How Do Breathalyzers Work?

How Do Breathalyzers Work?


If you’ve ever been pulled over for suspicion of DUI in Virginia, there’s a good chance that you were asked to submit to a breathalyzer test. These devices may seem as if they magically measure the amount of alcohol content in your body, but there is some science inside those boxes. The result that a breathalyzer produces could influence an officer’s decision on your arrest, or it may validate an arrest that already took place.

How Alcohol is Detected on Your Breath

When a person has been drinking, you can usually smell alcohol on their breath. This is something that’s highly subjective as the smell could be the same whether you have had one drink or many. A breathalyzer doesn’t “sniff” your breath but rather analyzes the presence of alcohol in your system at the molecular level.

Alcohol molecules are so tiny that they will pass through your stomach’s wall into your blood stream. This happens within minutes after you begin drinking that wine, beer, or other cocktail. After it enters your bloodstream, the alcohol will also travel through your lungs, and some of it will evaporate into your outgoing breath.

How Does a Breathalyzer Work?

When you breathe into a breathalyzer, the device can measure the amount of alcohol in your breath, which translates to your blood alcohol content (BAC). In Virginia, the legal limit is 0.08, but the laws will vary for underage drinkers or those who have a commercial driver’s license. This mathematical estimation of your BAC can be provided by several different varieties of breathalyzer technology.

  • Semiconductor Sensor Breathalyzers. If you have a personal breathalyzer, it is probably one of this variety. These relatively affordable devices will oxidize alcohol molecules using a low-voltage semiconductor that is created from metal oxide. When you breathe into the device, the breathalyzer will oxidize the molecules, and the affected electrical current will produce your BAC. Unfortunately, these machines are also prone to providing false positive results.
  • Fuel-Cell Breathalyzers. A police officer giving a breath test on the side of the road will most likely use one of these devices, which works in a similar fashion to a semiconductor breathalyzer. The difference is that these machines are specifically calibrated for alcohol, so they are more precise.
  • Infrared Spectroscopy Breathalyzers. This is a bulkier and more expensive unit that you will most likely find sitting in a police station. When you breathe into one of these breathalyzer machines, it measures your BAC by sending your breath through infrared light. Alcohol molecules absorb light differently, so they can be identified and then measured.

Are Breathalyzers Accurate?

Some breathalyzers are more accurate than others, but none of them are infallible. This is just one of the reasons why you should speak with a qualified Virginia DUI attorney if you are ever charged with a DUI.

There is a margin of error with most breathalyzers, and there are certain factors that can cast doubt on a positive result. These sensitive machines are supposed to be calibrated at least annually, so failure to do this could result in a test being disqualified. Some breathalyzers may give false results due to such things as acid reflux, blood in the mouth, and body temperature. Natural chemicals such as “ketones” have also been mistaken for alcohol in the bloodstream and returned positive results.            

Should You Agree to Take a Breathalyzer Test in Virginia?

One of the biggest misconceptions about breathalyzer tests is that you are compelled to take one if an officer puts it in front of you during a DUI stop. In Virginia, this is not the case. You do not have to agree to a preliminary breath test (PBT), which is part of the field sobriety test, and the results of one of these tests are not admissible in court.

Virginia is, however, an implied consent state, meaning that you have already given permission for a breath test if you are arrested for DUI. If the authorities charge you and take you to the police station, you must agree to take the test, or you will be subject to additional charges.

Getting arrested for DUI can be a terrifying experience. The truth is that everyone makes mistakes and there is a chance that the police made an error in handling your arrest. The consequences of a DUI conviction can be grave, so this is not something you should leave to chance.

The Pack Law Group can provide the strong defense you need and will take immediate steps to protect your rights. Contact our Bedford office now at (540) 586-7225.

Can I Refuse a Breathalyzer in Virginia?

Can I Refuse a Breathalyzer in Virginia?


Being pulled over for a DUI in Virginia can be a terrifying experience. Although a driver can refuse a breathalyzer test in this state, there can be dire consequences when making this choice. Virginia is an implied consent state, which gives the Commonwealth the right to punish you if you don’t agree to their request.

What is Implied Consent in Virginia?

Virginia’s implied consent law, found in VA Code §18.2-268.2(A), states that anyone who operates a motor vehicle in the state agrees to submit to a blood or breath test after they are arrested for DUI. These tests are meant to measure the driver’s blood alcohol content (BAC), which can show whether the driver was beyond the legal limit for their class. For example, the legal limit for an adult driver in Virginia is 0.08.

It wasn’t always that way. Originally, a blood or breath test was voluntary in Virginia. Then, a number of citizens decided they did not want to submit themselves to such scrutiny. That’s when the state took it upon itself to make it mandatory as part of the condition to operating a motor vehicle upon state highways. It is hidden in the small print when you apply for your driver’s license. Note – You have not actually consented to being tested. You have not signed any paperwork that specifically gives away your rights and allows you to be charged for DUI, the consent is “implied,” and a condition of using the roadways.

Reasonable suspicion can mean anything that the officer can justify. For example, the car was weaving, stopping and starting, or going too fast or slow. Any valid reason an officer may have to pull you over for DUI could be considered reasonable suspicion. Once that happens, the officer needs to have lawfully arrested the driver for DUI prior to administering the tests. The first request is supposed to be for a breathalyzer, or breath test that shows the level of alcohol in one’s system, usually using the Intoxilyzer 5000. The blood test should only be conducted if the breath test is not available.

What Are The Different Types of Breath Tests in Virginia?

Virginia has two types of breathalyzer tests, which can be confusing at best. The first is the Preliminary Breath Test (PBT), which is used on the roadside as part of the field sobriety test. This test is given as part of the officer’s process in determining whether to make an arrest for DUI. The results of a PBT cannot be used as evidence in court. No legal penalties exist if you refuse to take a PBT, although this decision could hasten a DUI arrest. The other test is a Breathalyzer Test that is administered at the police station after the arrest for DUI. By law, if you refuse to take a breathalyzer test after being arrested for DUI, you will be charged with another crime called “Breathalyzer Refusal in Virginia.” This is something that can be used against you in court.

What Happens If You Refuse A Breathalyzer In Virginia?

If you make the choice to refuse a post-arrest breathalyzer test, the police officer is required to read a form to you that details the nature of the implied consent law and outlines the penalties you will face for refusal. Provided you still refuse to take the test, you will receive an additional charge and may face those added penalties. These include:

  • Administrative Driver’s License Suspension. When you are charged with this offense, your driver’s license will be automatically suspended for a period of seven days. You cannot have a restricted license during this period, and this is in addition to any suspension that results from a conviction.
  • Driver’s License Suspension. Drivers who are convicted of refusing to take a breathalyzer test in Virginia will face an automatic license suspension of 12 months for the first offense. During this period, there is no opportunity to get a restricted license.
  • DMV Points. A first offense conviction will add six points to your DMV record.

If this was not the first time you’ve refused a post-arrest breathalyzer test in Virginia in the past ten years, the penalties would increase substantially. For example, a second or third conviction for this offense will have penalties that include the suspensions and points described above with the addition of jail time and fines up to $2,500.

Put Your Case in the Hands of an Experienced Virginia DUI Lawyer

Being charged under any of Virginia’s DUI laws is serious. The good news is that an arrest is not a conviction, but trying to fight these charges on your own will not put the odds in your favor. This is particularly the case if you also refused a breathalyzer test or have other complications such as multiple DUIs or an accident. Each case is unique, but having skilled legal counsel in your corner is a must. There may be issues related to the legality of the stop, the testing equipment, or the protocol used when asking you to submit to tests that could impact your case in your favor. If you’ve been charged with DUI, you need representation by an experienced and qualified Virginia DUI attorney.

At Pack Law Group, we have a thorough understanding of these cases and will act quickly to protect your rights. Don’t leave your freedom and future to chance. Contact our Lynchburg office now at 540-586-7225 or reach us online to schedule a consultation.