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Hinman Law Blog

FST / Breathalyzer


In Massachusetts, you can be arrested for drunk driving on a theory of impairment, where Field Sobriety Tests (FSTs) or other factors indicate that you are impaired as a result of alcohol consumption. You can be arrested on this theory even if you do not submit to a Breathalyzer test, or even if your Breathalyzer results are below .08%. Field Sobriety Tests are a series of three tests that have been recommended and standardized by the National Highway Traffic Safety Administration (NHTSA). The series of tests consists of the Horizontal Gaze Nystagmus (HGN) Test, the “Walk and Turn” Test, and the “One Leg Stand” Test. Most people do not realize that is well within your rights to decline to take Field Sobriety Tests. If you do not take field sobriety tests, you may be arrested, but you will not lose your license as a result of your refusal, and your refusal cannot be used against you at trial.

Horizontal Gaze Nystagmus Test (HGN):

In this test, the arresting officer will use some sort of stimulus, such as a small light or pen, and move it side to side and ask that you follow the stimulus with your eyes. One of the things that the officer is looking for is called “lack of smooth pursuit.” Essentially, the eye will make a jerking motion as it moves from side to side, or look like it’s rolling over sandpaper rather than a smooth surface. This is a very scientific test, and therefore is inadmissible in court if the witness does not have proper training and expertise. Additionally, there are other factors such as medical conditions that can affect the outcome of this test.

Walk and Turn Test:

The Walk-and-Turn test is a “divided attention” test where you are required to listen and follow directions while performing the task. You will be asked to take a certain number of steps, heel to toe, in a straight line. The officer will not only be observing your ability to walk in a straight line, but will also be taking note of your ability to listen and follow directions.

One Leg Stand Test:

This is another “divided attention” test where you will be asked to stand on one leg and count for a specified amount of time. The officer will be observing whether or not you are able to balance without swaying or using your arms, and will also be watching your ability to listen and follow instructions.

Challenging Field Sobriety Tests

Often, there are many factors at play when you are pulled over — fear, confusion, and intimidation, to name a few. These can easily affect your performance on Field Sobriety Tests. Standing on one leg and walking in a straight line may seem like simple tasks on their own, but when you are the side of the highway with cars speeding by, it can be a very different story. Things like weather, physical shape, footwear, or medical conditions may also affect your performance. At our initial free consultation, we can discuss the circumstances of your arrest at length, and work with you to develop the strongest defense for your case.


If your Breathalyzer results show a Blood Alcohol Concentration (BAC) of .08% or higher, you will automatically be arrested for drunk driving. It is important that you have a criminal lawyer with knowledge of Breathalyzers and how they are best contested in court. In Massachusetts, a BAC of .08% or higher is considered “per se” evidence that you are intoxicated. Breathalyzer machines measure the amount of alcohol on your breath on the theory that the alcohol concentration in your breath correlates to the alcohol concentration in your blood. You may be given a portable breath test at the site of your arrest, but these are generally less accurate and not admissible in court. If you consent, you will be given a Breathalyzer Test at the police station. There is extensive case law and written procedures in Massachusetts that dictate very strict protocol that law enforcement agencies need to follow in terms of maintaining, calibrating, and administering Breathalyzer Tests. It is also your right to insist upon being released from the police station as soon as possible in order to obtain an independent blood test. Blood tests are often more accurate than breath tests.

Challenging a Breathalyzer Test

You may think that because you failed a Breathalyzer case, you have to plead guilty. This is not always the case. There are many ways that Breathalyzer results can be challenged in drunk driving cases. For example, improper maintenance, calibration, storage, or use of the machine, skill or experience of the arresting officer, as well as failure to follow written procedure or obtain proper consent are all issues that are often raised in court. Additionally, there are several factors that can result in inaccurate Breathalyzer readings: temperature, atmospheric pressure, blood or vomit in the mouth, certain medical conditions, or exposure to certain chemicals or fumes, for example.

It is in your best interest to have a criminal lawyer that is well versed on police procedure when it comes to Breathalyzers. As a former prosecutor, Attorney Hinman has been trained by the State Police, and has the knowledge necessary to successfully challenge your Breathalyzer results.

If you have been charged with OUI/Drunk Driving in Wellesley, Natick, Needham, Dedham, Newton, Boston, or any town in Middlesex, Norfolk, or Suffolk Counties, contact Attorney Hinman at 617-283-4480, or use the form to the left for an immediate response!