The Shortcomings of Breathalyzer Tests

August 08, 2014

breath-analyzer2A breathalyzer, short for breath analyzer, is the first test you will have to go through when a police officer asks you to pull over for suspected driving under the influence (DUI). You are most likely to experience this when the police see you are doing any of the following:

  • Erratic driving
  • Driving on the road’s center lines
  • Making extremely wide or narrow turns
  • Driving very slowly
  • Driving too close to another vehicle
  • Driving recklessly

Breathalyzers are used to determine breath alcohol content (BAC) by blowing onto it. Through a standardized formula, it will then produce the blood alcohol content, indicating the person’s level of impairment.

This article aims to inform the readers about breathalyzer facts they need to know — the kinds of breathalyzers, their accuracy, and find out if you can refuse to take the test. This is especially useful to the residents of Denver, Colorado where DUI laws have heavier penalties than other states.

Two kinds of breathalyzers

There are three chemical tests the police can use to determine your BAC:

  • Breath/breathalyzer test
  • Blood test
  • Urine test

Among them, the most commonly used is the breathalyzer test and it has two kinds:

  1. Portable or preliminary breath test (PBT) – It is the one a policeman brings with him on the road and uses it before making a DUI arrest. Being described as portable, it is the smaller of the two kinds. One thing many people don’t know is that it is not admissible in court. However, it can be used to determine probable cause for DUI.
  2. Evidentiary breath test – Although some police mobile units are equipped with it, it is most often done at the police station. The state of Colorado uses a machine called Intoxilyzer 5000 for the evidentiary breath test and its results are used as evidence in court. Refusing to take this test is a violation of the Implied Consent law.

PBT produces inaccurate results

Getting arrested for DUI because you failed the PBT does not mean it’s already the end. For one, breathalyzers are not always correct. Another, there are other factors affecting the PBT’s results.

Breath testing devices should be carefully maintained and calibrated in order to produce accurate results. PBT, being the one carried by the police everywhere they go, should be thoroughly taken care of. Mishandling of the device can lead to misleading results and wrongful arrests.

You mouth can also acquire alcohol from certain conditions, situations and substances other than alcoholic beverages which may affect the PBT result. These are the following:

  • Mouthwash
  • Dentures
  • Acid reflux
  • Vomiting 15 minutes before the test
  • Blowing on the device for too long

If you are truly innocent or you believe there is not enough alcohol in your system to be arrested, your lawyer can look into these factors to question the accuracy of the test. He or she can also look at the way the test was administered by the policeman who arrested you.

Drivers must be informed that the blood test, not the breath test, measures the driver’s BAC accurately. More importantly, uncontested studies by several researchers also proved that the margin of error when comparing PBT results to blood test results is an astounding 50 percent.

To put that in perspective:

  • A PBT result of .1 percent means an actual BAC of .05 to .15 percent
  • PBT reading must be over .2 percent for an arrest to be made
  • PBT result in between .1 and .2 percent means the DUI is in rebuttable presumption of guilt

With the public’s acceptance of the thought that PBT’s measure BAC without knowing its inaccuracy, many can be wrongfully arrested or charged with DUI. That is why it is important that you know these things and know when to seek the help of a DUI lawyer to defend you.

Can you refuse the breathalyzer test?

The Colorado Law on PBTs 42-4-1301 CRS says:

“(I) Following the lawful contact with a person who has been driving a motor vehicle or vehicle and when a law enforcement reasonably suspects that a person was driving a motor vehicle or vehicle while under the influence of or while impaired by alcohol, the law enforcement officer may conduct a preliminary screening test using a device approved by the executive director of the Department of Public Health and Environment after first advising the driver that the driver may either refuse or agree to provide a sample of the driver’s breath for such a preliminary test; except that, if the driver is under twenty-one years of age, the law enforcement officer may, after providing such advisement to the person, conduct such preliminary screening test if the officer reasonably suspects that the person has consumed any alcohol.”

All the roadside tests or field sobriety tests, including PBT, is voluntary and not required by the law. As mentioned above, the police officer must tell you first that you can agree or refuse to do the tests. However, if you have already injured someone else or yourself by your suspected drunk driving, you have no choice but to take the PBT. Otherwise, you will be taken to jail and your license will be suspended.

DUI lawyers suggest not to take any of these tests and just remain silent. Anything you say can be used against you so not saying anything, except for your name is the best thing to do. Wait until you are brought to the police station for the evidentiary breath test. The police will be using a large equipment for the test. This test is mandatory so refusing to do it will get you penalized.


You have the right to refuse to take the PBT as it is proven to be inaccurate and unreliable. It does not measure correctly the level of impairment of the person suspected of DUI, making everyone vulnerable to wrongful conviction for DUI. Its inaccuracy can also make some people escape their punishment if they are really guilty of DUI.

More importantly, drivers should be informed about their rights and when they need the help of an attorney. In Denver, Colorado, where the government does not tolerate such acts and heavily penalize the offenders of DUI law, everyone must know the specifics of the law and the choice they should make when they get in trouble.

Lastly, elimination of the PBT device should be taken into consideration as it can greatly affect the life of every motorist in the country.