If you’ve been stopped by a police officer on suspicion of driving while intoxicated (DWI), you may be asked to blow into a small handheld device at the side of the road. This device is known as a Portable Breath Test (PBT).
Many drivers mistakenly believe that this roadside breath test is the same as the breath test administered later at the police station. It is not.
Understanding the difference between a Portable Breath Test and a chemical breath test is important because they serve different purposes under New York law.
What Is a Portable Breath Test (PBT)?
A Portable Breath Test is a handheld device used by law enforcement officers during a roadside DWI investigation.
The officer typically asks a driver to blow into the device shortly after a traffic stop. The PBT provides an estimate of the alcohol concentration in a person’s breath within seconds.
Unlike the larger evidentiary breath-testing instruments used at police headquarters, a PBT is designed primarily as an investigative tool during the initial stages of a DWI investigation.
Why Do Police Officers Use a Portable Breath Test?
Officers use a PBT to assist them in deciding whether there is probable cause to make a DWI arrest.
The PBT is only one factor that an officer may consider. During a typical investigation, an officer may also evaluate:
- Driving behavior
- The odor of an alcoholic beverage
- Bloodshot or watery eyes
- Slurred speech
- Admissions regarding alcohol consumption
- Performance on standardized field sobriety tests
- The results of the Portable Breath Test
No single observation automatically establishes intoxication. Instead, officers evaluate the totality of the circumstances when deciding whether probable cause exists.
Is a Portable Breath Test the Same as the Breath Test at the Police Station?
No.
This is one of the most common misconceptions in DWI cases.
A Portable Breath Test is administered at the roadside using a handheld device.
A chemical breath test is generally administered after an arrest at the police station using an evidentiary breath-testing instrument that is subject to more rigorous testing, calibration, maintenance, and regulatory requirements.
The roadside PBT and the post-arrest chemical test serve different legal purposes.
Are Portable Breath Test Results Admissible in Court?
In New York, Portable Breath Tests generally are not used to prove a driver’s blood alcohol concentration (BAC) at trial. Instead, they are typically offered, if at all, on the issue of whether the officer had probable cause to arrest the driver.
That distinction is important. A PBT is an investigative tool—not a substitute for the evidentiary chemical test administered after arrest.
Whether a PBT result may be admitted, and for what purpose, depends on the circumstances of the case and the applicable rules of evidence.
Can a Portable Breath Test Be Wrong?
Like any scientific instrument, the accuracy of a Portable Breath Test depends on numerous factors, including:
- Proper calibration
- Regular maintenance
- Correct administration
- Environmental conditions
- Operator training
- The specific device being used
Defense attorneys often examine maintenance records, calibration records, officer training, and the manner in which the test was administered when evaluating a DWI case.
What Happens If You Refuse a Portable Breath Test?
Whether a driver may refuse a Portable Breath Test, and the legal consequences of doing so, depends on the circumstances and the applicable provisions of New York law.
Drivers should understand that the rules governing a roadside Portable Breath Test are different from those governing the post-arrest chemical breath test under New York’s implied consent law. Also, the process for administering both are different.
Because the legal consequences differ, it is important not to confuse the two.
Can a DWI Attorney Challenge a Portable Breath Test?
Yes.
Depending on the facts of the case, an attorney may examine issues such as:
- Whether the device was properly maintained
- Whether it was properly calibrated
- Whether the officer followed applicable procedures
- Whether the officer had sufficient probable cause before requesting additional testing
- Whether the PBT result was relied upon appropriately during the investigation
Every case is different, and the significance of a Portable Breath Test depends on the totality of the evidence.
Charged with DWI in New York?
A Portable Breath Test is only one part of a DWI investigation. The strength of the prosecution’s case depends on many factors, including the legality of the traffic stop, the officer’s observations, field sobriety testing, chemical testing, and compliance with New York law.
At The Law Office of Siara Ossa PLLC, we thoroughly review every aspect of a DWI investigation to determine whether the evidence was lawfully obtained and whether legal or factual defenses may be available.
If you have been charged with DWI in New York, contact our office to discuss your case and your legal options.
The Law Office of Siara Ossa PLLC
780 Long Beach Boulevard
Long Beach, New York 11561
(t):347-733-5612
siara@ossalawny.com