By Will Dasher
Many people first see a breathalyzer in action while watching the hit TV shows “Cops” or “Live PD.” Typically, you watch a man or woman suspected of driving under the influence blow into a small device held by a police officer for a few seconds before a number appears, indicating that person’s level of blood alcohol content (BAC). This article takes a deeper dive into the science behind breathalyzers and how they work.
Breathalyzers are devices widely used by law enforcement to estimate blood alcohol content (BAC) from a breath sample. This tool has become integral in enforcing drunk driving laws and maintaining road safety. Breathalyzers rely on chemical reactions that occur when alcohol in the breath interacts with the device’s sensors, which then produce an electrical signal proportional to the amount of alcohol present. Understanding how breathalyzers work is crucial for both law enforcement and drivers, as it directly impacts legal proceedings and personal safety.
Chemical Principles Behind Breathalyzers
The most common type of breathalyzer uses a chemical reaction involving a chromic acid compound that oxidizes ethanol in the breath, changing color in the process. This color change is quantitatively analyzed to estimate BAC. The principle is based on the fact that the chemical reaction directly correlates with the alcohol concentration, allowing for a relatively accurate reading. This method, while effective, requires careful calibration and maintenance to ensure accuracy.
Infrared Spectroscopy Breathalyzers
Another sophisticated approach involves infrared spectroscopy, which identifies molecules based on the absorption of infrared light. Each chemical compound, including ethanol, absorbs light differently, creating a unique spectral fingerprint. In this type of breathalyzer, when the breath passes through the device, an infrared light beam is absorbed by ethanol molecules, and the level of absorption indicates the concentration of alcohol. This technology is generally more accurate and less susceptible to false readings from other substances.
Fuel Cell Technology in Breathalyzers
Fuel cell breathalyzers represent a more recent technological advancement. These devices use an electrochemical process where alcohol in the breath is oxidized at an electrode, generating an electric current. The strength of this current is proportional to the alcohol concentration, offering quick and reliable measurements. Fuel cell breathalyzers are known for their accuracy and reliability, making them a preferred choice for law enforcement.
Legal and Calibration Standards
Breathalyzers must adhere to strict calibration standards to maintain accuracy. In the United States, the National Highway Traffic Safety Administration (NHTSA) sets these standards, requiring regular calibration checks. Calibration involves adjusting the breathalyzer to ensure that it provides correct readings, using controlled samples of known alcohol concentration. This process is critical because even a slight miscalibration can lead to wrongful DUI convictions or dismissals.
Breathalyzer Accuracy and Limitations
While breathalyzers are a vital tool in DUI enforcement, they are not infallible. Factors such as the individual’s breathing pattern, recent alcohol consumption, or the presence of certain chemicals can affect the accuracy of the readings. For example, mouth alcohol—alcohol still present in the mouth rather than in the lungs—can significantly skew results. Thus, law enforcement officers are trained to observe a 15-20 minute observation period to minimize such issues.
Breathalyzer Use in Law Enforcement
In law enforcement, officers use breathalyzers during traffic stops when alcohol impairment is suspected. The procedure typically involves observing the suspect for signs of impairment, administering field sobriety tests, and finally, requesting a breath sample. The results can be used as evidence in DUI cases, though they are often supplemented by blood tests for greater accuracy.
Public and Legal Repercussions
The readings from a breathalyzer test can have significant legal consequences. A BAC reading over the legal limit (commonly 0.08% in many jurisdictions) can lead to charges of DUI or DWI. These charges can result in penalties such as fines, license suspension, or even jail time. Consequently, the accuracy of breathalyzers is a critical issue, with implications for both public safety and individual rights.
Technological Advances and Future Trends
Technological advances continue to refine breathalyzer accuracy and reliability. Developments in sensor technology and digital reporting are making these devices not only more precise but also easier for law enforcement to use in the field. Future trends may include more integration of digital technology, allowing real-time data analysis and even remote monitoring of alcohol levels.
The Accuracy Debate
As a former prosecutor who dealt with these devices regularly, I can share some insights. Are these handheld devices reliable? I’d lean towards no. Here’s why: First, these devices are seldom calibrated. Second, they can mistakenly detect other substances in your breath as alcohol. For instance, diabetics with acetone in their system might show a false positive for alcohol.
Before You Blow, Think Twice
Caught in a roadside stop? Consider this before agreeing to blow into a handheld breathalyzer: This test is optional. Unlike the fixed units at police stations, which can be used against you and lead to a suspended license if you refuse, these portable versions offer you a choice. Always speak with an attorney before surrendering your rights.
CALL THE Blitch Law Firm ATTORNEYS AT LAW TODAY TO DISCUSS YOUR CASE
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Categories: Criminal Defense, DUI Defense