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DWI and DUI Field Sobriety Tests and Defenses

DWI CHALLENGES AND DEFENSES - Minnesota Drunk Driving, Minnesota DWI, Minnesota DUI

There are many challenges to Minnesota DWI/DUI arrests. The fact is that officers must follow very strict and detailed procedures. If they deviate from proper DWI/DUI standards at any point, the case can be dismissed. In this article we have outlined a small number of the procedures followed. For a review of your particular case, call us at 612.240.8005.


It is no surprise that most DWI arrests occur between the hours of 11 p.m. and 2:30 a.m. This is prime drinking time and in most states the time that bars are getting ready to close. As a result, law enforcement officers find a myriad of different reasons to stop drivers during this time period. One of the challenges to a DWI is that the stop itself was invalid and based on pretense rather than actual facts supporting a suspicion of illegal conduct.

For a stop to be valid, the officer must have a reasonable suspicion that a specific crime has been committed. It is insufficient, for example, for an officer to stop a vehicle simply because it looked generally suspicious. There must be some indicia that a specific crime has been committed. Often officer make an error in this area and the stop itself can be challenged. If the stop is invalid, anything stemming from the stop including field sobriety tests and later breath, blood or urine tests, may suppressed.

The officer will often cite a number of driving symptoms that they are trained to look for as indicia that a driver may be impaired. Far too often, these claimed symptoms are simply a fiction created to validate the stop. Driving symptoms include:

  • weaving (within the lane or crossing lane lines). This can sometimes be combated by taking photographs of the roadway which may show that snow covered lane line or that lane lines had eroded over time and failed to exist where the officer claims a lane lines was crossed. If an officer can be impeached on this point, his credibility is strained and may result in a dismissal.
  • wide or slow turns. Officers often claim that they stopped a driver because they made a turn that was too wide or that the turn was made too slow. This can often be impeached by reviewing the corner where the alleged conduct occurred. A turn that is wide may, in fact, violate no traffic laws.
  • speeding. Often law enforcement officers will contend that a driver was exceeding the speed limit. This is easily contestable if the officer did not use a laser or radar device to calculate the speed. It is not unusual for an officer coming from the opposite direction to surmise that a car traveling the opposite direction is exceeding the legal limit without using any reliable measurement techniques.
  • minor violations. If the officer is unable to observe any obvious inappropriate driving conduct they may offer as a reason for their stop minor violations such as seat belt violations, objects hanging from the rear view mirror or even having a license plate that is obscured or with a license plate light that is too dim. Sometimes these claimed reasons for a stop violate the law, far too often, they do not.


After a vehicle has been stopped, there has been a seizure. As a result, the officer can go no further if his/her suspicions regarding criminal activity that lead to the stop do not pan out. For example, if the reason for the stop was that the driver did not have a front plate displayed and it turns out the driver has a valid application for a plate displayed or perhaps is a dealer vehicle requiring only one plate displayed, the officer can proceed no further.

In most cases the officer will approach the vehicle and is trained to ask "Do you know why I stopped you." The officer is trying to elicit incriminating information from the driver as to why the driver was stopped. Stating any reason for the stop is a mistake. It re-enforces the basis for the stop.

At this point, if we are to believe police reports, the officer possesses blood hound senses and is able to smell a scent of alcohol coming from the the vehicle. This is a very interesting point for many reasons. First of all, any scent may emanate from the vehicle itself or a passenger and not the driver. Second, alcohol has no odor. The officer must testify that he/she smelled an alcoholic beverage and its additives. Not all alcoholic beverages smell the same and the officer undoubtedly will be unable to identify the specific beverage. Moreover, there are numerous non-alcoholic beverages with similar additives from near beer to virgin mixed drinks, to non-alcoholic wines.

The officer will follow up his or her observations often with the question "Have you had anything to drink?" All too often people answer with "a couple" or "two" apparently believing that such a response will avoid further inquiry. Nothing could be further from the truth. Such an answer validates the officer's claimed observations and will undoubtedly lead to field sobriety tests.


Field Sobriety Tests (FST's) are the tests that are given by an officer at the road side. The officer must have probable cause to believe a drunk driving violation has occurred in order to take the driver to the station for additional testing. What the officer will not tell you is that these tests can be refused.

Almost every knowledgeable DUI / DWI attorney will say to you, "NO. Don’t attempt ANY ‘field tests." That is because you are designed to fail all field sobriety tests based on their nature. It is a failure to ask for instructions more than once. It is a failure to start before the officer tell you to. It is a failure if you perform too well and go beyond what the officer asks you to do.

These evaluations are nothing if not subjective. The accuracy of the tests is based purely on the credibility of the officer requesting the tests.

The three major tests are

  • walk and turn

  • the one leg stand

  • horizontal gaze nystagmus (HGN test). It is often referred to by people stopped as the "eye test."

Most law enforcement officers administering these tests instruct the person incorrectly on how to perform them or administer them incorrectly. If done incorrectly, these evaluations have no predicted reliability.

"Horizontal Gaze Nystagmus"

The most common test is one that involves following a pen, light or finger with the eyes while keeping the head still. It incredibly unreliable. It requires that the officer not administer the test to a person with hard contacts. Additionally, other conditions may affect the condition of the eyes resulting in an invalid result.

Walk and turn

This test requires a driver to walk heel to toe and turn. It must be performed on a surface where a clean line is visible and where there is a level, non-slippery surface. Obviously such a surface is difficult if not impossible to find in Minnesota's winters.

One Leg Stand

This test is also affected by weather conditions, shoes worn, surface and lighting. It can be affected by physical disabilities and age.

Finger to Nose

This is an older test which is not regularly given. Scientific tests have determined that it is all but useless to determine the effects of alcohol. It can be impeached by good attorneys with a good grasp of the test and the techniques it employs.

Alphabet Reciting

There is no scientific basis for this test. It is affected by education, learning disabilities and much more.

All of these field sobriety tests are also performed in a foreign atmosphere with squad lights flashing, car lights and cars zooming by.

Breath Test

A breath test is often given at the scene. This is called a preliminary breath test (PBT). This test cannot be used in Court. There is a very simple reason that it cannot be used in Court, it is inaccurate and prone to incorrect results caused by many factors, not the least of which is weather.


Once a driver is taken to the police station, the officer must observe that individual continuously for at least fifteen minutes. This observation period is necessary to ensure that the driver does not vomit, belch or do anything else that could impair the breath test results by creating mouth alcohol which will not provide an accurate reading of alcohol. This also can be affected by medical conditions such as acid reflux.

In most cases, the officer pays little attention to the driver as he/she fills out paperwork.

The officer does not have to read a Miranda warning. Instead, the officer must read (and where possible, tape record) an abbreviated version of rights called an Implied Consent Advisor. That advisory informs the driver that they have a right to call and consult with a lawyer and that a refusal to take a test is a crime. If the individual wishes to contact a lawyer. A telephone and a way to contact the lawyer (phone books) must be provided. The officer cannot direct the driver on what group or individual attorney they should call. To do so will deprive them of their right to counsel.

You do not get to choose the test that is given. Many times drivers believe they can request a different test than the one that is offered. That is not the case. Although an inability to perform the test offered can certainly impair the results. A person with asthma or suffering from pneumonia may be unable to provide a breath test or even a blood test because, as a result of dehydration, veins roll when blood is attempted to be drawn.

For legal representation call 612-240-8005 or ASK-A-LAWYER Online

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Any information contained on this site is general in nature. You should not rely on any articles, postings or other information on these pages as legal advice or to create an attorney-client relationship. If you are in need of legal advice concerning a particular matter, you are encouraged to contact an attorney in your state.

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