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Hutchinson, MN Lawyers and the DUI Field Sobriety Tests

by | Oct 7, 2019 | Criminal Defense, Drunk Driving, Firm News

In McLeod County, officers usually administer four FSTs (Field Sobriety Tests) during DUI arrests. These tests always play a critical role in the process.

Officers must have probable cause before they request a chemical breath or blood sample. In most cases, the FSTs provide this evidence. Probable cause is a rather low standard. However, if the defendant only performed one or two tests, it is not easy for prosecutors to establish probable cause in a pretrial hearing.

Furthermore, in about one in five cases, defendants refuse to provide chemical samples. In these situations, prosecutors normally rely on FST evidence to establish guilt beyond a reasonable doubt. That’s a much higher standard of proof.

So, Hutchinson, MN lawyers must undermine the FSTs if at all possible. Failure to do so may be the difference between a positive and negative final result.

Horizontal Gaze Nystagmus

Typically, the DUI eye test is the first FST. The HGN test is normally reliable, if it is conducted in controlled environments. Roadside HGN tests are not controlled environments. Additionally, the presence of HGN is not a very good indication of intoxication, or the lack thereof.

HGN, which is also called lazy eye, causes involuntary pupil movements at certain angles. Officers look for these movements when they ask suspects to track moving objects using only their eyes. Alcohol intoxication causes nystagmus, but it is not the only cause. In fact, it is not even the leading cause. Childhood brain injuries cause many more HGN cases than alcohol intoxication.

Many times, the symptoms are so mild that people do not even realize they have lazy eyes. The symptoms only appear during periods of extreme stress, and a DUI arrest certainly qualifies as such.

Walk and Turn

The WAT, which is also known as the heel-to-toe walk test, is a divided attention exam. It measures both mental acuity and physical dexterity. So, during the test, officers look for a number of clues in both areas, including:

  • Beginning the test before the officer says “start,”
  • Taking the incorrect number of steps,
  • Failing to walk on a straight line,
  • Using arms for balance,
  • Swaying while walking or standing still,
  • Failing to walk heel to toe, and
  • Ending the test before the officer says “stop.”

This test has a number of deficiencies. For starters, there is a big difference between walking an actual line, like a parking lot stripe, and walking an imaginary line. Moreover, if the defendant is wearing anything other than athletic shoes, it’s very hard to walk heel to toe.

Flicker vertigo may affect this test as well. This conditions may also affect other tests, especially the DUI eye test. This condition affects may pilots. The flickering lights on instrument panels have a disorienting effect. The same is true of flashing strobe lights atop police patrol cars.

In fact, squad car lights are designed to cause flicker vertigo. The flashing lights disorient suspects, making them easier to subdue. That’s also the reason officers yell different things at the same time. The cacophony of sounds also has a disorienting effect.

Hutchinson, MN Lawyers and the One Leg Stand

The OLS is quite similar to the WAT. Both tests are divided attention tests. So, officers look for both mental and physical intoxication clues.

Additionally, both tests are almost impossible to complete if the defendant has any mobility or other physical impairments. Hutchinson, MN lawyers can often use these impairments to question the test results. Moreover, prosecutors must establish that defendants failed the OLS because they were intoxicated, and not because they were tired, nervous, or clumsy.

In court and at the administrative license revocation hearing, officers invariably testify that the defendant “failed” the OLS. Many times, officers assign failing grades because of technicalities, like holding the elevated leg at slightly the wrong angle.

Portable/Preliminary Breathalyzer Test

Not many other states use PBT tests. These roadside Breathalyzer tests are not nearly as reliable as the larger models at police department stationhouses.

For example, if the defendant burped or belched in the fifteen minutes prior to the PBT, ethanol particles flood into the mouth. These extra particles affect the results. Generally, the arrest encounter does not last fifteen minutes. So, Hutchinson, MN lawyers can often create reasonable doubt on this point. Officers have not watched the defendant for fifteen minutes, so they do not know whether the PBT test is accurate. Flaws like this one are especially critical in .08, .09, and other borderline BAC cases.

The Fifth Amendment gives defendants an absolute right to refuse all FSTs, including the PBT. Police station Breathalyzer tests are different. If the defendant refuses, that refusal may be admissible in court, and the defendant may be charged with a separate criminal offense.

Connect with a Dedicated Attorney

Unreliable FSTs greatly impact DUI prosecutions. For a free consultation with an experienced Hutchinson, MN lawyer, contact Carlson & Jones, P.A. Convenient payment plans are available.