicting Kemp’s “unconsciousness” argument. The State heavily relied upon Dooley’s testimony during the remainder of the trial, including during closing arguments. Kemp was found guilty.

On appeal, the 4th District Court of Appeal reversed Kemp’s conviction. It found that Dooley’s testimony was inadmissible under Daubert.

The court observed that for expert testimony to be admitted, the following must be true: 

• The testimony is based upon sufficient facts or data
• The testimony is the product of reliable principles and methods
• The witness has applied the principles and methods reliably to the facts of the case

The court noted that the trial judge’s role is “to ensure that speculative, unreliable expert testimony does not reach the jury under the mantle of reliability that accompanies the appellation expert testimony.” Rink v. Cheminova, Inc., 400 F.3d 1286, 1291 (11th Cir. 2005). In Kemp’s case, Dooley’s testimony was considered too speculative and unreliable.

This is because by Dooley’s own admission, he essentially used an “eyeball test” while looking at the damaged vehicles to determine that Kemp’s car was curving downward (indicating Kemp was applying the brakes) at the time of the crash. The court held:

“The record does not show that Dooley’s technique—eyeballing the shape of the crash damage on a vehicle to determine if the vehicle that made the impact was braking—has been tested, has been subjected to peer review or publication, has a quantifiable rate of error, or is generally accepted in the field of accident reconstruction. Dooley’s repeated invocation of the magic words “training and experience” was insufficient, without more, to establish the reliability of his opinion under Daubert.”

The Kemp court provided a list of factors for courts to consider in admitting expert testimony in a vehicular (or vessel) homicide case. These include:

• Whether the theory of the witness can be or has been tested
• Whether the theory or technique has been subjected to peer review and publication
• The known or potential rate of error of a particular scientific technique, as well as the existence of standards controlling the technique’s operation
• General acceptance in the scientific community

If these factors cut in favor of admitting expert testimony (e.g. the methods/theories are tested, peer-reviewed, low error rates and are generally accepted), courts will be more likely to let it in. But if these factors cut against admitting the testimony, courts will generally exclude it. A court mistakenly allowing the jury to hear unreliable or excessively speculative “expert testimony” can constitute reversible error on appeal. 

This is why a deep understanding of Daubert and what courts consider in deciding to admit or exclude expert testimony is especially important in a vehicular or vessel homicide case. In some cases, a State or defense expert may sway the jury to find (or not find) recklessness sufficient to support a conviction.

Whether this testimony is offered at trial will depend on the theory of the expert and its scientific backing (or lack thereof). However, a Florida defense attorney’s deep understanding of Daubert in these cases can make a significant difference in the outcome, as the admission of favorable expert testimony (or exclusion of unfavorable testimony) may greatly influence the jury.

In certain cases, expert testimony may still not be admissible even if it satisfies the Daubert standard. If the probative value (tendency to prove or disprove a material fact) of the testimony is substantially outweighed by one or more of the following, it is inadmissible even if found to be sufficiently reliable (Fla. Stat. 90.403):

• Unfair prejudice 
• Misleading the jury
• Confusion of issues
• Needlessly cumulative presentation of evidence 

If the State plans to introduce expert testimony and the trial judge finds this qualifies under Daubert, the testimony may be objected to on any of the above grounds. However, the success of such an objection is heavily dependent on the facts of a case.

If someone is charged with vehicular homicide or vessel homicide, various defenses are available, one or more of which may apply depending on the facts of a case. These include:

• Lack of reckless operation
• Lack of causation (e.g. the alleged victim/another party was responsible for the crash)
• Constitutional and procedural defenses (e.g. suppressing post-Miranda statements or illegally obtained evidence)
• Unforeseeable medical emergency 
• Mechanical failure (e.g. faulty brake and the defendant had no notice)

In sum, expert testimony is admissible in vehicular and vessel homicide cases if the theories and methods used by the expert are sufficiently reliable. This must be the product of sufficient facts or data, reliable principles and methods, and the witness must apply those principles and methods reliably to the facts of the case. 

Though a finding that expert testimony satisfies Daubert almost always results in its admission at trial, a defendant may object on the additional grounds that the admission of the expert testimony would violate Fla. Stat. 90.403. This is most likely to succeed if the expert testimony offers little actual value but would unnecessarily inflame, confuse, or mislead the jury.

If someone is arrested and formally charged in Florida in a case involving potential admission of expert testimony, it is critical to find experienced and trusted legal representation as soon as possible. This decision could make the difference in whether or not someone faces a lengthy prison term and hefty fines.

Criminal Defense Attorney in Tallahassee, FL

Don Pumphrey, Jr. is a Former Prosecutor, Former State Police Officer, Lifetime Member of the Florida Association of Criminal Defense Lawyers; for over 25 years as a private defense attorney who is Trusted, Experienced, Aggressive in Criminal Defense as a Trial Attorney, Criminal Lawyer, Criminal Defense Lawyer for the accused in Florida State Courts located in Tallahassee, Florida but handling cases throughout the State of Florida.

Don Pumphrey, Jr. and the Tallahassee criminal defense lawyers at Pumphrey Law have decades of experience fighting drug charges on behalf of clients and winning. Call Pumphrey Law now at (850) 681-7777 to learn more about what we can do for you. Our lawyers will be happy to provide you with a free consultation.

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