Breath Testing

In New Britain, police officers who suspect that a driver is operating their vehicle under the influence of drugs or alcohol may request that the driver take a breath test. On this page, you can learn more about implied consent laws in the state, breath test machines and how they work, and potential defenses to a failed breath test.


New Britain police officers use breath testing machines, often called breathalyzers to test the blood alcohol concentration in drivers that are arrested for a DUI. The purpose of the breathalyzer is to provide the police with scientific evidence to use against the arrestee in a DUI case. You can learn more about New Britain breathalyzers on this page.

Breath Testing Machines

The way that these machines are used is by the subject inhaling and then exhaling through a small mouthpiece on the breathalyzer device. This air travels through the device and passes over beams of infrared light.

The science behind the breathalyzer is somewhat complicated but in the simplest terms, it is based on a law called Henry’s Law. Henry’s Law is defined as, “mass of gas that dissolves in a definite volume of liquid which is directly proportional to the pressure of the gas provided that the gas doesn’t react with the solvent.” This means that if a gas and a liquid are confined in a closed space, the concentration of gas to air above the liquid is the same as the gas dissolved in the liquid.

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An example of this is an amount of blood containing alcohol in a closed container, where the alcohol evaporates until the concentration in the air above the blood is equal to the concentration in the blood. What is known as Henry’s constant is the ratio of the blood in the human body to the air, which is measured 2100:1. This means that the average concentration of alcohol in the blood is around 2100 times more than the concentration in the air.

Issues With Breath Testing

The problem with this, however, is that every single person is different in size, weight, and physical makeup. This complicates the term “normal” when it comes to blood to air equilibrium. Scientists have estimated that there is likely a 0.03% error or higher in each breathalyzer due to the complications with the normal ratio being used as a constant in the device.

Another factor that can complicate the reliability of the breathalyzer results is the body temperature of the test subject. Body temperature varies from person to person, and even a slight increase or decrease in body temperature can alter the blood alcohol concentration. Other factors like taking a large dose of aspirin, having diabetes, or being sick can call the reliability of the breath test into question.

Not only can the person taking the breathalyzer affect the results, but problems with the device itself can render the results unreliable. The most common issue is poor maintenance and improper calibration of the device. Calibration must be proper and maintained at consistent, set intervals, and the person administering the test must be trained and certified in the administering of the test to ensure that it is done correctly. The administer of the test must make sure that the test subject does not take the test immediately after burping, vomiting, eating, or smoking. Lastly, the breath test is reliable only if it captures two reliable results in measurements that are within .02 of each other.

Your DUI Charge

Although Connecticut has an implied consent law, meaning every person that gets behind the wheel implicitly consents to a breathalyzer, drivers still have the freedom to decline a breathalyzer. Though declining a breathalyzer can lead to consequences such as automatic license suspension, taking the breathalyzer could lead to far more serious consequences in the criminal case for a DUI. This is a personal decision that a person faces when asked to submit to a breath test. A good DUI attorney will understand how to analyze a DUI case and recognize possible defenses and issues with the breath test. If you are facing a DUI charge in New Britain, call Lady DUI today to find out how we can help you.

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