How Police “Prove” Intoxication

Operating while intoxicated (OWI) is a severe criminal offense, and unfortunately, prosecutors across the country create hundreds of thousands of OWI and driving while under the influence (DUI) charges every year. Many people wrongly assume that an OWI is a shut-and-closed case, but that’s not true. This reality becomes apparent when you examine how police “prove” intoxication.

Probable Cause

An officer cannot force someone to take field sobriety tests without probable cause. Unfortunately, the determination of probable cause in a DUI arrest is often subjective. For example, an officer can force someone to take a field sobriety test if he or she smells like alcohol. As we all know, someone’s sense of smell is subjective: what smells good to one person may smell bad to another, and what smells like alcohol to a cop may be something else entirely.

Other subjective probable cause examples include:

  • Slurred speech;
  • Red face;
  • Extremely erratic driving;
  • Bloodshot eyes;
  • Odd behavior;
  • Having your lights off at night.

Field Sobriety Tests

A police officer is only a person and is therefore undoubtedly wrong from time to time. Sadly, a police officer’s mistake can end up costing innocent people time, money, and freedom. This is especially true when reviewing OWI testing procedures.

HGN Test

Every standard field sobriety test is subjective in some way. During the horizontal gaze nystagmus (HGN) test, an officer is supposed to watch the accused’s eyes to see if there is an involuntary jerking of the eyeball. However, HGN is known to occur in all people’s regardless of their blood-alcohol content (BAC). Therefore, cops are supposed to determine subjectively if the accused’s HGN movements are “higher than normal.” This process isn’t an exact science.

Walk-&-Turn Test

During this test, the accused is directed to take nine steps, touching heel-to-toe, along a straight line. After taking the steps, the suspect must turn on one foot and return in the same manner in the opposite direction. During the test, the officer is looking for eight indicators of impairment.

Some of the “indicators of impairment” of the accused during the walk-and-turn test include:

  • Starting before instructions are given;
  • Failing to keep balance during instruction or the test;
  • Failing to touch heel-to-toe while walking on the line;
  • Making an improper turn.

A 1998 validation study found that 79% of individuals who exhibit two or more of the eight indicators will have a BAC of 0.08% or higher. However, this means that 21% of people “fail” this test by presenting two or more of the indicators while sober. This test is not a foolproof plan.

One-Leg Stand Test

The one-leg stand test is when the accused must stand with one foot approximately six inches off of the ground and count aloud by ones (one-thousand-one, one thousand-two) until he or she reaches 30 seconds.

The four “indicators of impairment” during the one-leg stand test include:

  • Swaying while balancing;
  • Using arms to balance;
  • Hopping to maintain balance;
  • Putting the foot down.

Similar to the walk-and-turn test, researchers conducted a validation study in 1998 to determine if the one-leg stand test was effective. The study found that 83% of individuals who exhibit two or more of these indicators will have a BAC above 0.10%. However, this means that 17% of people “fail” this test by presenting two or more of the indicators while sober. Therefore, one out of every six people will “fail” the test while sober.

Breathalyzer Test

A breathalyzer test is supposed to obtain the percentage of alcohol in someone’s blood. Anyone with a BAC of 0.08% or more can be arrested for an OWI. Surprisingly, a preliminary breath test made on the field cannot be used as evidence in court. The only breathalyzer tests that can be used as evidence are tests that were taken by a DataMaster DMT breath test at a police station.

While a preliminary breath test cannot be used to secure a conviction, it can be used to secure an arrest. This fact shows that the criminal justice system does not wholly believe in the readings of breathalyzers used in the field. This calls into question the legitimacy of DUI arrests when using breathalyzers in the field.

Common problems with breathalyzers include:

  • Wrong calibration;
  • Operator error;
  • Alcohol absorption post-driving.

Accused of an OWI?

When police “prove” a suspect’s intoxication, it’s often based on subjective circumstances that the attorneys of White Law can argue against in a court of law. You don’t have to accept the charges made against you, and you don’t have to plead guilty.  You can fight against operating while impaired charges, and there is hope for your case.

If you or a loved one has been accused of an OWI, you should get experienced representation for your case. With decades of trial results, you can trust White Law to defend your rights properly.

Call (517) 316-1195 now for a free consultation for your DUI case.