Breathalyzer Information

Breath Alcohol Tests

Breath tests are not as accurate as blood test. Each machine has its own limitations and problems.

Portable Breath Test (PBT)

There are two types of breath tests police will use in New Hampshire. The first is a roadside portable breath test (PBT). This test measures the alcohol on your breath / mouth alcohol. This test is often grossly inaccurate at it does not detect lung alcohol. This test is always optional, and there is no administrative license penalty for refusing to provide a portable / roadside. It may make sense for you to refuse to give a sample, although the police officer will likely use this decision to decide whether to arrest you.

See my video demonstrating how inaccurate a PBT can be:

Intoxilyzer 5000 EN (Breathalyzer)

The second, more accurate breath alcohol test is the full test at the police station. The present model breath machine being used by New Hampshire is the Intoxilyzer 5000.

N.H. DWI GUY owns a working Intoxilyzer 5000. I can go over the machine with you in my office. Before giving you the test, the arresting officer will likely read you a form going over some of your rights in regard to the test. This test is also optional, but if you refuse it, you will lose your license for 6 months or 2 years, in addition to any license loss that may result if you are convicted of the criminal DUI charge. intoxsmall

However, if you give a sample that comes back .16 or higher, you will be charged with Aggravated DWI and face mandatory jail time. It may make sense to ask to speak to a lawyer first, if the police will allow it.

The person who administers the test must be certified, and the machine itself must be certified. A good DWI lawyer will be able to see if the person gave the test correctly, and if the machine operated correctly. You also have the right to get the breath sample you have been provided with independently tested. Attorney Hynes has experience to help.

Top 10 Problems with the Breathalyzer

1. It does not actually measure ethanol (drinking alcohol). The machine works by detecting very small amounts of particles that it considers alcohol, using light, based upon their wave - lengths. The problem is the machine is not specific to ethanol /drinking alcohol. It can detect other chemicals on the same wave-length, such as wood alcohol, isopropanol, acetone, and other chemicals.

2. The machine is not 100% accurate and has a margin of error. This is why the DMV will not act on a suspension for a BAC of .08.

3. The machine can be faulty and often breaks, which is why it is important to look at the machine log.

4. The operator may not have been certified.

5. The machine uses what is called a "partition ratio" to determining your BAC (Blood alcohol content) based upon BrAC (Breath alcohol content). The assumption it uses is 2100:1. Put simply, the machine assumes that a certain amount of breath alcohol translates to a certain amount of blood alcohol. The machine does this based upon AVERAGES in humans. However, not everyone has a partition ratio of 2100:1. If your partition ratio is different, which it likely is, your reading will either be too high or too low. Attorney Hynes is able to retain an expert chemist to better explain this to officers, judges, and juries.

6. The machine determines BAC using an assumption of your body temperature. Again, this is an average. If your body temperature was higher at the time, you will give a falsely high reading. This is particularly common for women who are in their pre-mesntrual phase, as their body temperature is usually higher during that time. Odds are pretty good the officer did not give you a thermometer to test your temperature. (I have never heard of an officer doing that, or asking a woman what phase of her cycle she is in).

7. Breathing patterns affect the machine. If you hold your breath, or blow for too long, or hyperventolate, you can be giving false results.

8. Radio frequency interferent RFI (radios, cell phones, etc.) interferes with the machine.

9. The machine will sometimes detect "mouth alcohol", which is different than alcohol from the alveolar air from the lungs lungs, or its blood equivalent. This is why the cop must watch you for 20 minutes prior to the test to see that you don't burp, regurgitate, or put anything in your mouth. Similarly, GERD - Gastroesophageal reflux disease - can give too high of a reading as air from the stomach (reflux) comes into the mouth.

10. Testing during the absorptive phase. The State must prove what your BAC was AT THE TIME OF DRIVING. Often, the breath test is around an hour or so after you were driving. During this time, the alcohol in your blood either increased, decreased, or remained the same. If you drank close in time before driving, the alcohol likely did not absorb into your body/blood at the time you were driving. Accordingly, by the time you gave the test and it did absorb, your reading would be faslely high.

How Many Drinks Does it Take to Get to .08?


N.H. DWI GUY owns and can operate an Intoxilyzer 5000 EN. He knows its limitations and its rate of accuracy. Some of you wonder how many drinks it takes to get to a certain BAC. While everyone is different, I made a video to give people an idea of what they might expect. For the test, I drank 4 shots of vodka in quick succession, and I weigh 180 pounds. After waiting the required time-frame, I ultimately peaked at .07.