Breath Test Defense In Florida DUI Cases
Daytona Beach DUI Defense Lawyer
Retired Homicide Detective. Former DUI Investigator. Trial Attorney.
Many people believe a breath test result ends a DUI case.
It does not.
One of the most common statements heard after a DUI arrest is:
“I blew over the legal limit. There’s nothing I can do.”
That belief is often wrong.
Breath testing devices are sophisticated instruments, but they are not perfect.
They are operated by human beings.
They require maintenance.
They require calibration.
They require compliance with strict rules and procedures.
When mistakes occur, breath test results may become unreliable.
At the Law Offices of Patrick J. McGeehan, P.A., we carefully evaluate every aspect of breath test evidence.
Before becoming a lawyer, Patrick served as a police officer, DUI investigator, police instructor, traffic homicide investigator, and homicide detective.
He understands how DUI investigations are conducted because he participated in them.
Today, he uses that experience to challenge breath test evidence and protect his clients’ rights.
What Is A Breath Test?
A breath test is designed to estimate the amount of alcohol in a person’s breath and convert that measurement into an estimated blood alcohol concentration.
In Florida, a breath alcohol level of .08 or greater may support a DUI charge.
However, the machine does not directly measure alcohol in the blood.
Instead, it estimates blood alcohol concentration based upon breath samples.
That distinction is important.
Because the result is an estimate, numerous factors can affect accuracy.
Breath Tests Are Not Infallible
Many jurors assume breath test machines are perfectly accurate.
They are not.
Like any scientific instrument, breath testing devices are subject to limitations.
Potential issues include:
- Mechanical failures
- Calibration problems
- Maintenance deficiencies
- Human error
- Environmental influences
- Physiological differences
The existence of a breath test result does not automatically prove guilt.
The Legal Limit Is Not Always The End Of The Case
Many drivers are charged with DUI because they allegedly produced a breath result above .08.
However, the issue is often more complicated than simply looking at a number.
Questions may include:
- Was the machine functioning properly?
- Was the operator properly trained?
- Were procedures followed?
- Was the observation period completed?
- Was the result affected by outside influences?
Every breath test result should be carefully examined.
How Breath Testing Machines Work
Breath testing instruments analyze a person’s breath sample and attempt to estimate alcohol concentration.
The machine assumes a relationship between alcohol in the breath and alcohol in the bloodstream.
This process involves scientific assumptions and calculations.
As with any scientific process, errors can occur.
Common Breath Test Problems
Calibration Issues
Breath testing instruments require regular calibration.
If a machine is not properly calibrated, the accuracy of the results may be questioned.
Maintenance Problems
Like any mechanical device, breath testing equipment requires maintenance.
Equipment failures may affect reliability.
Operator Error
Breath testing procedures must be properly followed.
Mistakes by operators can create issues regarding the validity of results.
Observation Period Violations
Florida breath testing procedures generally require observation before testing.
Failure to properly observe a subject may affect the reliability of the result.
Radio Frequency Interference
Electronic interference has been the subject of litigation in DUI cases for years.
Depending on the circumstances, interference issues may become relevant.
Software Issues
Modern breath testing instruments rely upon computer systems and software.
Questions sometimes arise regarding:
- Software accuracy
- Programming issues
- Data integrity
Medical Conditions That Can Affect Breath Tests
Certain medical conditions may influence breath test results.
Examples may include:
Gastroesophageal Reflux Disease (GERD)
GERD can sometimes cause alcohol from the stomach to enter the mouth and affect testing.
Acid Reflux
Acid reflux issues may create concerns regarding breath sample accuracy.
Diabetes
Certain medical conditions may affect chemical compounds present in breath.
Dental Work
Dental appliances may occasionally become relevant during breath test evaluations.
Respiratory Conditions
Breathing disorders sometimes affect a person’s ability to provide a proper breath sample.
Each case requires careful evaluation of the facts.
The Observation Period
One of the most important aspects of breath testing involves the observation period.
Officers are generally expected to observe the individual before testing.
The purpose is to help ensure the person does not:
- Vomit
- Regurgitate
- Eat
- Drink
- Place objects in the mouth
Violations of the observation period may create questions regarding the validity of the result.
Mouth Alcohol Issues
Breath testing assumes the alcohol being measured comes from deep lung air.
Alcohol present in the mouth can potentially affect results.
Sources may include:
- Vomiting
- Burping
- Regurgitation
- Certain substances introduced into the mouth
Proper procedures are designed to minimize these concerns.
Breath Test Refusals
Not every DUI case involves a breath test result.
Some drivers refuse testing.
Refusal cases create different legal issues involving:
- Driver’s license suspensions
- Implied consent laws
- Evidentiary issues
Related Page:
DUI Refusal Cases
Breath Tests And Field Sobriety Exercises
Breath tests are often only one part of a DUI investigation.
Officers may also rely upon:
- Driving behavior
- Observations
- Field sobriety exercises
- Statements
If field sobriety exercises were improperly administered, that may affect the overall strength of the case.
Related Page:
Field Sobriety Exercises
Can A Breath Test Result Be Wrong?
Yes.
Although breath testing technology has improved over the years, errors still occur.
Potential sources of error include:
- Equipment issues
- Human error
- Medical conditions
- Procedural violations
- Environmental factors
The existence of a breath test result does not end the investigation.
Breath Test Evidence And Trial
At trial, breath test evidence is typically presented through witnesses and documentary records.
Potential issues may include:
- Machine maintenance records
- Calibration records
- Operator qualifications
- Testing procedures
- Scientific reliability
A thorough review of these issues is often essential.
Common Defenses To Breath Test Evidence
Every case is different.
Potential defenses may include:
Illegal Traffic Stop
If the stop was unlawful, evidence may be subject to suppression.
Lack Of Probable Cause
The officer must have legal grounds for arrest.
Observation Period Violations
Improper observation procedures may affect reliability.
Maintenance Problems
Equipment maintenance issues may undermine confidence in the results.
Operator Error
Failure to follow proper procedures may create significant issues.
Medical Conditions
Medical explanations may exist for certain results.
Constitutional Issues
Certain cases involve constitutional challenges requiring careful analysis.
Frequently Asked Questions
If I Blew Over .08, Am I Guilty?
No.
The State must still prove its case beyond a reasonable doubt.
Can Breath Tests Be Wrong?
Yes.
Various factors may affect the accuracy and reliability of results.
Are Breath Tests Always Admissible?
Not necessarily.
Questions regarding procedures, maintenance, and compliance may arise.
What If I Have GERD Or Acid Reflux?
Certain medical conditions may affect breath testing and should be carefully evaluated.
Can My DUI Case Be Dismissed Even If I Took A Breath Test?
Some DUI cases are dismissed or successfully challenged despite the existence of breath test results.
Every case depends upon its specific facts and evidence.
Why Clients Choose Patrick J. McGeehan
Many attorneys handle DUI cases.
Few have participated in DUI investigations before becoming lawyers.
Patrick’s background includes:
- Former DUI Investigator
- Police Officer
- Police Instructor
- Retired Traffic Homicide Investigator
- Retired Homicide Detective
- Trial Attorney
Most attorneys learn about breath testing from reports and training materials.
Patrick participated in the investigative process himself.
That experience provides valuable insight when evaluating breath test evidence.
A Career Dedicated To Examining Evidence
Every DUI case raises important questions.
Was the machine functioning properly?
Were procedures followed?
Was the observation period completed?
Could outside factors have affected the result?
Patrick has spent decades evaluating evidence and investigating those questions.
As a police officer, DUI investigator, traffic homicide investigator, homicide detective, and trial attorney, he has devoted his career to uncovering facts and determining the truth.
That same commitment guides every DUI defense case today.
Contact A Daytona Beach DUI Defense Lawyer
A breath test result does not automatically determine the outcome of a DUI case.
The machine matters.
The procedures matter.
The evidence matters.
Do not assume the State’s evidence is correct without careful review.
Contact the Law Offices of Patrick J. McGeehan, P.A. today to schedule a consultation and learn how an experienced Daytona Beach DUI defense lawyer can help protect your rights and your future.
Resources:
Leaving the Scene of an Accident With a Death
Fatal Crash Investigations in Florida