Challenging Breathalyzer Tests in Massachusetts

In Massachusetts court, a DUI defense attorney may challenge the reliability of breathalyzer tests. Calibration errors, improper maintenance, and certification issues could cause a false or inadmissible reading. Only certified operators can administer a breath test.


Just because you failed a breathalyzer test, doesn’t mean your case can’t be won at trial.

There are several ways a skilled and experienced DUI defense attorney can defend you. Challenging breathalyzer tests in Massachusetts is a matter of identifying any errors in testing protocol, challenging the validity of test results, or attacking the integrity of breathalyzer machines themselves.

Breath test evidence can be suppressed, which means it won’t even be mentioned at trial. If this evidence is removed from the equation, you’ll have a better chance of obtaining a Not Guilty verdict.

Here are some of the ways an experienced DUI attorney can challenge breathalyzer tests in Massachusetts.

New Call-to-action

  1. 1. Challenging the Traffic Stop

You can challenge the reason you were pulled over. If it is determined that you were stopped unlawfully, the breathalyzer test will be thrown out, as will any other evidence relating to your traffic stop.

An unlawful stop occurs when police don’t have reasonable suspicion that you may be violating the law. Police obtain reasonable suspicion for a variety of reasons.

They may pull you over if they see you driving erratically, if they observe you drinking or driving, or if there are issues with your vehicle that warrant a stop. They cannot pull you over simply because you left a bar, because you were driving at night, or because they have a “hunch.”

  • 2. Challenging the Breathalyzer Results

The police are required to observe you for 15 minutes before administering an evidential breathalyzer test.  The purpose of this observation period is to preserve the integrity of the breath test result.

Often, the police will say that  they observed you for 15 minutes, but other evidence will demonstrate that they did not. If the test was conducted improperly, the results of the breathalyzer test may be suppressed.

The government must produce documents that detail the certification and testing of the machine that was used. Breathalyzer evidence may be suppressed if:

  • The government fails to produce these documents in a timely fashion
  • The machine is found to be faulty
  • The government can’t produce a proper witness to testify that the machine was maintained properly

Additionally, your DUI defense attorney may call upon expert witnesses to aid in your defense. Such experts could testify that there is a problem with the machine or that the science behind the machine is faulty.

An independent medical expert could even testify on your behalf if you have a medical condition that could inflate test results. You have a right to an independent medical examination. If the police didn’t inform you of this right, breathalyzer test evidence may be suppressed.

  • 3. Addressing Margin of Error

A Massachusetts DUI attorney could argue that the breathalyzer’s margin of error means you could have been below the limit. This could make breath test evidence suspect in your case, as the prosecution may have difficulty proving beyond a reasonable doubt that you were over the legal limit at the time you were driving.

This is generally only a viable defense if your breathalyzer test showed that you were extremely close to the 0.08% limit or if the machine in question is shown to be faulty.

  • 4. Current Events Regarding Massachusetts Breathalyzers

In August and September of 2017, it was discovered that the state withheld evidence that breathalyzer machines in Massachusetts were faulty. This casts into doubt numerous current and past cases involving DUI defendants and breathalyzer evidence. District Attorney’s offices across the state have suspended the use of breath test evidence.

This isn’t the only case in which breathalyzer tests have been called into question. In recent years, these tests have been shown as faulty in multiple states, including Colorado, Arizona, and New Jersey. This is usually the result of improper certification, calibration, and documentation, or because of other mistakes made by the government.

Massachusetts Breathalyzer Defense

There are many other ways a skilled DUI attorney can defend you against breathalyzer evidence. If you’ve been charged or arrested for DUI in Massachusetts, contact a DUI attorney as soon as possible. An attorney will review your case, walk you through next steps, and represent you in court.

New Call-to-action

Call DUI Attorney Joseph J Higgins for a free case evaluation today at 508-930-4273