A recent Florida DUI manslaughter case involving allegations of alcohol impairment and measurable Delta-9 THC in the driver’s blood has raised major questions about scientific evidence, toxicology testimony, and the admissibility of marijuana-related evidence in criminal court. The trial court denied a defense challenge seeking to exclude testimony from a toxicologist concerning the effects of Delta-9 THC and its alleged interaction with alcohol.

The court’s ruling focused on whether the scientific testimony met Florida’s Daubert reliability standard and whether the jury should hear evidence concerning THC impairment. Importantly, the court emphasized that the State still bears the burden of proving impairment beyond a reasonable doubt.

At the same time, the ruling illustrates an important issue facing many DUI defendants in Florida: prosecutors increasingly rely on toxicology experts to explain alleged impairment involving substances other than alcohol. These cases can become highly technical and often require extensive litigation over scientific evidence, laboratory methodology, toxicology interpretation, and causation.

If you or someone you care about is under investigation for DUI manslaughter, DUI involving controlled substances, or a serious felony DUI charge in Florida, speaking with an experienced DUI defense attorney immediately may be critical.

Learn more about the defense approach used by the Law Office of W.F. “Casey” Ebsary Jr. at DUI2Go.com or review attorney credentials and background at About W.F. Casey Ebsary Jr..

Understanding the Court’s Ruling

The court addressed whether the prosecution could introduce evidence that the defendant allegedly had measurable Delta-9 THC in her blood at the time of the crash.

According to the order, the court concluded:

The ruling specifically discussed:

• Delta-9 THC as the active impairing substance in marijuana
• The alleged additive effect between alcohol and THC
• The absence of a universally accepted THC impairment threshold
• Whether toxicology testimony would assist the jury

The court also emphasized that no “per se” THC impairment number currently exists in Florida law similar to the .08 alcohol standard.

That distinction is important because alcohol DUI cases and marijuana-related DUI cases are often litigated differently.

Why THC DUI Cases Are So Complex

Unlike alcohol cases, marijuana impairment cases frequently involve competing interpretations of toxicology evidence.

In alcohol-only DUI prosecutions, prosecutors often rely heavily on breath or blood alcohol concentration results. However, THC-related DUI cases can involve significantly more debate concerning:

• Absorption rates
• Frequency of marijuana use
• Tolerance
• Timing of consumption
• Residual THC presence
• Individual physiology
• Laboratory testing methods

The court order itself acknowledged that impairment allegedly depends on multiple variables.

That means these cases often become battles between experts.

Key Differences Between Alcohol and THC DUI Allegations

The Importance of Daubert Challenges in Florida DUI Cases

Florida courts use the Daubert standard to evaluate whether expert testimony is scientifically reliable and relevant before it is presented to a jury.

A Daubert challenge can involve arguments concerning:

• Scientific reliability
• Peer-reviewed research
• Error rates
• Methodology
• Expert qualifications
• Relevance to the issues in the case

In serious felony DUI prosecutions, these hearings may become one of the most important parts of the defense strategy.

The ruling discussed here demonstrates that prosecutors may attempt to use toxicologists to explain:

• Alleged impairment
• Reaction time
• Divided attention issues
• Driving performance
• Combined alcohol and THC effects

A defense attorney may challenge whether the proposed testimony satisfies Florida evidentiary standards.

For information about aggressive DUI defense representation in Florida, visit Florida DUI Defense Lawyer.

DUI Manslaughter Charges in Florida

DUI manslaughter allegations are among the most serious criminal charges prosecuted in Florida courts.

These cases may involve:

• Fatal traffic crashes
• Blood testing
• Accident reconstruction
• Toxicology experts
• Law enforcement crash investigators
• Cell phone evidence
• Vehicle data downloads
• Medical testimony

A conviction can expose a defendant to severe penalties, including substantial prison exposure.

However, every accused person remains presumed innocent unless the State proves guilt beyond a reasonable doubt.

Common Areas of Defense Investigation in Serious DUI Cases

THC and Alcohol: The “Additive Effect” Issue

One major issue in the ruling involved testimony concerning the alleged “additive effect” between alcohol and Delta-9 THC.

The toxicologist reportedly testified that both substances are central nervous system depressants and may allegedly increase impairment when combined.

The court concluded that this testimony was sufficiently reliable to be heard by a jury.

However, defense attorneys may still challenge:

• The scope of the expert’s conclusions
• Whether the science applies to a specific defendant
• Whether the expert is overstating impairment
• Whether the State can prove actual impairment at the relevant time

These cases often require careful cross-examination and independent expert review.

Why Blood Test Evidence Is Not Always Simple

Many people assume blood testing automatically proves impairment. That is not necessarily true.

Blood evidence can raise numerous questions, including:

• Was the sample properly preserved?
• Was testing properly conducted?
• Was the chain of custody maintained?
• What do the numbers actually mean?
• Can toxicology establish impairment?
• Was the substance active or inactive?
• Could the result reflect prior use rather than current impairment?

The court order discussed measurable Delta-9 THC levels, but also acknowledged there is no universally accepted THC impairment threshold comparable to alcohol standards.

That distinction can become central in litigation.

DUI Manslaughter Litigation Often Requires Multiple Experts

Serious DUI felony cases may involve testimony from:

Complex felony DUI cases may require a defense team capable of challenging highly technical scientific evidence.

Attorney W.F. “Casey” Ebsary Jr. is a Board Certified Criminal Trial Lawyer with extensive DUI defense experience. Learn more at Meet Casey Ebsary Jr..

What Makes Florida DUI Cases Different?

Florida DUI prosecutions can involve aggressive investigation techniques and sophisticated forensic evidence.

In some cases, prosecutors may attempt to use:

• Breath test results
• Blood test evidence
• Field sobriety exercises
• Body camera footage
• Surveillance video
• Crash reconstruction analysis
• Toxicology testimony

The legal and scientific issues may overlap extensively.

That is especially true in cases involving allegations of controlled substances.

Timeline of a Typical Serious DUI Case

10 Frequently Asked Questions About DUI Manslaughter and THC Evidence

The Role of Jury Interpretation

One important aspect of the ruling is the court’s conclusion that the degree of impairment ultimately becomes a jury question.

That means jurors may hear competing testimony from prosecution and defense experts concerning:

• THC levels
• Alcohol interaction
• Reaction time
• Driver behavior
• Toxicology limitations
• Scientific uncertainty

The defense may argue the State failed to establish impairment beyond a reasonable doubt.

Why Early Investigation Matters

In serious DUI cases, evidence can disappear quickly.

Potential evidence may include:

• Surveillance footage
• Vehicle electronic data
• Witness recollections
• Crash scene measurements
• Phone records
• Toxicology documentation

Early investigation can be critical.

If you need legal representation for a DUI or DUI manslaughter investigation in Florida, contact the Law Office of W.F. Casey Ebsary Jr. through DUI2Go Contact Page.

Scientific Evidence Continues to Evolve

One important takeaway from this ruling is that courts continue to confront emerging scientific and legal questions involving marijuana-related DUI allegations.

As marijuana laws and usage patterns evolve nationally, litigation involving:

• Toxicology interpretation
• THC impairment
• Driving behavior
• Expert testimony
• Scientific reliability

will likely continue to expand in Florida courtrooms.

That does not mean every prosecution automatically succeeds.

Each case remains fact-specific.

Choosing the Right DUI Defense Attorney Matters

Not every criminal defense case involves complex scientific litigation.

DUI manslaughter cases involving blood evidence, toxicology experts, and Daubert hearings may require extensive preparation and technical understanding.

When evaluating legal representation, factors may include:

Attorney W.F. “Casey” Ebsary Jr. is Board Certified in Criminal Trial Law and represents individuals facing serious DUI allegations throughout Florida.

Learn more at:

• DUI2Go Homepage
• Attorney Bio Page
• Contact the Law Office

Final Thoughts

This Florida DUI manslaughter ruling demonstrates how modern DUI prosecutions increasingly involve scientific testimony concerning substances beyond alcohol alone. The court allowed the prosecution to introduce expert testimony concerning Delta-9 THC and its alleged interaction with alcohol after determining the testimony satisfied Florida’s Daubert reliability requirements.

At the same time, the ruling also acknowledged important limitations in the science, including the absence of a universally accepted THC impairment threshold comparable to alcohol standards.

For defendants facing serious DUI allegations, these cases may involve highly technical disputes over toxicology, impairment, laboratory methodology, and causation. The prosecution still carries the burden of proving guilt beyond a reasonable doubt.

If you or a loved one is facing a DUI investigation or felony DUI charge in Florida, speaking with an experienced DUI defense attorney immediately may help protect your rights, preserve evidence, and prepare a strategic defense.

Drug Recognition Experts (DRE) in Florida and throughout the nation have raised concerns among defense attorneys, jurors and judges. This is because law enforcement and prosecutors aim to influence the independent judgment of these legal authorities in determining the potential impairment of criminal suspects.

We’ve acquired training manuals and carefully scrutinized the evidence supporting these so-called “experts.” Upon examination, it becomes apparent that these witnesses may not meet the rigorous requirements for the admissibility of “scientific” evidence, especially outside of law enforcement circles. Consequently, it is prudent to consider removing such witnesses from the list of prosecution witnesses.

Florida Drug Recognition Experts DRE

In just five minutes, you can gain insights into various aspects of DRE:

The History and Origin of the DRE.
The Comprehensive Training Regimen for Drug Recognition Experts (DRE).
The Entities Responsible for Conducting DRE Training.
The Unique Skillset Acquired by Drug Recognition Experts (DRE) that may not be readily available to judges and jurors.
Whether DRE “evidence” aligns with the standards for admissibility set forth by Florida law and the Daubert standard.”

Using Drug Recognition Experts (DRE), in Florida DUI cases and across the nation, law enforcement and prosecutors are trying to circumvent the ability of jurors and Judges to reach their own conclusions as to the impairment, if any, of criminal suspects.

We have obtained training manuals and reviewed the evidence used to support these “experts” and you may also conclude the ability of these witnesses to meet the stringent requirements for admissibility of “scientific” evidence is far from generally accepted within any communities other than law enforcement. Such witnesses should be stricken from Prosecutors’ witness lists.

In five minutes you will know: What is the History and Origin of the DRE? What is done during Drug Recognition Experts (DRE) training? Who does the DRE training? What special skills are Drug Recognition Experts (DRE) taught that judges and jurors don’t already have? Does DRE “evidence” meet the standard for admissibility under Florida law and the Daubert standard?

What is the History and Origin of the Drug Recognition Expert (DRE}?

The Los Angeles Police Department developed this area of alleged expertise in the 1970’s. The federal law enforcement agency, the National Highway Traffic Safety Administration (NHTSA) soon jumped on the bandwagon. Strikingly, the “certification” is now issued by the cop’s own International Association of Chiefs of Police (IACP) and not by a generally recognized educational or scientific institution.

What is done during DRE training?

A Seven (7) day school is supposed to cover a 706-page manual. The curriculum begins by citing the Frye standard for admissibility, a standard that was abandoned in Florida in 2013 (see discussion below: Does DRE “evidence” meet the standard for admissibility under Florida law and the Daubert standard ? ).

During the 7 day romp, cops are allegedly trained in the following areas to use at the roadside: Eye examinations; Physiology; Vital signs; the Central Nervous System; Depressants; Stimulants; Physician’s Desk Reference; Dissociative Anesthetics; Narcotic Analgesics. That is only half of the allegedly scientific in-depth training.

Let’s visit the second half of this highly accelerated educational program:  Inhalants, Vital Signs, Cannabis; Signs and Symptoms; Drug combinations; Writing a resume (Curriculum Vitae); and wrap it up with a list of questions defense attorneys will ask when the newly minted expert tries to spew this garbage in court.

Seven days to a better you – In short, street cops become quasi-medical professionals in only one week.

Who does the Drug Recognition Experts (DRE) training?

The National Highway Traffic Safety Administration (NHTSA) and the International Association of Chiefs of Police (IACP).

What special skills are Drug Recognition Experts (DRE) taught that judges and jurors don’t already have?

None. Generally, witnesses are not allowed to opine on the guilt or innocence of the accused. When police try to use these “experts” they are attempting to tell the jury how to rule and why. Since the alleged expert issues a highly prejudicial opinion on an ultimate issue in the case, courts must allow only legally admissible evidence to reach jurors.

Does Drug Recognition Experts (DRE) “evidence” meet the standard for admissibility under Florida law and the Daubert standard? 

No. In July 2013,  Section 90.704, Florida Statutes, was amended to read: “Facts or data that are otherwise inadmissible may not be disclosed to the jury by the proponent of the opinion or inference unless the court determines that their probative value in assisting the jury to evaluate the expert’s opinion substantially outweighs their prejudicial effect.” Since, 2013, there is little guidance from courts and judges on the validity of this testimony.

Florida Rule of Criminal Procedure 3.220 requires disclosure of “reports or statements of experts made in connection with the particular case, including results of physical or mental examinations and of scientific tests, experiments, or comparisons . . . .” The rules also discuss, “expert witnesses who have not provided a written report and a curriculum vitae or who are going to testify . . . .”  In 1996, the rules also contemplated, “experts who have filed a report and curriculum vitae and who will not offer opinions subject to the Frye test.” FRCP 3.220 at 151 Note ( July 1, 2014).

Florida Drug Recognition Experts DRE are only alleged experts who issue highly prejudicial opinions on ultimate issues in the case, courts must allow only legally admissible evidence to reach jurors under the 2013 amendments to Florida law and the ruling of the United States Supreme Court in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), General Electric Co. v. Joiner, 522 U.S. 136 (1997), and Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999), and to no longer apply the standard in Frye v. United States, 293 F.2d 1013 (D.C. Cir 1923) . See generally, http://laws.flrules.org/2013/107 .

Standardized 12-Step Drug Recognition Experts Protocol

The 12-Step Drug Recognition Experts (DRE) Protocol is standardized because it is conducted the same way, by every drug recognition expert, for every suspect whenever possible. In the above video, the 12-Step Drug Recognition Experts (DRE) Protocol is not shown.

1. Breath Alcohol Concentration (BAC) Test administered to suspect
2. Interview with the Arresting Officer about BAC, the reason for stop & suspect’s behavior, appearance, and driving.
3. Preliminary Examination and First Pulse. DRE asks questions about health, recent food, alcohol, and drugs, including prescribed medications while DRE observes suspect’s attitude, coordination, speech, breath, and face. DRE examines pupils uses horizontal gaze nystagmus (HGN) and takes suspect’s pulse. If needed seek medical assistance immediately. Otherwise, the evaluation continues.
4. Eye Examination. behavior, appearance, and driving. DRE uses HGN, vertical gaze Nystagmus (VGN), and looks for a lack of convergence.
5. Divided Attention Psychophysical Tests. DRE administers the Modified Romberg Balance, the Walk and Turn, the One Leg Stand, and the Finger to Nose test.
6. Vital Signs and Second Pulse. DRE takes the subject’s blood pressure, temperature, and pulse.
7. Dark Room Examinations. DRE measures at pupil sizes under three different lighting conditions.
8. Examination of Muscle Tone. DRE examines the subject’s skeletal muscle tone (normal rigid, or flaccid).
9. Check for Injection Sites and Third Pulse. DRE looks for injection sites and takes suspect’s pulse.
10. Subject’s Statements and Other Observations. DRE reads Miranda, asks questions about drug use.
11. Analysis and Opinions of the Evaluator. DRE forms an opinion as the suspect is impaired. If DRE believes there is impairment, then the category of drugs will be indicated.
12. Toxicological Examination. DRE requests a urine, blood and/or saliva for toxicology lab analysis.

Sources: http://www.wsp.wa.gov/breathtest/dredocs.php